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THE CHEMISTRY 

AXD 

TECHNOLOGY OF PAINTS 

By MAXIMILIAN TOCH 



11727/ S3 PHOTOMICROGRAPHIC PLATES 
AND OTHER ILLUSTK-ITIO.VS 




SECOND REVISED EDITION 



NEW YORK 

D. VAN NOSTRAND COMPANY 

1916 



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782555 



1 ■ ' ■ i 



• .. 1 ■; L j 



COPYRIGHT, 1907, BY 
D. VAN NOSTRAND COMPANY 

COPYRIGHT, 191 6, BY 
D. VAN NOSTRAND COMPANY 



• • • 

• • •• 

• • • • 
• •• • 



• •• 



•.• 



m 



• •••' 



- . • •••• ••'• 

• ••• :. ••:;••• 






••• - 

• • • 




THE-PLIMPTOS'PRKSS 
N O R W O o D • M A S S • I- • S • A 



PREFACE TO FIRST EDITION 

The difficulty which I encountered in writing this 
book was not how much to write but how much to omit, 
for I found on compiling my notes that I could very 
easily have made two volumes, each larger than the 
present one, and still would not have covered the ground 
thoroughly. It is for this reason that I have omitted 
many of the pigments which are rarely used, and have 
paid no attention whatever to the pigments which have 
gone out of use. 

I have not considered it desirable to use any space in 
this book with extended repetition o^ matter that can be 
found in other books of reference, for I have so much 
matter which is the result of original research that very 
few references are cited. 

This being the first book ever written on the subject 
of mixed paints, I am cognizant of the fact that there 
are many matters in it which I shall have to alter in 
future editions, and many subjects upon which I shall 
have to enlarge. It must be borne in mind that mixed 
paint is demanded by a progressive civilization and that 
there are no two manufacturers who make identically the 
same mixtures. As time changes, the progressive manu- 
facturer alters his formulas, and an indication of this is 
that the original mixed paints were mostly emulsions 
and soap solutions, whereas today the tendency is toward 
purity and improvement, and one manufacturer tries to 
outdo the other in making a paint that will last, the 
ideal paint, however, being never reached. 

3 



(. 



4 PREFACE TO FIRST EDITION 

This volume is intended for the student in chemistry 
who desires to familiarize himself with paint, or the 
engineer who desires a better knowledge of the subject, 
or for the paint manufacturer and paint chemist as a 
work of reference. It is not intended for those who have 
no previous knowledge or training in the subject. 

Some of the chapters in this book are taken from my 
lectures delivered at various universities, and others are 
extracts from lectures delivered before scientific bodies. 
One of the objects which I have had in view during the 
entire time I have been writing this book is to familiarize 
the student in chemistry, or the post-graduate, with the 
science and technology of modem paints, so that in a 
very short time the chemist unfamiliar with the subject 
may obtain sufficient knowledge to make a reasonable 
examination of paint. 

The chapter on linseed oil illustrates this, and my 
researches and theories on the difference between raw 
and boiled linseed oil are here' pubHshed for the first time. 
From the formulas and disquisition on the subject it 
can be easily seen that if raw linseed oil be taken as a 
standard nearly all comparisons fail if boiled linseed oil 
is under examination. 



320 Fifth Avenue 
New York, 1907 



PREFACE TO SECOND EDITION 

Since the first edition of this book was published the 
efforts of a large number of technical men working in this 
field have resulted in very important advances both in the 
production of new pigments, oils and special paints and in 
the scientific elucidation of many obscure phenomena in 
paint technology. Improvements have also been made in 
the method of manufacture as well as in the quality of 
many of the older pigments. Advances have also been 
made in the discovery and utilization of a number of oils 
which have not heretofore found extended use in the paint 
trade. 

These important advances have necessitated rewriting 
most of the book and the addition of new matter to the ex- 
tent of doubling its size. Some of the important additions 
which may be worthy of mention are, standard specifica- 
tions for pigments and oils; new special paints and driers; 
the theory of corrosion of iron and steel and its prevention 
as well as the action of fungi on paints; the important sub- 
ject of the hygiene of workmen ; detailed methods of analy- 
sis of paints and paint materials as well as tables of 
constants of such materials. 

Undoubtedly the chemical manufacturer and the chemical 
student who intends to become proficient in paint chemistry 
will find it essential to read a great deal of the past as well 
as the current technical literature of the subject, but it is 
the hop)e of the author that this hook will give the student 
a comprehensive survey of the progress already made and 
furnish a foundation for further improvement. 

MAXIMILIAN TOCH 
320 Fifth Avenue 
New York 
July, 1916 e 



CONTENTS 

Preface to First Edition 3 

Preface to Second Edition 5 

Introduction 13 

CHAPTER I 
The Manufacture OF Mixed Paints 18 

CHAPTER n 

The White Pigments 26 

White Lead. — Sulphate of Lead. — Sublimed White Lead. — 
Standard Zinc Lead White. — Ozark White. — Zinc Oxid. — 
Zinox. — Lithopone. 

CHAPTER III 

The Oxids of Lead 53 

Litharge. — Red Lead. — Blue Lead. 

CHAPTER IV 

The Red Pigments 62 

Venetian Reds. — Indian Red. — Permanent Vermilion. — Helio 
Fast Red. — Lithol Red. 

CHAPTER V 

The Brown Pigments 71 

American Burnt Sienna. — Italian Burnt Sienna. — Burnt Umber. 

— Burnt Ochre. — Princess Metallic or Princess Mineral Brown. 

— Vandyke Brown. 



8 CONTENTS 

CHAPTER VI 

The Yellow Pigments 78 

American Yellow Ochre. — French Yellow Ochre. — Chrome Yel- 
low. — Chromate of Zinc. 

CHAPTER Vn 
The Blue Pigments 84 

Ultramarine Blue. — Artificial Cobalt Blue. — Prussian Blue. 

CHAPTER VIII 
The Green Pigments 92 

Chrome Green* -^ Chromium Oxid. — Green Aniline Lakes. — 
Zinc Green. — Verte Antique (Copper Green). 

CHAPTER IX 
The Black Pigments 97 

Lampblack. — Carbon Black. — Graphite. — Charcoal. — Vine Black. 
— Coal. — Ivory Black. — Drop Black. — Black Toner. — 
Benzol Black. — Acetylene Black. — Mineral Black. 

CHAPTER X 

The Inert Fillers and Extenders no 

Barytes. — Artificial Barium Sulphate. — Barium Carbonate. — 
Silica. — Infusorial Earth. — Kieselguhr. — Fuller's Earth. — 
Clay. — Asbestine. — Asbestos. — Calcium Carbonate. — White 
Mineral Primer. — Marble Dust. — Spanish White. — Artificial 
Calcium Carbonate. — G)rpsum. 

CHAPTER XI 
Mixed Paints 140 

Anti-fouling and Ship's Bottom Paints. — Concrete or Portland 
Cement Paints. -^ Paint Containing Portland Cement. — Damp- 
Resisting Paints. — Enamel Paints. — Flat Wall Paints. — Floor 
Paints. — Shingle Stain and Shingle Paint. 

CHAPTER XII 
Linseed Oil 158 

Linseed Oil. — Standard Specifications, American Society for Testing 
Materials for Linsc»ed Oil. — U. S. Navy Department Specifica- 
tions for Linseed Oil. — Stand Oil. — Japanner's Prussian Brown 

on. 



r 

CONTENTS 9 

CHAPTER XIII 

Chinese Wood Oil i8o 

Chinese Wood Oil — A Method for the Detection of Adulteration 
of China Wood Oils. — Standard Specifications American Society 
for Testing Materials for Purity of Raw Chinese Wood Oil. 

CH.\PTER XIV 
Soya Bean Oil 192 

CHAPTER XV 
Fish Oil 203 

CHAPTER XVI 

Miscellaneous Oils 210 

Herring Oil. — Corn Oil. 

CHAPTER XVII 

Turpentine 217 

Turpentine. — Wood Turpentine. — Standard Specifications Ameri- 
can Society for Testing Materials for Turpentine. — U. S. Navy 
Department Specifications for Turpentine. 

CIL\PTER XVIII 
Pine Oil 228 

CHAPTER XIX 
Benzine 238 

CHAPTER XX 

Turpentine Substitutes 243 

Benzol. — Toluol. — Xylol. — Solvent Naphtha. 

CIL\PTER XXI 
Cobalt Driers 247 



lO CONTENTS 

CHAPTER XXII 

Combining Mediums and Water 254 

Combining Mediums. — Water in the Composition of Mixed Paints. 

CHAPTER XXIII 
Fine Grinding 259 

CHAPTER XXIV 
The Influence of Sunught on Paints and Varnishes .... 261 

CHAPTER XXV 
Paint Vehicles as Protective Agents Against Corrosion . . . 266 

CHAPTER XXVI 
The Electrolytic Corrosion of Structural Steel 276 

CHAPTER XXVII 
Painters' Hygiene 281 

CHAPTER XXVIII 
The Growth of Fungi on Paint. 284 

Analysis of Paint Materials 288 

White Lead. — Basic Lead Sulphate. — Zinc Lead. — Zinc Oxid. — 
Lilhopone. — Red Lead and Orange Mineral. — Iron Oxids. — 
Umbers and Siennas. — Mercury Vermilion. — Chrome Yellows 
and Oranges. — Chrome Greens. — Prussian Blue. — Ultra- 
marine. — Black Pigments. — Graphite. — Blanc Fixe. — 
Whiting. — GjTDsum or Calcium Sulphate. — Silica. — Asbes- 
tine. — Clay. — Barytes. — Barium Carbonate. — Mixed 
White Paints. — White Pigments. — Paints. — Rosin. — 
Rosin Oils. — Oils. — Etc., Etc. 



CONTENTS II 



APPENDIX 

Some Characteristics and Variables of Commercial Boiled 

Oils 343 

Characteristics of Boh-ed Oils (Lewkowitsch) 343 

CON\-ERSION OF FRENCH (MeTRIC) INTO ENGLISH MEASURE. . . 344 

C0NVT.RS10N OF French (Metric) into English Weight . . . 344 

Metric System of Weights and Measures 345 

Specific GRAvirv of Various Materials 346 

Specific Gravity of the Elements 350 

Pounds of Oil Required for Grinding 100 Pounds Various 

Dry Pigments into Average Pastes 350 

Specific Gravity of Various Woods 351 

Table Showing the Comparison of the Readings of Ther- 
mometers 352 

International Atomic Weights 353 

List of Photomicrographs 355 

Index 357 



THE CHEMISTRY 

AND 

TECHNOLOGY OF PAINTS 

INTRODUCTION 

The manufacture of mixed paints is essentially 
American, ha\dng been accredited to some enterprising 
New Englanders who observed that when a linseed oil 
paint was mixed with a solution of silicate of soda (water 
glass) an emulsion was formed, and the paint so made 
showed very little tendency to settle or harden in the 
package. Several lay claim to this discovery. The 
first mixed paint was marketed in small packages for 
home consumption and appeared about 1865. 

The addition of silicate of soda is still practised by a 
few manufacturers, but the tendency is to eliminate it 
as far as possible and to minimize as much as possible 
the use of an alkaline watery solution to keep the paint 
in suspension. The general use of zinc oxid has had 
much to do with the progress of mixed paint, for it is 
well known that corroded white lead and linseed oil 
settle quickly in the package, while zinc oxid keeps the 
heavier lead longer in suspension. Where only hea\y 
materials are used, manufacturers are inclined to add 
up to 4 per cent of water. Under another chapter on 
"Water in the Composition of Mixed Paints,'' page 254, 
this subject will be fully discussed. 

To the pigments are added many materials possessing 
but little body, hiding or covering property, which are 

13 



14 INTRODUCTION { 

known as inert fillers, and some of these, partictdarly 






the silicates of alumina and the silicates of magfcesia, 
the various calcium carbonates, and silica itself, are ^ used 
to counterbalance the heavy weight or the specific gravity 
of the metallic pigments; and whereas these inert fillers 
were formerly regarded as adulterants and cheapening 
agents, they are now looked upon as necessities, and the 
consensus of opinion among practical and many scientific 
investigators is that a compound paint composed of lead, 
zinc, and a tinting pigment, to which an inert material 
has been added, is far more durable than paint made of 
an undiluted pigment. The consuming public and the 
painter himself have not been sufficiently educated as yet 
to understand the merits of these diluents, and the paint 
manufacturer has been reticent in his statements regard- 
ing the use of various fillers. 

These facts account to a large degree for the opposi- 
tion to the use of such materials. When it is taken 
into consideration that within forty years the sale of 
mixed paints in the United States has grown to almost 
sixty million gallons per year (and the outlook is for a 
larger increase in the use of mixed paints), it is obvious 
that the demand is healthy, even though the manufacture 
of mixed paints has been directed or based largely upon 
empirical formulas. 

One of the railroads of the United States buys at this 
writing upward of one million dollars' worth of paint 
material per year, a large share of this being mixed paints, 
or paint ready for the brush. Nearly all of the large 
manufacturing industries which use large quantities of 
paint are gradually altering their methods, so that their 
paint comes to them ready for application. In no case, 
to the best knowledge of the author, does a single one 
of these industries prescribe a single pigment with linseed 



y 



INTRODUCTION 15 

oil for general purposes, for it has been shown that a 
mixture of several pigments and a filler is superior from 
the standpoint of lasting quality and ease of application 
to a mixture of a single strong pigment and the vehicle. 

The structural iron industry, which has reached an 
enormous development in the United States, uses paints 
ready mixed with the one exception of red Jead, which, in 
the old prescription of thirty-three pounds of red lead to 
one gallon of oil, cannot be prepared ready for the brush, 
for reasons which will appear in the proper chapter. 

The manufacture of agricultural implements, wagons, 
and wire screens can be cited as industries in which manu- 
facturers have within a ver>' few years adopted the use 
of ready-mixed paints for their products. These paints 
are not brushed on, but are so scientifically made, and 
the relation between a vehicle and a pigment is so 
carefully observed, that large pieces of their products can 
be dipped into troughs and the paint allowed to drain. 
The surface is more evenly coated and the work done in 
far less time than would be required were it applied 
by means of the brush, as in former years. 

In \dew of all these facts, the prejudice on the part 
of the general pubUc and the trepidation of the manu- 
facturer are to blame for the unheralded knowledge of 
the constituents of mixed paints. There are many cases 
where materials which were once despised are regarded 
now as essential to the life and working quality of paint, 
and the attitude of the paint manufacturer must in 
the future be a frank and open admission of the com- 
position of his materials. If a paint is composed of a 
mixture of white lead, zinc oxid, and bar>'tes, and it has 
been proved that a mixture of these three will outlast 
a mixture of either of the other two, there is no reason 
why a manufacturer of mixed paints shall not so state. 



Vv 



l6 INTRODUCTION 

New materials have come into use which have taken 
the place in a large degree for many purposes of the 
time-honored and- useful white lead, and many mixed 
paint manufacturers have already begun to educate the 
public to the superiority of one material over another. 
It stands to reason, however, that the manufacturer of 
a raw material which has been in use for a very long 
time is going to refute as much as possible the statement 
made with regard to newer materials, and these dis- 
cussions tend to do good rather than harm. 

In the case of one of the large railroads, the speci- 
fications for a certain paint demand the use of over 70 
per cent of inert filler, and if these inert fillers had no 
merit no railroad or large corporation would permit their 
use. These large corporations support chemical labora- 
tories and employ the best talent which they can engage. 
They continually experiment, and in their specifications 
the results of their experiments are obvious, and there- 
fore if a large corporation can state publicly not only 
what the composition of these paints shall be, but con- 
clude that such compositions are based upon the results 
of scientific investigation, the paint manufacturer can 
do likewise and stand back of his products, provided they 
be mixtures of various materials which time, science, 
and investigation have proved to be superior. 

Unfortunately, however, there are some manufactur- 
ers who have "hidden behind a play of words" and per- 
mit chicanery and finesse to enter into the description 
of their products; but fortunately some of them have 
seen the errors of their way, and already there is a ten- 
dency toward openness and candor with regard to their 
wares. There was a time, and it still exists in a measure, 
when substitutes for white lead were very largely sold, 
and misleading labels appeared on the packages; for 



INTRODUCTION 17 

instance, a man would make a mixture of 80 per cent 
barytes and 20 per cent white lead, and would print 
on the label — "The lead in this package is guaranteed 
absolutely pure,'' followed by a commendation and 
guarantee that certain sums of money would be paid if 
the lead were not found to be pure. This, of course, is 
a moral fraud and an unfortunate play on the ambiguity 
of the language, and many of the manufacturers, in view 
of such unfortunate misstatements, are altering the 
names of their paste products, or lead substitutes, 
omitting the word "lead" entirely. 

Another unfortunate mistake is made when a manu- 
facturer makes a mixed paint and states on the label, 
"This paint is composed of pure lead, pure zinc, pure 
linseed oil, pure drier, and nothing else/' The analyses 
of the paint have proved that in addition to the "pure" 
products mentioned three gallons of water were added 
to every hundred gallons of paint in order to keep the 
paint in suspension, and that it had not been strained 
and therefore contained a large amount of dirt and for- 
eign matter. Ethics would clearly indicate that no 
manufacturer has a moral right to label his paint as 
being entirely pure and composed of four materials, 
when as a matter of fact an excessive quantity of water 
was added which destroyed in a large degree the value 
of the other materials. In another chapter the question 
of the percentage of water which may be contained in 
any paint will be thoroughly discussed. Three per cent 
is entirely excessive in an exterior linseed oil paint, and 
a manufacturer has no right, either morally or legally, 
to hide behind a misrepresentation of his paint when 
the paint is largely adulterated for the purpose of over- 
coming his ignorance in the manufacture. 



CHAPTER I 
The Manufacture of Mixed Paints 

The modem methods of making mixed paint are 
di\dded into two classes, which depend upon the specific 
gravity and fineness of the raw material. 

One of the methods employed is to mix the raw 
material with sufficient linseed oil to form a very heavy 
paste, the proper tinting material being added during 
the process of mixing. This paste is then led down 
from the floor on which it is made into a stone mill and 
ground. Even when the mill is water-cooled, the mass 
frequently revolves at such a speed that the paste paint 
becomes hot. It is then allowed to run from the mill 
into a trough called the "cooler," or is stored in barrels 
to be thinned at some later time. In case the operation 
is continuous and the paste is thinned at once, it passes 
from a stone mill to a mixer below which contains the 
requisite quantity of thinning material composed of oil, 
volatile thinner, and drier, where it is intimately mixed 
by means of paddles. It is then compared with the 
standard for shade, and if the tone should not be identical 
with the former mixing, either tinting material or pigment 
is added in sufficient amount to produce • the proper 
shade. From the last mixer, knowTi as the "liquid 
mixer," the paint is drawoi off and filled into packages, 
the final operation before allowing it to enter the package 
being to strain it. This method has been used ever 
since mixed paints have been made. The majority of 

i8 



THE MANUFACTURE OF MIXED PAINTS 19 

white paints, or paints of heavy specific gravity, are 
made in this manner. 

The paints of lower specific gravity, varnish and 
floor paints, are made differently. This method is really 
the reverse of the old-fashioned method, in that the 
liquid and pigment are placed in a mixer on an upper 
floor in the amounts necessarj^ to produce the correct 
consistency. The paint is run down in a thin stream to 
the floor below into a mill knowoi as the *^ liquid mill." 
The liquid mills revolve very rapidly, the stones being 
flat. 

According to the best practice of making paste 
paints a grinding surface is supposed to be conical, 
although there is much difference of opinion on this 
subject. When the paint has run through the stones of 
a liquid mill, it comes out of a spout and is then ready 
for packing, due precaution being taken, however, to 
strain it twice, once as it passes down into the liquid 
mill and again as it flows out. There is much difference 
of opinion among paint-making mechanics as to the 
proper surface which a grinding surface shall present; 
for instance, the first depression in the stone of a mill 
is deep, tapering toward the edge, and is known as the 
''lead.'' From the end of this *^lead'' fine lines radiate 
toward the "periphery'' of the stone. These are called 
the "drifts," and the paints containing silica wear off 
the surface of even the hardest flintstone mills, so that 
in well-regulated factories a man is always employed 
sharpening the mills, and by the term "sharpening" is 
understood cutting out the "drifts" and "leads." 

Not so many years ago paint mills were composed 
of either iron or steel, but in modem paint practice mills 
of this character have been abandoned, except for use 
as filling machines. They grind fairly fine when sharp. 



1. 



20 CHEMISTRY AND TECnNOLOGY OF PAINTS 

but inasmuch as all silicious paint materials are harder 
than steel or iron they become dull in a very short time. 
Then again, the attrition grinds off small particles of 
iron, which affect all delicate tints more or less. 

The arrangement of the tanks and mills in the factory 
is of the greatest importance. Taking up first the 
second method of mixing paint already described, the 
liquid and white base are mixed in large, heavy cast- 
iron mixers, which are located on a platform high 
enough to discharge into a liquid mill. (See Fig. i, 
Heavy Mixers.) 

The mixed material is ground through this mill and 
discharged from it into storage tanks situated con- 
veniently on a platform below the floor on which the 
mill is located, these storage tanks holding from 1500 
to 2000 gallons of the ground product. From the stor- 
age tanks a pipe-line with its various branches carries 
the paint to tinting tanks placed at convenient dis- 
tances from the storage tanks, the latter being high 
enough to allow the paint, by gravity, to flow through 
pipes to the tinting mixers. This pipe-line is made of 
wrought iron, the usual diameter of which is 4 inches, 
the joints being all flanged so that the pipes may be 
easily taken apart and cleaned. 

Underneath the storage tanks and close to the outlet 
is a master valve, so that the product in the tank may be 
shut off at any time and the flow cut out from the sys- 
tem of pipes. Opposite each tinting tank (these tanks 
should be in parallel rows and numbered to correspond 
to the tints that are to be made) a 2-in. branch pipe is 
connected to the 4-in. main, and each of these branches 
is furnished with a valve to control the discharge into 
the tinting mixers. The cast-iron mixers already men- 
tioned should be so arranged that two mixers work in 



THE MAXUFACTIRE OF MIXF.D PAIXTS 21 

conjunction with one mill. The mill is of stone and 
known as a liquid or incased mill, the usual diameter 
being 30 to 36 inches. 




I'm. 1 — Heavy !Mixi:ks 



The storage tanks are made of sheet metal with 
hea\'y sheet-steel bottoms, and are furnished with a 
slowly revolving stirrer to keep the ground liquid agi- 
tated. The outlet of these tanks is of generous size and 
covered with a steel wire screen to prevent any foreign 





fnr 



\:' ] 



-M 




■^^-^ 



THE MANUFACTURE OF MIXED PAINTS 23 

matter such as chips of wood or like material from getting 
into the supply pipes. Fastened to the stirrer of these 
tanks is a wire brush which scrapes the surface of the 
screen in its rotation around the tank, thus keeping the 
holes of the screen free for the proper flow of the liquid. 
The tinting colors used in this process are usually ground 
through small stone mills of 15 in. or 20 in. diameter, 
and are stored in convenient portable receptacles. 

This method of liquid paint-making reduces the 
handling and labor cost to a minimum, the hardest work 
being done on the mixer platform where the dry pigment 
and the proper amount of liquid are first mixed. In a 
factory where the floors are not arranged so that the 
method already described can be carried through by 
gravity alone, it is possible and practicable to introduce 
a force pump, preferably of the rotary type, to make up 
for this deficiency. When this latter method is used, 
the cast-iron mixer and mill should remain in the same 
relative position as before, but the storage tank could be 
placed in any other part of a building and on the same 
floor as the liquid mill, but high enough to discharge 
by gravity into the tinting mixers. The ground pig- 
ment would then be discharged into a small tank 
situated at the foot of the mill, to which the rotary pump 
is attached. As this tank is filled with the ground 
product, the pump would force it through the proper 
pipe connection to the storage tank, the connection 
from the storage tanks to the tinting mixers being the 
same as in the first described process. 

The other method in use is to mix and grind the 
pigment in paste form, using the same style of mixer; 
but instead of a hquid mill a paste mill is used. Situated 
at the back of this paste mill, and close to the discharge 
scraper, is a steel tank of generous dimensions (usually 



CHEMISTRY AND TECHXOLOCY OF PAINTS 




THE MANUFACTURE OF MIXED PAINTS 25 

500 gallons), into which the ground pigment is dis- 
charged. This steel tank is provided with a stirrer for 
mixing the ground pigment with the oil and other thin- 
ners that are added to it, in order to reduce it to a 
liquid form. It is then carried to the tinting tanks by 
a pipe-line on the same general plan as that heretofore 
described. 

One of the advantages of this plan is that this outfit 
can be used in a dual capacity, i.e. it can be used for 
the mixing of liquid paints after the plan described and, 
by changing the scraper from the back to the front of 
the mill, the outfit can be changed into a paste-grinding 
plant. 



THE PIGMENTS 

CHAPTER II 
The White Pigments 

The white opaque pigments used in making mixed 
paints are white lead, zinc oxid, sublimed white lead, 
leaded zincs, lithopone, and other zinc and lead 
pigments. 

Among the white leads there are several varieties; 
the principal ones, however, are the old Dutch process 
lead and the quick process lead, both of which are 
hydrated carbonates of lead. 

There are many varieties of zinc oxid made in the 
United States, depending largely upon the raw material. 
The grade made principally from spelter, according to the 
French process, is known in America as "Florence Red" 
and "Green Seal Zinc." The seals on zinc indicate the 
whiteness of color, the green seal being the whiter. In 
Germany the colored seals extend to a greater range 
than in America, the green seal being the whitest, the 
red next, the blue next, the yellow next, and then the 
white. 

The New Jersey zinc oxids are made direct from the 
ore and are almost as pure as the zincs made from the 
metal, but they have a totally different tone, being much 
more of a cream color than the so-called French zincs. 

The Mineral Point zincs made in Wisconsin contain 
a varying percentage of sulphate of lead. The leaded 
zincs of Missouri are analogous in composition to those 



WHITE PIGMENTS 27 

of Mineral Point, but the percentage of sulphate of lead 
is much higher. 

The standard zinc lead white of Colorado contains 
50 per cent oxid of zinc and 50 per cent sulphate of 
lead. Sublimed white lead is made in Joplin, Missouri, 
from Galena mineral, and will average 95 per cent 
ox>'sulphate of lead and 5 per cent zinc oxid. This 
material has been largely superseded by a white known 
as Ozark White, which is described under that heading. 

Lithopone is a double precipitate of sulphide of zinc 
and sulphate of barium. 

These are the opaque white pigments used in the 
manufacture of mixed paints. It is not wthin the power 
of any man to say which one of these is the best, because 
under certain circumstances one material will outrank 
another, and long practice has demonstrated that no 
single white pigment material is as good as a mixture of 
various white pigments for mixed paint. The differences 
of opinion and conflicting reports that one hears con- 
cerning these raw materials are largely due to competi- 
tion among manufacturers. Whenever a new material 
is exploited a manufacturer of a tried and staple pig- 
ment naturally finds the defects in the new material 
and informs his salesmen to this effect. And so when a 
material finally succeeds and takes its place among the 
recognized list of pigments it has gone through all the 
hardships and \acissitudes possible. 

For two thousand years, more or less, there was no 
other white pigment than white lead. Within the life- 
time and memory of many a paint manufacturer in the 
United States all the pigments described in the beginning 
of this chapter have been bom and have prospered. 
The great competitor of white lead is zinc oxid, and the 
weakness of white lead is the strength of zinc oxid, and 



28 CHEMISTRY AND TECHNOLOGY OF PAINTS 

vice versa. White lead, for instance, is a soft drier and 
zinc oxid is a hard drier. White lead finally becomes 
powdery; zinc oxid in its eventual drying becomes hard, 
and it is for these reasons that a mixture of zinc oxid 
and white lead forms such a good combination. On the 
other hand, it is regarded as a fact that a paint com- 
posed of an opaque white pigment in a pure or undiluted 
state should not be used, for experience and chemistry 
have both shown that an inert extender added in mod- 
erate proportions to the solid white pigment increases 
its wearing power, and when the surface finally needs 
repainting it presents a better foundation for future 
work. Taking all of these facts into consideration, a 
paint manufacturer who combines experience with the 
teaching of chemistry is quite likely to produce a mate- 
rial, that will add both to his reputation and his income. 
He Certainly has a great advantage over the man who 
works entirely by rule of thumb. 

White Lead 

Formula, 2PbC03-Pb(OH)2; Specific Gravity, 6.323106.492 

White lead is the oldest of all white paints, and prior 
to the middle of the last century it was the only white 
pigment in use with the exception of a little zinc and bis- 
muth. Within half a century quite a number of -other 
white pigments have come into use, and only gradually 
have the defects of white lead become known. However, 
paint manufacturers in the United States are very large 
users of dry white lead, which, together with zinc, 
asbestine, and other inert materials, forms the bases or 
pigments of the mixed paints. There seems to be an 
antagonism against the use of white lead which apparently 
is unfounded, for, although white lead may have its 



WHITE PIGMENTS 29 

defects, there is no other white pigment which is loo 
per cent perfect, and therefore it is only fair to give that 
time-honored material its proper due. White lead as a 
priming coat on wood, particularly when it contains 
more oil than should normally be used, cannot be ex- 
celled. 

The history of this pigment, its method of manu- 
facture, and the general uses to which it has been applied 
are so well known, and are 
generally given even in 
elementary text-books on 
chemistry, that it is not 
the author's purpose to 
take up much space for 
this subject. Briefly stated, 
however, there are two 
processes for the manu- , 
facture of white lead. One 
is called the Dutch process, 
which takes about ninety 
days and is a slow cor- 
rosion of a buckle of lead 
in an earthenware pot in the presence of acetic acid. 
Carbonic acid froirt fermenting tan bark acts on the 
lead, converting the material into hydrated carbonate 
of lead. In the other, which is called the quick 
process, the acetic acid solution is directly acted upon 
by Qither carbonic acid gas or an alkaline carbonate 
salt. Th^ old Dutch process is stUI much more largely 
used than the quick process, the resulting product being 
much more desirable from the practical standpoint. 
There are a number of other processes under a variety 
of names, but none of them differ \'ery much from the 
so-called "quick process." 




o. I. CoHHODED WsiTE LEAD — Pho- 
tomicrograph X150, of known purity 

and composition. 



n 



^:-n : 



30 CHEMISTRY AND TECHNOLOGY OF PAINTS 

White lead is in great favor with the practical painter, 
not for its wearing quahty, but principally for the free- 
dom with which it is applied. Although white lead is 
generally spoken of as a carbonate of lead, it is com- 
posed of approximately 69 per cent carbonate of lead, 
PbCOj, and 31 per cent of lead hydroxid, Pb(OH),, 
It is this lead hydroxid which combines quite rapidly 
with oil and forms an imctuous substance sometimes 
known as "lead soap.'' 
^^^ White lead is variable in 

.£^^ composition, the amount 
of hydroxid ranging from 
15 to 30 per cent. In 
* -'-,'' ■ ■ ■■; '^*: t ■>>■ ' addition to this, during 
. *^ -'.*.■■ ■*^'-,*'';' '.A iu ^^^ process of manufac- 
"-.''- :V-:'L,>.'^^ ^' ture of the old process 
* ' ■•r'''.- :, y^i^^'-'.Vj^:^ lead, and after its final 
^fcv^^i, ^*'^\' :;: washing, it is mixed witl 

-.. - .'Sir'- ' linseed oil while stiU in 

'''''" ' the wet state. The oi] 

No. 2. Old Process White Lead — , . ™. • 

Ptotomi.ragraph X250. havmg a greater affinity 

for the white lead thar 
the water has, the latter is displaced. A small per- 
centage of moisture adds to the free working quality ol 
the paint made from white lead. (See "Water in the 
Composition of Mixed Paints," page 255.) 

White lead is regarded as a poisonous pigment, and 
so it is, but this property should not condemn it foi 
application to the walls of a house or for general paint 
puqjoses, because its toxic effect cannot be produced 
from a painted surface. Its poisonous quality is mani- 
fest to the workmen in the factories where white lead is 
made, and also to the painter who is careless in apply- 
ing it. The unbroken skin does not absorb lead very 



WHITE PIGMENTS 31 

rapidly, but the workman inhaling lead dust, or the 
painter who allows a lead paint to accumulate under his 
finger nails, is likely to suffer from lead poisoning. In 
one or two factories where much white lead is ground, a 
small percentage of potassium iodide is placed in the 
drinking water. This overcomes any tendency toward 
lead poisoning, by reason of the fact that the soluble 
iodide of lead is formed in the system and the lead is 
thus flushed out through 

the kidneys. Charles Dick- -g*"**-! V^ ^ ji 

ens, in one of his short ^^' ■if'^^^rj' *\^* 
stories called "A Bright ^^%^ w-^A* *'■'* M-v 
Star m the East," com- ; '^■7i-v^y , t''^> ^|^ 

duced in a certain white »Jt'*^, i ^""i' .•' Ji^ ^ "f ""H 
lead factory in London, 
and expressed the hope 
that American ingenuity 
would overcome the dan- 
gers which beset the men. 
In one of the largest white •"• '■ ^.r^XXso"™' " 
lead works in New York 

City lead poisoning does not occur, owing to the in- 
genuity and care exercised by the management. 

The ratio of oil necessary to reduce white lead to the 
consistency of paint can by no means be given in exact 
figures. The old Dutch process lead will take four and a 
half gallons of linseed oil to one hundred pounds of white 
lead ground in oil, in order to obtain a paint of maxi- 
mum covering property. The new process lead will take 
more oil than this, and in many instances up to six 
gallons to the one hundred pounds of white lead paste, 
which contains approximately ly'ri- gallons of linseed 
oil. On a mixed paint basis, 60 pounds of dry white 




32 CHEMISTRY AND TECHNOLOGY OF PAINTS 

lead will take 40 pounds of linseed oil to produce the 
correct ratio, but in addition four pounds of volatile 
thinner, such as benzine or turpentine, can be added to 
increase the fluidity and assist in the obKteration of 
brush marks. No general rule can be given for the per- 
centage of oil necessary, as temperature has much to do 
wth this, but the difference in the amount of oil neces- 
sary to produce a good flowing paint during summer or 
winter can be approximately given as 10 per cent, less 
vehicle being necessary in summer than in winter. 

White lead when exposed to the elements becomes 
chalky after a while and assumes a perfectly flat appear- 
ance w^hich resembles whitewash, and comes off very 
readily on the hand. As long as there was no remedy 
for this there was no comment on the subject, but at the 
present time investigators have improved paint mixtures 
so that this defect is not so palpable as it was in former 
years. From many experiments made by the author 
the causes of the chalking of white lead may be sum- 
marized as follows: 

First. The action of the carbonic acid in rain water. 

Second. The action of sodium chloride (salt in the air). 

Third. The catalytic action of white lead itself in 
being a progressive oxidizer of linseed oil. 

First. If white lead be treated with water containing 
carbonic acid, it is found that the same solvent action 
takes place upon carbonate of lead as takes place upon 
calcium carbonate. 

Second. If white lead be treated wth a sodium or 
ammonium chloride solution, a solvent action is apparent, 
and its sodium chloride is always present in the air at the 
seashore, and carbonic acid is everywhere present in the 
atmosi)here and is readily taken up in a rain storm, the 
chalking of white lead can be attributed to these causes. 



WHITE PIGMENTS 33 

Third. This cause is, however, problematical and 
cannot at this writing be stated with any degree of 
positiveness. It is quite true that white lead and linseed 
oil do not attack each other so readily on an interior wall 
as they do on a wall exposed to the elements. 

One of the defects mentioned by many writers on 
white lead is its susceptibility to sulphur gases. In 
nature these sulphur gases are generated in two places; 
namely, in the kitchen of every house, and in and around 
stables and outhouses. In kitchens the cooking of 
vegetables liberates hydrogen sulphide to a great extent, 
the odor of which is familiar to everybody who comes into 
a house where either cauHflower or cabbage is being 
cooked. But, inasmuch as undiluted white lead is not 
often used for interior painting, the defect is not so 
noticeable. A few stables or outhouses are painted pure 
white, and when they are painted white the painter 
generally has sufficient knowledge of the subject to use 
zinc oxid instead of white lead. 

It cannot be denied that the ease of appKcation of 
white lead, as well as its enormous covering property, 
has had much to do with the preference for it as a paint. 
With the exception of lithopone, it has a greater hiding 
property, volumetrically considered, than any other white 
paint; on the other hand, gravimetrically considered, it 
has less body than any of the lighter paints. 

The addition of an inert filler, such as artificial barium 
sulphate, silica, and barytes, improves white lead con- 
siderably. These inert fillers, which will be considered 
under their proper chapters, are not affected by chemical 
influences in the slightest degree, and where they are 
used in the proper proportions additional wearing quality, 
or "life," as the painter calls it, is given to the paint. 
The percentage of inert fillers which can be added to 



34 CHEMISTRY AND TECHNOLOGY OF PAINTS 

white lead varies up to 50 per cent. More artiQcial 
barium sulphate than natural barium sulphate can be 
added. If a comparative exposure test be made, both 
on wood and metal, of undiluted white lead and white 
lead containing an inert extender, it will be found that 
at the end of eighteen months the paint which contained 
the filler is in a better state of preservation than that 
which did not contain it. Generally considered, white 
lead is an excellent paint, more particularly when added 
to other materials. 

Sulphate of Lead 

Formula, PbSOi; Specific Gravity, 6.2 to 6.38 

It must be borne in mind that the sulphate of lead 
of commerce, which is not so frequently met with nowa- 
days as formerly, is a very poor paint material, and it 
must not by any means be confounded with sublimed 
white lead, which is at times erroneously called lead 
sulphate. 

The lead sulphate of the paint trade is a nondescript 
article which was sold as a by-product by the textile 
printers who used acetate of lead as a mordant, and to 
this liquid sulphuric acid was added and the precipitate 
was sold to the paint trade under the name of lead 
bottoms or bottom salts. Occasionally this material is 
still met with, and wherever it is used in a mixed paint 
it does more harm than good. It is likely that the pure 
neutral lead sulphate, which is a good oxidizing agent, 
dries well, and covers fairly well, could be used for ordi- 
nary light tints if diluted with the proper inert materials, 
but the lead sulphate which is sold by the textile printers 
is always acid and is sometimes coarse and crystalline, 
though at other times quite fine. The chemist, the paint 



WHITE PIGMENTS 35 

maker, and the engineer must never confound this lead 
sulphate with the lead sulphate contained in sublimed 
lead, zinc lead, or leaded zincs. 

Sublimed White Lead 

Specific Gravity, 6.2 

Sublimed white lead is an amorphous white pigment 
possessing excellent covering and hiding power, and is 
very uniform and fine in grain. It is a direct furnace- 
product obtained by the sublimation of Galena, and 
within the last ten years it has come into great prom- 
inence among paint makers, now being regarded as a 
stable, uniform, and very valuable paint pigment. The 
author has examined a great many paints containing 
sublimed lead. Among one hundred reputable paint 
manufacturers in the United States sixty-five used sub- 
limed lead. About eight thousand tons were used in 
the United States in 1905. Considering the fact that 
sublimed lead as a pigment is about twenty-five years 
old, it is very likely, judging from its qualities, that it 
will be used more universally and in larger quantities 
in the future. 

When mixed with other pigments, such as zinc oxid, 
carbonate of lead, and the proper reducing materials 
added, such as silica^ clay, barium sulphate, etc., it pro- 
duces a most excellent paint, and at the seashore its 
wearing quality is superior to that of carbonate of lead. 
In composition it is fairly uniform. From the analyses 
of thirty-four samples of sublimed lead its composition 
may be quoted as 75 per cent lead sulphate, 20 per cent 
lead oxid, and 5 per cent zinc oxid, although each of 
these figures will vary slightly either way. Corroded 
white lead also varies in its percentage of hydroxid, but 




36 CHEMISTRY AND TECHNOLOGY OF PAINTS 

for analytical purposes a constant must be admitted 
which will fairly represent the composition. 

The question has arisen of late years whether sublimed 
lead is a mixture of the three components just cited, or 
whether it is a combination of lead sulphate and lead 
oxid with the mechanical addition of zinc oxid. Inas- 
much as all the lead oxids that are known in commerce 
or in chemistry are yellow, red, or brown it is held by 
many that the lead oxid 
of sublimed lead is really 
an oxysulphate, or, in 
other words, a basic sul- 
**■?*. "k",'' • ."'/' > •* i'' '!'*' pbate of lead. A mixture 
ti"'}'j'' .'••"V-** *f'\\^^ precipitated lead sul- 
*j.V I ■^. ■^'■,■""'.1 * j^-^.-V J phate, litharge, and zinc 
4j> -■.'■'»■ 'f"" ■*'.*■ **■"■;■**** white in approximately the 
^■g^",'-'"..'..* j-'-'uVV r^ proportions found in sub- 
^'■^ » »'-.^ '*V'"'*''*3^ limed kad, when ground 
* ■ .i *J ■"*■' v\^'' in oil and reduced to the 

' - ' " proper consistency, dries 

No. 4. SuBUMZD vvmTE LEAD-Pho- ^^J^^^ different from sub- 

tcimicrograph X2SO, showing great uni- 
formity of grain. limed whitc lead; in fact, 
sublimed lead when ground 
in raw linseed oil takes two days to dry dust free, but the 
mixture just cited will dry sufficiently hard for repaint- 
ing in twelve hours, because lead sulphate is a fair drier 
and lead oxid a powerful one. Yet the oxysulphate, hav- 
ing the- same composition, behaves totally differently from 
the mixture and in addition is of a different color. 

Under the microscope sublimed lead shows the 
absence of cr>'Stals and remarkable uniformity of grain. 
Being a much more inert chemical body than the other 
lead paints, it does not react on linseed oil, and there- 
fore makes a much more durable paint compound. It 



WHITE PIGMENTS 37 

has been urged that sublimed lead is not as susceptible 
to sulphur gases as white lead, but this the author 
has not been able to substantiate, for while it may take 
hydrogen sulphide a longer time to discolor it, it is 
simply a question of degree and it is acted upon by sul- 
phur gases, although not as quickly as white lead. 

Sublimed lead can be determined in a white mixed 
paint without any difficulty, owing to the estabKshed 
ratio between lead oxid and lead sulphate. The per- 
centage of free zinc sulphate in sublimed white lead 
varies from a trace to a half per cent, and many times a 
chemist will report more zinc sulphate than is actually 
present, because in washing or boiling a dry or extracted 
sample the lead sulphate may interact with the zinc 
oxid and show a larger percentage of zinc sulphate than 
is really present in the dry products before analysis. 

Sublimed white lead as a marine or ship paint is of 
much value, owing to its harcfiiess of drying and imper- 
viousness of film. 

Standard Zinc Lead White 

The ores utilized in the manufacture of this material 
are what are known in mining parlance as "Low Grade 
Complex Ore," originating in and about Leadville, Colo- 
rado; Low Grade, inasmuch as the gold, silver, and cop- 
per are present in quantities too small to warrant the 
excessive cost of refining. Naturally this ore contains 
varying percentages of zinc blende or sphalerite and 
Galena or native lead sulphide, and in order to furnish 
the product with the proper proportions of lead and zinc 
the ores are first analyzed, then mixed in their proper 
proportions, and volatilized at a heat of from 2200 to 
2500° F. In the volatile state it is carried to the com- 
bustion chamber, where the chemical transformation of 



38 CHEMISTRY AND TECHNOLOGY OF PAINTS 

the product, due to oxidation, completes itself. The 
white fume is collected in woolen bags, further oxidized 
on open-hearth furnaces, whitened, and then bolted. 

The pigment carries approximately 50 per cent pure 
zinc oxid and 50 per cent lead sulphate, which have 
combined at an intense heat in vapor form, the union 
being far more intimate than anything that could be 
obtained by mechanical means. 

This pigment was first 

.:.*J^^^^i^,it.s. P"*- "P**" ^^^ market 

]|:'^^'~i>^-^^/^V twenty-four years ago, and 



"•* '-r %i.. 




, Sta,\dard ZfN'c Lead Win 
rhotomicrograph X150. 



[ period not exceeding ten 
I years, and within the last 
' eight or ten years it had 
become more uniform and 
was regarded as a valu- 
able paint material by a 
great many mixed paint 
manufacturers. However, 
this material is at pres- 
ent not manufactured, but has been largely superseded 
by a white known as Ozark White, which will be de- 
scribed under that heading. 

The color, while it is not as white as zinc oxid, is 
about the same shade as the average corroded white 
lead. The pigment can be used to great advantage 
in combination leads, graded leads, primers, floor paints, 
and ready mLxed paints. Its specific gravity is approxi- 
mately 5.5, and its composition theoretically 50 per 
cent pure zinc oxid and 50 per cent lead sulphate. 
The pigment generally contains a trace of silica, iron, and 
alumina. A very small portion of the lead is in the 



WHITE PIGMENTS 39 

form of a basic lead sulphate, and the pigment un- 
doubtedly takes up a little moisture on standing. Its 
average analysis shows the following composition: 

PbS04 50.00 per cent 

ZnO 49-55 per cent 

ZnS04 0.40 per cent 

The percentage of zinc sulphate will vary slightly, 

but under normal conditions it will seldom average higher 

than ^ of I per cent, and where it does average more than 

this it is frequently due to long-continued boiling in the 

flask, which causes a reaction between lead sulphate and 

zinc oxid. 

Analyses of Standard Zinc Lead White 

PbSOi 48.90 50.00 49.22 49.80 50.15 48.87 

ZnO 50.50 49.55 50.41 49.90 49.25 50.82 

ZnS04 0.25 0.40 Trace 0.20 0.12 Trace 

Photomicrographs of zinc lead show a uniformity of 
grain, and microscopic investigations fail to show anything 
but a homogeneous product. It is very stable. When 
exposed to the air in a thin film, mixed- with a proper 
proportion of linseed oil and drier, it retains its gloss 
longer and chalks less than a similar film containing a 
mixture of 50 per cent corroded white lead and 50 per 
cent zinc oxid. Like white lead, it whitens on exposure, 
but holds up in suspension better, as indicated by its 
low specific gravity. When a paint is made on a zinc 
lead base ground in pure linseed oil it will not separate, 
form a cake, or yield a sediment; neither will it peel, 
chalk oflF, or turn yellow. 

Ozark White 

Ozark WTiite is a very desirable pigment and has all 
of the good qualities of Standard Zinc Lead White and 



40 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Sublimed White Lead. It is very largely used .in the 
manufacture of mixed paint. In many respects it is 
superior to the old Standard Zinc Lead White, because 
its approximate composition is 60 per cent of zinc oxid 
and ,40 per cent of lead sulphate. 

The process is so highly perfected that the manu- 
facturers can control the composition so as to insure a 
variation of not over 2 per cent, and with rare exceptions 
_ the material does not 

vary i per cent from the 
composition given. To 
attain this degree of uni- 
formity, a complete anal- 
->'.i'j y^s '^^ every car of ore 
*-■'-■ -^ is made as soon as it is 
received before passing it 
to the mechanical mixers. 
«..^. At the mixers another 
"^ analysis is made, and an 

ore higher in zinc or lead 

No. 6. Ozark White— Phoiomiciogniph ,, , > 

j(3oo. added, as the case may 

require, in order to have 
the proper metal constituents. The ore, after being 
mixed with the proper proportion of coal and antiflux- 
ing material {crushed silicious rock or mine screen- 
ings), is charged into furnaces which have pre\iously 
been bedded with a sufficient amount of coal to start 
combustion. The furnaces are then sealed, allowng the 
temperature to rise to about 2300° F., at which point 
it is held until the zinc and lead pass off together in the 
form of fume, which is conducted by means of suction 
fans through pipe-lines for a distance of about 500 feet, 
where it enters large brick bag houses. The fumes 
have by this time lost considerable of the heat, so that 




WHITE PIGMENTS 41 

they may be gathered into fabric bags, where the gases 
pass out and the pigment is collected. From the bag 
house the pigment is conveyed to an automatic packer 
and placed in barrels of suitable weight, and is then 
ready for the consumer. 

An actual chemical analysis of an average type cf 
Ozark White shows the following: 

ZnO 59-32 per cent 

PbS04 39.05 " " 

ZnS04 0.78 " " 

SO2 0.05 " " 

H2O... 0.66 " '' 

AS2Q8 0.12 " '' 

Total 99.98 per cent 

Zinc Oxid 

Formula, ZnO; Specific Gravity, 5.2 

Zinc oxid as a paint pigment is only sixty years old, 
and when it is taken into consideration that in that short 
space of time its use has grown until in 1905 nearly 
seventy thousand tons were used in the paint industry 
in the United States, it speaks for itself that the material 
must be of exceptional merit to have advanced so rapidly. 
At the same time, although it is impossible to obtain 
any exact figures on the subject, it is probable that 
more than one half of these seventy thousand tons was 
used in connection with other materials. 

The discovery of zinc oxid by Le Clair in France and 
Samuel T. Jones in America is sufficiently well knownti, 
and has been quite thoroughly written up in other books. 
The former made zinc oxid by subliming the metal; the 
latter made it by subliming Zincite and Franklinite ores. 
The specific gravity of zinc oxid wall average 5.2, and 
fifty pounds will take fifty pounds of linseed oil; in other 



42 CHEMISTRY AND TECHNOLOGY OF PAINTS 

words, to produce the proper mixed paint it will require 
a far greater proportion of linseed oil than white lead will 
take. It is generally stated in text-books that zinc 
oxid is not affected by sulphur gases and therefore 
will not turn color. This statement is not exactly 
correct; the author always contended that zinc oxid is 
not visibly affected by sulphur gases, but there is no 
doubt, as any chemist will admit, that zinc oxid is 
affected by sulphur gases, although not to the same 
extent as white lead. As zinc sulphide, zinc sulphite, 
and zinc sulphate are white products, the absorption is 
not evident to the eye, and hence the erroneous state- 
ment has cjept into use that zinc oxid is not affected 
by sulphur gases. 

When mixed with linseed oil and the proper amount 
of drier, it sets and dries much more slowly than white 
lead. Nevertheless this drying continues in the form of 
progressive oxidation until the surface becomes very hard. 
A comparison between zinc-oxid and white-lead paints 
will show that the progressive oxidation which takes 
place when white lead dries produces a chalky mixture, 
while the reverse is true of zinc oxid, which will produce 
a hard and brittle vitreous surface which is somewhat 
affected by temperature changes. Owing, therefore, to 
the diverse effects of the two pigments, a combination 
of lead and zinc is often well recommended. The hard 
drying zinc has not, however, been very well understood. 
Fifteen years ago the author undertook a series of exp)eri- 
ments and found that the drier was very largely respon- 
sible for the hardening action of zinc. If the linseed 
oil be prepared with litharge (PbO), the resulting zinc 
paint will last far longer and be much more flexible and 
consequently not readily cracked when exposed to a 
variation of temperature of even 130° F., such as we have 



f- 



WHITE PIGMENTS 43 

in this climate. If, however, a drier is used in which 
manganese (MnOi) and red lead (PbiO«) have been cooked 
with the oil, the action of the manganese continues until 
a \itreous surface is the result. It is owing to the result 
of these investigations that the use of American zinc 
oxid'made from Franklinite ore has become so general 
for the manufacture of white table oilcloths. (See 
Journal of Society of Chemical Industry, No. 2, Vol. 
XXI, Jan. 31, 1902.) 

UTien enamel paints 
are made of an oil var- 
nish and zinc oxid, and 
the drier in the varnish 
is composed of manga- 
nese and lead, the enamels 
eventually become hard, 
exidently through the cata- 
lytic action of the man- 
ganese. It is desirable to 
omit the manganese ^ in 
high grade enamels, or, 
where manganese must be 
used in order to obtain 
a rapid setting, the borate of manganese should be 
employed, but only in very small quantities. 

The American zincs are: 

First. The Florence Red and Green Seal zincs, which 
are made by the sublimation of the metal and are prac- 
tically pure and equal in all respects to those made in 
France and Belgium. 

Second. The New Jersey zinc oxids, which are made 
from Franklinite ore and are free from lead and fre- 
quently run over 99 per cent ZnO. 

Third. Mineral Point zinc, which is made at Mineral 



No. 7. Americ.v-v Zi.vc Oxid — Photo- 
micrograph xjoo, very pure and very 
uniform in gi^in; this oxid is made 
direct from the ore. 



44 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



Point, Wisconsin, and contains from 2 to 4 per cent of 
lead sulphate. 

Fourth. The leaded zincs made in Missouri, which 
contain from 4 to 10 per cent of sulphate of lead. 

Zinc oxid chalks to some extent in the same manner 
as white lead, but only if the atmosphere is charged with 
carbon dioxid or salt. The same experiment which was 
carried out with white 
lead in order to show its 
solubility in a solution of 
carbon dioxid was carried 
I out with zinc oxid and 
1 the same result obtained. 
I Much weight cannot be 
given to these experi- 
ments, because these chemi=. 
cals are not always present 
in the atmosphere. They 
are merely chemical results 
which demonstrate both 
the cause and effect, but 
it is of some interest to 
know why the paint films perish. The zinc oxids made 
from western ores are slightly more permanent than 
those made from the New Jersey ores, and as paint 
materials they possess the advantage of containing a 
larger quantity of lead sulphate. 

Nearly all zincs contain a small percentage of zinc 
sulphate. Much unnecessary trouble has been caused 
by the criticism against zinc sulphate. Where a paint 
contains moisture or where water is added in a very 
small amount to a heavy paint in order to prevent it 
from settling, and not more than one per cent of actual 
water is contained in the paint, zinc sulphate forms an 




No. 8. French Gaeen Seal Oxid — 
Photomicrograph xjoo, much whiter 
than the American zinc made from the 
metal, but coarser in grain. 



WHITE PIGMENTS 45 

excellent drier, particularly where it is desirable to make 
shades which contain lampblack. The outcry against 
zinc sulphate is unwarranted, because as much as 5 per 
cent is used in making a patent drier. The amount of 
zinc sulphate, however, in most of the dry zinc pigments 
probably decreases with age. Zinc oxid or other zinc 
paint which will assay i per cent of zinc sulphate will, 
when kept in storage for six months, show a decrease in 
the zinc sulphate to one half of i per cent. 

In the enamel paints the presence of zinc sulphate is 
not a detriment, and in floor paints it might be con- 
sidered as a slight advantage, for it aids in the drying 
and hardening. However, too much of the soluble salt 
is never to be recommended.' 

ZiNOX 

This is a hydrated oxid of zinc not manufactured in 
this country, but made and used almost entirely in 
France. It is not yet sold dry, but generally sold either 
in the form of a ready mixed enamel or in a semi-paste 
form, and is presumed to possess advantages over zinc 
oxid. From experiments which the author made it has 
been found that the hiding power and working quality 
are practically the same as that of zinc oxid. It pos- 
sesses, therefore, no marked advantage over a zinc oxid 
enamel, although it is stated that it remains in sus- 
pension longer than any other pigment. The zinc oxid 
enamels all remain in suspension a very long time, and 
even though they settle they do not settle very hard and 
can be very easily stirred. In thinner media, such as 
are used for the manufacture of flat wall paints, the 
hydroxid of zinc has some advantage over the oxid, as it 
produces a paint that remains in suspension longer and 
is more ready for use than that made from the oxid. 



46 CHEMISTRY AND TECHNOLOGY OF PAINTS 

LlTHOPONE 

Synon\Tii : Oleum White, Beckton White, Charlton White, Pono- 

lith, Jersey Lily White, Orr's WTiite 

Chemical Formula, ZnS + BaS04; Specific Gravity, 4.2 

When solutions of zinc sulphate and barium sulphide 
are mixed together in molecular proportions a heavy 
flocculent precipitate is formed according to the following 
reaction : ZnS04 + Aq + BaS + Aq = ZnS + BaSO* + H2O. 
The theoretical percentage mil be about 29^ per cent 
zinc sulphide and 70^ per cent barium sulphate. This 
precipitate as such has no body or covermg power, and 
when washed and dried is totally unfit for paint pur- 
poses; but John B. Orr, of England, in 1880 discovered 
that when it is heated to dull redness, suddenly plimged 
into water, ground in its pulp state, thoroughly washed 
and dried, its characteristics are totally changed, and it 
makes a very eiTcctive and durable pigment for paint 
purposes. In the first place, it is then a brilliant white; 
in the second place, it is extremely fine in texture; and 
in the third place, it has more hiding power than pure 
zinc oxid. Owing to its chemical composition it is 
stable in every medium kno^\^l for paint purposes, except- 
ing those which are highly acid. It took several years 
to perfect the manufacture of lithopone, but it may be 
easily said that at the present time lithopone is made 
with great uniformity and has valuable properties, as 
will hereinafter be shown. 

The method of manufacture is quite simple, success 
depending very largely on the purity of certain materials. 
It is worthy of mention, however, that the average chem- 
ist unfamiliar with both the theory and practice of its 
manufacture cannot make it successfullv. In the first 
place, solutions of barium sulphide and zinc sulphate of 



WHITE PIGMENTS 47 

known composition must be made. The fact that they 
are impure has no effect on the ultimate product, provided 
the chemist knows the impurities he has to deal with 
and the simple methods for their elimmation. For 
instance, the zinc sulphate must be free from iron or a 
yellowish product is the result. The solutions must be 
standardized for each batch. The impurities can be 
eliminated during the process of manufacture, or, more 
properly speaking, before they are pumped into the pre- 
cipitation tub. 

The barium sulphide, however, is quite pure, for the 
reason that metals like copper, iron, and manganese 
which are likely to be 
present, form insoluble £ 
phides. Barium i 
made by heating 1 
(BaSO*) to dull redness .-^^ 
with coal, petroleum re- •^■. »^;^S''' ■^i^---rC^'H^^>^ 
siduum, pitch, sawdust, or ;y^^"^-i-^A-l:^^^\'4v^ 
other materials having a vE'^^iS^^S^'^^L'?^'^'? 
high percentage of carbon. ^^^^Jj|^?;>i*i!*^^l^' 
The resulting reaction may 
be represented by the 
following equation: BaSOi no. g. Lithopose (dry) — Phoiomi- 

+ 4C = BaS + 4CO, al- crogiaph X2SO, exceedingly fine and 
., , , . uniform in grain. 

though under many cir- 
cumstances the reaction is more slightly complicated. 
After the reaction is completed and before the air can 
have any influence on the sulphide, the mass is digested 
in vats and filtered; when the solution reaches a density 
of 17°, Baum€ long, yellowish, needle-shaped crj'stals 
separate from the mother liquor. These crj'stals are 
almost chemically pure barium sulphide. 

With the proper concentration of the solutions, proper 




48 CEEUISTRY AND TECBNOWGV OF PAINTS 

temperature and speed at which the two solutions are 
poured together, the resulting precipitate will be of such 
ph>sical characteristics that it can be most easily filtered 
and dried. It is then placed in muffles and heated above 
920° Fahrenheit, suddenly plunged into water, again 
ground, washed, and dried. It is then ready for the mar- 
ket. The overheating of the precipitate decomposes some 
of the zinc sidphide and converts it into zinc oxid. All 
of the earlier manufacturers overheated their product, and 
that is the reason why litho- 
pone formerly contained 
from 5 to 10 per cent zinc 
oxid, whereas theoretically 
1 it should have contained 
none. The manufacturers 
I of the present day, however, 
have overcome all these dif- 
ficulties, so that a remark- 
ably uniform product is 
obtained, the percentage of 
No. 10. LiTHOPovK (ground in oil) — zinc oxid being small indeed. 
[■ii.>i.mii.Togni|>h xijo, cMccdingiy \\rg jj^ve here an excel- 
lent example, as has been 
staled under another chapter, of a pigment containing 70 
per cent barium sulphate, which may be regarded as 
pLTfc'cUy pure and normal, and yet twenty-five years 
agi) any ])ignu'nt containing far less barium sulphate 
Ihaii lithopone would have been regarded as adulterated. 
\ii man ran reasonably state that barium sulphate is an 
adullcrant to lithopone, for the obvious reason that it is 
a constilucnt jKirt of the pigment. 

Lithopone has gone through many vicissitudes; no 
pigment has been blackguarded quite as much as this, 
and yet no pigment has survived its condemnation as 




WHITE PIGMENTS 49 

well as this. Almost every paint manufacturer in the 
United States finds some excellent use for it. Within 
the last seven or eight years lithopone has come into its 
own, and today there is no paint manufacturer in the 
United States, to the best of the author's knowledge, 
who does not use this material. Ten years ago very 
few paint manufacturers used it at all. 

Since 1906 riiany chemists, including such capable 
men as Professor Ostwald, have attempted to find the 
cause of the darkening of lithopone in sunlight. WTien 
night comes a change takes place, and the foUowdng 
morning lithopone is as white as it ever was. This 
proj>erty is called the "photogenic'' quality. This photo- 
genic action goes on continually, and there have been 
a large number of investigators who have attempted to 
overcome this, and a review of the literature shows that 
most of the methods, with two or three exceptions, have 
been empirical. It has remained, however, for Professor 
W. D. Bancroft of Cornell University to delegate one 
of his students, W. J. O'Brien, to make these investiga- 
tions, and the full account is recorded in Volume XIX 
of the Journal of Physical Chemistry, 113-44 (1915); 
an extract is herewith given of the phenomenon. 

That the darkening in sunlight is due to the formation 
of zinc from zinc sulphide was shownn by the fact that 
the dark product reduced ferric alum, as showTi by the 
api>earance of a blue color with potassium ferricyanide, 
and that it is readily soluble in acetic acid, in alka- 
lies, and in solutions of sodium chloride and sodium sul- 
phate. The zinc is a direct product of the action of light on 
zinc sulphide. The results of the investigation are sum- 
marized as follows: Quenching in water prevents further 
oxidation of the red-hot zinc sulphide. It also disinte- 
grates the semi-fused mass and dissolves out most of the 



50 CHEMISTRY AND TECHNOLOGY OP PAINTS 

soluble salts. Heating the barium sulphate-zinc sulphide 
precipitate is necessary to dehydrate the zinc sulphide 
and to change its physical condition, so that it forms a 
dense mass wdth good body which can be ground more 
readily. The yellow color produced on overheating is 
due to an oxid film, as was shown by Famau. The 
darkening of lithopone is not due to impurities such as 
iron, lead, cadmium, etc. The presence of salts which 
form soluble zinc salts, such as sodium chloride, sodium 
sulphate, etc., accelerates the darkening of the lithopone. 
These salts dissolve away the zinc oxid film. This is simi- 
lar to the behavior of magnesium in water. Magnesium 
does not decompose water very readily at ordinary 
temperatures. In the presence of magnesium chloride, 
however, the action takes place vigorously. The pres- 
ence of salts which form insoluble zinc salts, such as the 
alkaline phosphates, bicarbonates, ferrocyanides, and bo- 
rates, retards or prevents the darkening of lithopone. The 
action of light on the zinc sulphide is a reducing one, 
hydrogen sulphide and metallic zinc being formed. The 
reaction is not a reversible one; the metallic zinc formed 
is oxidized to zinc oxid; barium sulphate is not neces- 
sary for the darkening of the zinp sulphide. Heating the 
zinc sulphide is not necessary to get it to darken, al- 
though heating makes the zinc sulphide more sensitive 
to light, probably because the reducing atmosphere and 
the sodium chloride used remove the zinc film more 
readily. The zinc oxid film can be removed by boiling 
in a concentrated solution of zinc chloride. The zinc 
suli)hide so treated will darken in the presence of a 
reducing agent. When barium sulphate is precipitated 
with the zinc sulphide, it aids the darkening, due to the 
fact that it adsorbs the zinc sulphide, thereby giving 
increased surface exposure of the zinc sulphide. It 



WHITE PIGMENTS $1 

probably also 'adsorbs the metallic zinc. The zinc sul- 
phide will darken without the presence of a reducing 
agent if it is precipitated with barium sulphide and 
boiled in a concentrated solution of zinc chloride. The 
barium sulphate probably adsorbs metallic zinc as well 
as zinc sulphide, thus making the latter sensitive to 
light. The patented processes for the prevention of the 
darkening of lithopone depend upon the formation of an 
insoluble film around the zinc sulphide. It is impossible 
to make a lithopone that will not darken unless there is a 
film protection of some kind over the zinc sulphide. A 
lithopone of good quality that would not darken was 
made by producing an oxid film on the zinc sulphide and 
keeping the oxid content above 3 per cent and below 5 
per cent. Aluminium oxid can be substituted for the 
zinc oxid. A film of sulphur protects to some extent; 
no experiments were made to determine the maximum 
efficiency possible. 

From the above we can readily see that the theor>' is 
a tenable one, and that the action of light on zinc sul- 
phide is a reducing one, sulphuretted hydrogen and 
metallic zinc being formed. Metallic zinc is again con- 
verted into zinc oxid, and the color of the metallic zinc 
mixed with the other bases gives the gray shade that is 
apparent. The manufacture of a lithopone, therefore, 
that would not darken, by producing an oxid film and 
keeping the oxid content above 3 and below 5 per 
cent, would have its disadvantages, for in a rosin var- 
nish or an acid resin varnish livering would eventually 
take place, and one of the principal features of lithopone 
has been that an acid resin or rosin varnish could be 
used and no chemical reaction would take place. 

The large use of lithopone today is for flat wall paints, 
for it can be mixed with the China wood oil-rosin var- 



52 CHEMISTRY AND TECHNOLOGY OF PAINTS 

nishes without the danger of livering or hardening, and 
it has every advantage as far as hiding power and freedom 
from mechanical defects that white lead and zinc oxid 
have, with the added advantage of being non-poisonous 
(although the danger of using a poisonous material on a 
wall is largely overestimated). Lithopone is likewise 
very largely used in the cheaper grades of enamel paints. 
As an interior white, a first coat white, or as a pigment 
in the lighter shades for floor paints, lithopone cannot be 
excelled for its body, durability, hardness, fineness of 
grain, and ease of application. It does not oxidize 
progressively, and this single feature has made it inval- 
uable to the table oilcloth and floor oilcloth industry 
throughout the world. Its indiscriminate use, however, 
is not to be recommended, and the paint chemist should 
be permitted to decide when its value is the greatest. 
As a marine interior paint, either as a first coat or for 
making neutral paints where other whites would be nec- 
essary, it is found to outlast both zinc oxid and lead 
carbonate. 



CHAPTER III 

The Oxids of Lead 

« 

The oxids of lead used in making mixed paints are 
principally litharge, which is PbO, and red lead or orange 
mineral, Pb304. 

Litharge 

Chemical Formula, PbO; Specific Gravity, 9.2 to 9.5 

Litharge is the first oxid of lead; that is to say, when 
lead is melted and heated in a current of air the first oxid 
produced is the PbO, yellow in color, and known as 
litharge. Verj"^ pure litharge has the color of pale ochre. 

Litharge in the manufacture of preservative paints 
has excellent protective qualities, because it is basic and 
resists corrosion. Furthermore, litharge and linseed oil 
make a very hard cementitious film which withstands 
abrasion, but unfortunately litharge combines wdth lin- 
seed oil so rapidly that when used in mixed paints to 
any great extent it tends to "liver'' and saponify. On 
the other hand, a number of black paints which are 
composed of lampblack, carbon black, charcoal, or a mix- 
ture of these, are held together by the use of litharge, and 
where these paints are used within a month or two after 
they are made they serve their purpose perfectly. 

Litharge is soluble in acetic acid, and the other 
impurities in it are generally insoluble, so that a very 
rapid test can be made from the paint manufacturer's 
point of view by simply boiling in acetic acid. Litharge 
varies in texture under the microscope, as is shown in 
the accompanying photomicrographs. 

53 



•* 
\ 



54 CHEMISTRY AND TBCHSOLOGY OF PAINTS 

Flake litharge is generally used by varnish makers or 
oil boilers for making drying oil, but the more finely 
powdered forms of litharge have a peculiar construction, 
and when the litharge is impure and contains metallic 
lead and red lead it is distinctly noticeable under the 
microscope. 

Red Lead 
Chemical Formula, PbjOi; Specific Gravity, q.o 

Red lead is a very heavy orange-red pigment, more or 
less crystalline in structure. It is prej)ared by heating 
litharge lo a temperature of 600° to 700° F. 

^. ^^,. ^ Owing to the conditions 

^:'y'-^^''''^^.''^- ,. under which it is made it 

'v ;' * V-' , contains from a trace to 

'^^ ■ ,'., ' *\^ an appreciable percentage 

' ' ■ *^kk '^^ litharge (PbO), and 

_■-'•'' '"^h when used for pdnt pur- 

,r ; . -...^^.t^ poses it cannot be said 

■ '" .' Vi' ^^^^ ^ small content of 

■ ^ _ , ,,' - t ■ :, -'J' litharge does any harm. 

'V^''*--y.»V*''^'*&'V':' When prepared in linseed 

"^■**SvV^*' ' °^' '' '""^'^ ^^ freshly used, 

otherwise it forms a dis- 

Nm. I ] . !.iTiiAKi;i. - I'liiitomicniirraiih xioo. . ... - i i. 

tinct combmation with hn- 
scf'l oil and bt'comos hard and unfit for use. In its 
pli\si(al charaiifristicrt it can be compared Mith plaster 
nf pjuis. Il ails \cry much like jjlaster of paris when 
m'wvA with walcr. Once set, il may be reground and will 
iic\»T j^el anii'ii- T^ use as a priming coat for structural 
sitcl li;is been ennrmous, but engineers who have studied 
llu' subjcrl liavc fume to the conclusion that there are 
olliiT nuilcrials just as good, or better, which are easier 
to upply and <tn not possess the characteristic difficulties 



TEE OXIDS OF LEAD 55 

of application. The author has made many investigations 
on this subject, and for further detail would refer the reader 
to the Journal of the Society of Chemical Industry, 
Vol. XXI, January, 1902, and Vol. XXIV, May, 1905. 

There are some manufacturers in the United States 
who make red lead from litharge and use nitrite of soda 
as an oxidizing material, and in the manufacture of this 
tj-pe of red lead carelessness in manufacture will result 
in a fairly large percentage of caustic soda remaining in 
the red lead. Caustic soda finds its way frequently into 
Utharge when it is made 
by what is known as the c ' t.j^J^'i 

nitrate process, in which 
nitrate of soda and me 
tallic lead are fused to '*alI^*Vi?J^^'5?i 
gether, jielding an oxid of *^^,J^^^'' 
lead, PbO, and nitrite of ^^ tf^ "^^ -j 
soda, NaNOj.' Red lead '5i'.Jlv 
manufactured by this pro- ^Ipj 
cess will usually contain a 
small amount of caustic ^^w*,/ 

soda and nitrite of soda .^ , ''^*~ 

No 13 Litharge — Photom crograph X300 
and such red lead, al 

though otherwise pure, makes a very poor paint, because 
the caustic soda saponifies the linseed oil, and exposure 
to weather of a few months will turn the red lead white 
or pinkish white and make it very soluble in rain water. 
Rust is also rapidly produced under such red lead, and 
therefore in specifying red lead it is well for the engi- 
neer to insert a clause that an aqueous mixture of red 
lead shall show no reaction with phenolphthalein. 

Within the last five years a great improvement has 
been made in the manufacture of red lead, and this 
' See Holly's "Analyas of Paint and Varnish," p. 221. 




56 CHEMISTRY AND TECHNOLOGY OF PAINTS 

improved form has been known as Dutch Boy Red Lead, 
which is practically a chemically pure Pb804. Pure red 
lead was the one material which had never been sold either 
ground in oil or ready for use, owing to the fact that the 
large content of litharge combined with the fatty acid 
of the oil and the glycerine and formed a lead soap. It' 
is well known that litharge cement, used for many pur- 
poses around a factory, is litharge and glycerine, which 
sets up hard wdthin an hour and forms a vitreous product. 
It is also well known that when linseed oil is neutralized 
with caustic soda, and the resulting linoleate of soda 
soap filtered out, a ready mixed or semi-paste red lead 
can l:)c made which will remain soft for many months, 
l)Ul the proprietary' brand of red lead just referred to 
nitinufactured by the National Lead Company, is a pure 
red lead similar in composition to orange mineral, which 
remains soft and produces a paint that has many advan- 
tages over the old-fashioned red lead. 

Many engineers and shipbuilders prefer to use dry 
red lead, and a proper specification for dry red lead 
should be one that will contain the minimum amount 
of litharge. 

It cannot be denied that red lead is one of the best 
priniing materials that we have, but under no circum- 
'.L'liKcs sliould less than 28 lbs. of dry red lead be mixed 
vvilh one ^mIIoh of linseed oil. Many of the bad efifects 
;mr| faihires of red lead are not due to the lead itself, 
hill lo 1)11(1 a])i)licati()n and insufficient dry materials. 
A. ;i mailer of fad, the best results with red lead are 
oLi.iinrrI (iu tlie author's experience) by using 33 lbs. 
.11 'I our ;«;allon of linseed oil. To this oil may be added 
ni,i hall |)inl of any good Japan drier. 

A . a iifiniin^ coat red lead possesses excellent pre- 
.1 i ;iiiv<' ^jualilies, providing it be properly applied wdthin 



THE OX IDS OF LEAD 



57 



a reasonable time. If red lead be used in the proportion 
of 17 lbs. to one gallon of linseed oil it forms a ver>' poor 
coating on account of the separation of the pigment 
from the oil, particularly on a vertical surface. In a 
pamphlet published by a manufacturer a large number of 
precautions were given to the consumer for the prepara- 
tion of red lead as a priming coat, the neglect of any 
one of which might produce failure for the paint. As a 
prominent engineer remarked, he did not care to specify 
a paint in which there 
were seventeen chances 
of its failure due to a 
possible faUibility of hu- 
man nature. The use of 
a drj' pigment mixed with 
oil and applied within one 
hour of its mixture is con- 
trary to the progress of 
the present day, when 
paints finely ground by 
machinery are taking the 
place of all others. A dry 
pigment stirred by hand 
in a pail of oU carries with it a large number of air 
bubbles which become encysted and carry oxj-gen 
and other gases to the surface to be protected. The 
engineer should, therefore, not specify that a paint be 
made entirely of red lead and linseed oil and sent ready 
for use to the place of application when such specifica- 
tions cannot be reasonably executed. On the other 
hand, where red lead is specified the engineer or paint 
manufacturer who can supply a material containing 
between 40 and 50 per cent red lead and 50 and 60 
per cent inert base is deUvering a far better article, 




No. 13. French Oraxce Mi.vehal 
Photomicrograph xijo, not vcr>' » 
form in grain. 



5$ CHEMISTRY AND TECHNOLOGY OP PAINTS 

which can be more easily applied than the undiluted red- 
lead alone. 

The author made a large number of experiments on 
red lead mixed with linseed oil containing a small per- 
centage of drier, applying these mixtures to steel. The 
mixture was first appUed the moment it was thinned, and 
then at short intervals, up to the moment the red lead 
began to combine with linseed oil so as to make it 
impossible to handle the brush. The results of the experi- 
ment showed that freshly 
applied red lead was not 
as good as it was if applied 
one hour after it was mixed. 
The paint with which these 
experiments were made con- 
tained 24 lbs. red lead to 
one gallon of paint, which is 
approximately equal to 33 
lbs. dry red lead to one 
gallon of oil. The difficulty 
No. 14. Red l>u> - Ph.>.™i<ro«r.ph >" handling pamt of this 
xjoo of paint iiim frcsUy applied, kind Is vcry gieat, owing 

sliowing separation of . the pigment j^ jhg gxcessivc Weight of 
from the oil. , . . , , , 

the pamt as earned by the 
brush. Structural iron painters aU complain that muscular 
fatigue ensues where undiluted red lead is used, and when 
the inspector is not watching they will surreptitiously 
add an excessive quantity of oil, or volatile thinner, 
in order to lighten their labor, and for this reason red 
lead has frequently failed, when as a matter of fact it 
would have proved a perfect success had the original 
siK'cifications been adhered to. On the other hand, there 
should be no need of using a protective paint involving 
such great difficulties when there are dozens of others 




THE OX IDS OF LEAD 59 

that are as good, not only from the standpoint of pro- 
tective influence but also on account of the ease of 
mechanical application. 

It has been mentioned by many writers that one of the 
serious defects of red lead is the ease with which it is 
attacked by sulphur gases, but this objection does not 
hold good where it is properly and quickly coated over 
with a protective coat of the bituminous class. That 
red lead in its pure or concentrated state is not as good 
as a paint containing a solid 
diluent has been shown time 
and again where silica, 
lampblack, graphite, silicate 
of alumina, and such lighter 
pigments were mixed with 
it. Its extraordinarily high 
specific gravity is very much 
against its use as a paint, 
but if a mixture of one 
pound red lead and one 
pound wood black is taken ,, -c , ... 

' No. 15, Ked Lead — I iiotomicrograph 

the average specific gravity xiso, applied one hour after miMng, 

of the two is equal to that ^''"*"*"e separation and air bcUa en- 

, . . 1 T 1. cysted in film. 

of zmc oxid. Its spreadmg 

and lasting power is increased, so that a mixture of 
this Idnd is equal to a mixture of any of the good pre- 
pared paints for structural steel. Two large exposure 
tests made by the author in 1899 and examined in 1905 
showed that a mixture of 50 per cent red lead and 
50 per cent graphite ground fine and mixed in a pure 
linseed oil containing 5 per cent of lead drier wore almost 
as well as a mixture of 75 per cent Fe^Oj (ferric oxid), 
20 p>er cent silica, and 5 per cent calcium carbonate. 
The former paint, when the hand was rubbed over it, 




6o CHEMISTRY AND. TECHNOLOGY OF PAINTS 

showed slightly more destruction of the oil, the graphite 
giving a stove polish eflfect on the hand. The latter 
paint also showed a very slight stain on the hand, but not 
quite as marked as the former. The metal underneath 
both was in a good state of preservation, three coats of 
paint having been applied. The exposure was made 
on a slanting roof in New York City. 

Red lead has had the great advantage of having been 
the first protective paint ever used, for years no better 
paint being known. In this respect it is analogous to 
white lead. Much of the good reputation of white lead 
is due to the fact that for centuries there was no other 
white paint, consequently no comparison could be made. 
It must be borne in mind that all these experimental 
researches concerning red lead are based on very fine red 
lead, and no consideration is given to the detrimental 
reports concerning red lead due to the fact that it was 
improperly made and coarse. 

A laboratory test of red lead always shows up remark- 
ably well. A steel saucer painted with red lead in the 
laboratory will demonstrate that this pigment is superior 
to many others, but a field test of material made accord- 
ing to a laboratory" formula and applied on several tons 
of steel will generally show the opposite, for the obvious 
reason that in the laboratory a small test is usually 
carefully applied and little exertion is necessary, either 
with the mixing of material or for its application. The 
temperature conditions of the laboratory being normal, 
the person who mixes the paint usually scrutinizes the 
result carefully. On the other hand, in the field or at 
the shop a brush is used which will do the greatest 
amount of covering \\ith the least amount of exertion. 
The mixture may not be made by the best possible for- 
mula, and, if it is, more thinning material is generally 



THE OX IDS OF LEAD 6 1 

added until it works freely. The vertical part of the 
surface ^\dll, on account of its position, be more difficult 
to cover, and the paint will sag or run from it; whereas, 
the flat plate or saucer-shaped cup used in the laboratory 
holds the material in place by virtue of its position. 

Blue Lead 

In the sublimation of Galena a peculiar sulphide of 
lead is produced, which has been known commercially 
as blue lead, on account of its blue-gray appearance. 
This product has been on the market for several years. 
The contention is that sulphur fumes do not affect it as 
they affect red lead. As a priming coat it has been well 
spoken of. Its composition is as follows: 

Carbon 2.25 1.73 

Lead Sulphate 52.92 49-79 

Lead Sulphite 36 1.44 

Lead Sulphide 4.55 4.93 

Lead Oxid 37-48 4i-34 

Zinc Oxid 2.45 i.oo 

100.01 ICX).23 

No truly representative analysis of this material can 
be given, owing to the variation in the amount of sul- 
phate, sulphite, and sulphide. The material is not very 
fine; in fact, it contains an appreciable amount of grit, 
which, however, is removed in the second grinding. 

The pigment is not permanent to light, but in all 
probability this change in its tone is due to a chemical 
rather than to a physical decomposition. 



CHAPTER IV 



The Red Pigments 



The red pigments used in the manufacture of mixed 
paints are principally the oxids of iron, the red oxids 
of lead, and the permanent vermilions. No space will 
be devoted to the sulphide of mercury (quicksilver ver- 
milions), as the use of these materials has been super- 
seded entirely by aniline or para-nitraniline vermilion. 
Likewise no attention will be paid to the sulphide of an- 
timony reds, as they are obsolete in paint manufacturing. 

iVmong all the red pigments in the paint industry 
the oxids of iron take the lead as by far the most useful. 
Several years ago the author called attention to the fact 
that various forms of ferric oxid having the formula 
Fe203 could be used as rubber pigments. The sulphur 
used in the vulcanizing of rubber had no eflfect on the 
ferric oxid, no sulphide of iron being formed in the com- 
bination. On investigation it was found that some forms 
of ferric oxid are remarkably stable in composition, acting 
in many regards like a spinel. Exhaustive tests made 
with some of the ferric oxids used as paints for the pro- 
tection of steel and iron show that they are far superior 
to red lead and to graphite as paint protectives, being 
midway between the two in specific gravity. A mixture 
of graphite and ferric oxid (containing 75 per cent Fe208 
and 25 per cent silica) outlasted graphite by two years 
and red lead by three years. These tests were made on 

horizontal roofs, and eliminating the question of the cost 

62 



THE RED PIGMENTS 63 

of the paints, the ferric oxid stood the test and was the 
cheapest in the end. No argument can be adduced that 
ferric oxid is a carrier of oxygen, for it is a complete 
chemical compound, is not readily acted upon by dilute 
acids, not affected by alkalis nor by sulphur gases, and 
as a paint the author has not been able to demonstrate 
that it reacts on linseed oil. 

All of these arguments refer, of course, to a ferric 
oxid of known purity and definite composition either as 
pure Fe203 or as Fe203 containing 25 per cent of silica. 
In the course of its manufacture from the waste products 
of wire mills, for instance, or direct from ferrous sulphate, 
the processes being analogous, there is a likelihood that 
a small percentage of free sulphuric acid may cling 
mechanically to the substance. A good sample boiled 
with water and tested wdth methyl orange wall demon- 
strate this defect. It is wise, therefore, under all cir- 
cumstances to add up to 5 per cent calcium carbonate 
in any or all of these ferric oxid paints. There is, how- 
ever, another ferric oxid made from Persian ore. Over 
one hundred analyses of this ore in the laboratory of the 
author have shown that its composition will not vary 
more than 2 per cent either way, it being 75 per cent 
FciOi and 25 per cent Si02. 



Venetian Reds 

Venetian reds have sometimes been described as burnt 
ochres, but this definition of the Venetian reds is incor- 
rect. The generally accepted composition of the Venetian 
red is a combination of ferric oxid and calcium sulphate, 
in which the ferric oxid wiU run from 20 to 40 per cent, 
and the caldimi sulphate from 60 to 80 per cent. When 
ferrous sulphate is heated with lime an interchange or 




64 CHEMISTRY AND TECHNOLOGY OF PAINTS 

reaction takes place, the sulphuric acid of the copperas 
going to the lime while an oxidation of the iron takes 
place. Another method known as the wet method is 
the direct reaction between ferrous sulphate and wet 
slacked lime. 

\^enetian red has been known as a paint pigment for 
upwards of a centur>', and while theory would indicate 
that it is by no means as desirable a pigment to use as 
other mixtures of ferric oxid, it must be apparent that 

-— j*^.^^^^ in view of the fact that it 

^^•; ^m^ • ^^\ ^^^ given general satisfac- 

s* ^^H^S^^^ A. ^^^^ ^' ^^ ^^ ^^ means as 

/ . ^^ ' j%- - f ^P^ undesirable a pigment as 

' ■ i/h ■• •■-"* K' \ chemists indicate. Theten- 

-^ ' ^;- » ;' ^ 'I dency, however, at the 

%* -> ^ ** • ^ ^f present time is for manu- 

^ , > / facturers to buy strong 

pure oxids and reduce 
them with other inert 
fillers, for the principal 

No. i6. En(;lisii \'i:netian- Red — reason that a Venetian red 
Photomicrograph X250, showing cai- carrying a high percentage 

cium suli)hate crystals. r 1 • 1 i_ x j 

of calcmm sulphate and an 
unknown quantity of water or moisture tends to become 
hard in the package, whereas the mixtures of known 
composition remain soft for many years. Venetian reds 
arc all of the familiar brick color shade, the color of 
bricks being caused by the same pigment as the one that 
gives the color to Venetian red. 

Indian Red 

This is supposed to have been named by Benjamin 
West, a celebrated American artist who lived more than 
a century ago, and who as a boy used a few primary 




THE RED PIGMENTS 65 

earth colors as pigments for paint. One of these was a 
natural hematite, and he observed that the Indians used 
this for painting their faces. The name is also supposed 
to have had its origin in the fact that "Persian Gulf 
Ore," which was found in the Orient, was exported to 
England under the name of "East Indian Red." This 
Persian Gulf Ore is likewise a hematite, and later on a 
similar ore was found in parts of England which, when 
mined, looked very much like coal, but when crushed and 
ground in water turned 
a deep blood-red. The 
old name for this mineral 
is still "blood-stone," and 
some very fine specimens 
of this mineral are still 
mined in England in con- 
junction with beautiful 
quartz crystals, so that 
we find in England a care- 
ful selection. 

The native Indian red no. 17. auemcw Venetian red- 




Will run 90 per cent FCjOj, Photomicrograi)h x»5o. showing fine 
, , grains of calcium sulphate. 

the American 88 per cent, 

and the Persian 75 per cent, the balance in every case 
being silica. The Indian red of commerce, however, is 
an artificial product made like the base of the Venetian 
red by calcining copperas and selecting the product as 
to shade. There is no pigment, with possibly the excep- 
tion of lithopone and artificial barium sulphate, which will 
approach Indian red in fineness of grain. The prices 
which a fine, pure Indian red or ferric oxid of any shade 
will command are most remarkable, many tons being sold 
e\-ery year in large quantities at as high a price as fifty 
cents per pound and used entirely for polishing gold, 



66 CHEMISTRY AXD TECllXOLOCY OF P.ilXTS 

sil\er, and other metals. The well-known "watch-case 

rouge" is nothing but pure Indian red which has been 

ground, washed, and treated mechanically with so much 

care that three-cjuarters of its selling price is repre- 

i| . ^ sented in the labor of manip- 

V^-fc, ■ -^ \' : - ulation. If, therefore, fine 

/ > ." " . ♦»/ »*' *V ferric oxid be mixed with 

i^V '~,.j'*'\. ' .*V'-' linseed oil it can be easily 

■ ' U ^■'".i-'^'t'f:- ' ^*^" iiom the nature of the 

''^' ..,' , m'"--* .• *^^'' physical characteristics of 

* •^,^*'v;, ^-^ "^ 1 the pigment that a remark- 

. ji'- .^ ■■_.*'• ably good result is obtained. 

< ■', . ,'f Permanent Vermilion 

■^■".'ji'"- It may be of interest 

\... iX. A-ji.cii \\ iii.vATiTi; — i'ii..[<.- to the chemist unacquainted 

tiij. j.-t-m-li yiv. ^-iKoviNj! ;i fciv large- ^^-jth the manufacture of 

'■''""' dry colors to know that 

rji^lish vfrmilinn (sulphide of mercur>'), of which the proto- 

l\|)cs Jirc ChinL'sc vcrmil- 



\iiiiTiiiin quicksilver /^ % V*-'^^***^ 



■riiiMiun, etc., was for- 
M'd whcrev 



f-%.;'.-*^A 



irii-rlv iiM'd wherever a iicr- /"S.^* • i* * '^■■^ N^ 
iiuiji.-jil n-d was desired; /'-l^^Va- '^''/.^.^ ::^ '-'A 
;iij«l piirticularly for mil- jL** "/i'.,.^ j -'41. ,'t''r^ ^*i 
..,;,<l vv..rk was this ver- ^A''V■rf,>'*^i^ '*"''"■ >\, 
i.iilir.n 111.- niily n-<l that ■,;'>'• -V"* '"' /*)^^.^*-> 




if mLTCury is a forced 
■, whidi has the com- 



THE RED PIGMENTS 67 

position just described, is also red, but not very 
bright, and that found and made in Austria, known 
as Trieste vermilion, has always been regarded as the 
most permanent of these sulphide of mercury reds. 
Mixed paint manufacturers do not use it, and in fact 
paint manufacturers generally have discarded it, for the 
reason that the so-called para-nitraniline reds are better, 
cheaper, and more permanent. 

In order that the chemist may understand the com- 
position of the para-vermilions, a complete formula is 
given for their manufacture. 

Reactions involved in Making Para-red 

Part I, (Solution of Para-nitraniline and Diazolizing.) 

NO2 NO2 

C6H4 +2HCI = C6H4 .2HCI 
NH2 NHo 

(para-nitraniline) (para-nitraniline hydrochloride) 

NO2 NO2 

CeH4 .2HCI -h NaNOa = C6H4 -h NaCl -h 2H0O 

NH2 N : NCI 

(benzene nitro-azochloride) 

Part 2, (Beta-naphthol Solution.) 

C10H7OH + NaOH = CioHTONa -h 2H2O 
(beta-naphthol) (sodium beta-naphtholate) 

Part J. (Mixing of No. i and No. 2 to Produce Color.) 

NO2 
C6H4 -h CioHyONa 

N: NCI 
(benzene nitro-azochloride) (sodium beta-naphtholate) 

NO, 
= C6H4 + NaCl 

N: NCioHeOH 

(Para Red) 



68 chemistry and technology of paints 

Para-nitraniline Lake 

Naphthol Solution 

15 grams beta-naphthol or beta-naphthol R.; 30 grams caustic 
soda lye 22° Be.; 10-20 grams para-soap P. N. (In sufficient 
boiling water to dissolve thoroughly). 

Di/vzo Solution 

14 grams para-nitraniline. dissolved in boiling water; 25 grams 
hydrochloric acid 20° Be. ; 200 grams ice. 

WTien the solution is cooled to 32° to 35° F., add very slowly, 
while stirring constantly, 34 grams nitrite of soda solution (29 gms. 
nitrite in 100 gms. cold water). 

Allow to stand 15 to 20 minutes. Then add slowly 35 grams 
acetate of soda previously dissolved in cold water. 

To the naphthol solution add the base you intend to use. 250 
grams of blanc fixe give good results. For bluer shades use beta- 
naphthol R. For yellower shades use beta-naphthol. 

WTien these colors have been precipitated on an 
orange mineral base they have been known to catch fire 
spontaneously in the drying room, and therefore great 
care should be exercised in their manipulation vrfth lead 
bases. 

There appears to be a difference of opinion among 
consumers as to whether these reds are really permanent 
or not. Careful investigation reveals the following: 
The i)ara-vermilions are soluble in linseed oil, and there- 
fore even when a pigment contains only 5 per cent 
tinctorial matter it is useful and effective as a red paint. 
White lead in any form mixed with a para-red destroys 
its color and turns it brown. A few years ago when this 
color first appeared on the market it frequently hap- 
pened that it turned i)erfectly white when exposed to the 
air, but when it was rubbed with raw linseed oil it turned 
a brilliant red again, and a microscopic examination 



THE RED PIGMENTS 69 

showed that the fihn had been entirely incrusted with 
very fine crystals of sodium nitrite and other salts that 
had not been completely washed out of the lake pigment, 
and so para-red obtained a bad reputation, not due to 
the color, but due to the ignorance of the manufacturer. 

Para-red has penetrative powers in both directions; 
when painted, for instance, on a sheet of cloth for sign 
work it will penetrate through and stain the under side 
yellow. If white lead paint be lettered over it, it acts 
the same and turns white lead yellow or a yellowish 
brown. 

Enormous quantities of this vermilion are made every 
year, and so strong is this color that average analyses 
of the paint used for agricultural implement purposes 
wdll show the pigment to be composed of 90 per cent 
barytes, 5 per cent para-red, and 5 per cent zinc oxid or 
zinc sulphide. Its presence in mixed paints is very easily 
detected by boiling with varnish solvents and noting the 
peculiar orange color of the filtrate. 

Helio Fast Red 

This is also known as Harrison Red, and is perhaps 
one of the most permanent pigments that we have of 
the vermilion type. It is made from nitro-paratoluidine, 
and in tinctorial strength is practically ten times stronger 
than a quicksilver vermilion. It dries, however, very 
badly, and when a sufficient percentage of strong drier 
such as a resinate of lead and manganese is added, the 
color tends to darken slightly on exposure. This color 
does not bleed, and it is apparently insoluble in drying 
oil; nor does it turn a white pigment into a brown, as 
is the case with the para-reds. When this pigment is 
mixed or reduced with a large quantity of whiting, 
barytes, or other white base, and exposed to the air it 



70 CHEMISTRY AND TECHNOLOGY OF PAINTS 

apparently fades, and on close examination this fading 
is found to be washing out of the pigment itself and the 
exposure of the base upon which it is made, so that the 
conclusion we must arrive at as regards the permanency 
of this remarkable color is that when used in sufficient 
strength it is permanent, but when diluted, reduced, or 
adulterated to too great an extent the base upon which 
it is made overpowers or masks the permanent pigment 
itself. 

LiTHOL Red 

This is 2 -naphthy lamine- 1 -sulphonic-acid-diazo-be ta 
naphthol, and is sold to color manufacturers in paste 
form as a semi-finished color. 

In the manufacture of permanent vermilion the fol- 
lowing is the method of procedure: 

The paste color is mixed with the desired amount of 
base (blanc fixe, clay, barytes, whiting, etc.) and water 
until a thin, uniform suspension is obtained. Barium 
chloride to the extent of io% of the paste color is then 
added and the whole steamed for about \ hour until 
the shade is fully developed. The color is then washed 
once or twice, pressed, and dried. 

Lithol red has the advantage over para-nitranilines 
in that it does not bleed, and that it does not turn dark 
upon exposure. It is very largely used in the manu- 
facture of permanent railway signal reds, and when not 
reduced or diluted with too much clay and barytes is 
permanent, but when it contains an excess of the so- 
called recnforcing pigments it washes out and fades. 



CHAPTER V 
The Brown Pigments 

The principal brown pigments used in the manu- 
facture of paint, excepting the aniline lakes, are the burnt 
siennas, the burnt umbers, burnt ochres, Prince's Metallic 
or Princess Mineral brown and Vandyke brown. 

The burnt siennas, whether they are American or 
Italian, are a translucent form of ferric oxid and clay. 
In other words, when the hydrated oxid of iron and clay 
mineral are burnt ferric oxid is the result, and the clay 
remains unaltered, any water in combination, of course, 
being driven off. If the resulting color is translucent 
and is of the nature of a stain we call it a sienna, but if 
the resulting color is opaque and of the nature of a paint 
we call it an oxid. 

The umbers are similar in composition to the siennas, 
with the exception that they all contain manganese and 
are of a much deeper brown and do not approach the red. 

The Princess Mineral browTi or Prince's Metallic 
oxids are calcined carbonates, silicates, and oxids only 
found in America, and are very largely used, particularly 
for the painting of wood. 

Vandyke brown is a very deep brown, and is trans- 
lucent when finely ground, containing more than 50 per 
cent of organic matter. 

American Burnt Sienna 

This is a permanent reddish brown pigment made by 
calcining raw sienna, raw sienna being a hydrated oxid 
of iron containing clay. When burnt the percentage of 

71 



72 CHEillSTRV ASD TECBSOLOGV OF PALWTS 

FcjOj, or ferric oxid, ranges from 25 to 60 per cent, 
depending upon the original ore. There is one grade 
found in the Penns\'I\-ania section which assays as high 
as 80 per cent ferric oxid, and is know-n as double strength 
sienna. This is richer and deeper than the Italian sienna, 
and when reduced with ordinary- clay and ground in oil 
makes a staining pigment equal to the Italian. From a 
raw-material standpoint the Italian siennas when tinted 
with 20 iwr cent of white show a bluish tint, whereas the 
. , American siennas show a 

bro^^Tiish or yellowish tint, 
and only one who has had 
a great deal of experience 
in tinting out these siennas 
can tell empirically the dif- 
ference between an Amer- 
ican and a burnt sienna. 
The Italian and the Ameri- 
can siennas normally con- 
tain some calcium salts, 
Amkhiian Hi-KKT Sienna— but occasionally Some ores 
i'i..4iHiii.r..Ktui.h x2;o, csceUeni quai- ^jg found which are free 
i>, mil .imi gruin. j^^^ j.^^ compounds. For 

paint puriK)ses, however, these are no better than these 
lliat lonlain lime, for many grinders add from 5 to 10 
)Mr iiriit (»f whiting to umbers and siennas to prevent 
llii-ni from running or disintegrating when used as stain- 

Italian Bx-rnt Sienna 

(liiliiin Imrnt sienna is made from raw sienna, the 

(iiw sienna ttt-ing a hydrated oxid of iron containing clay, 

III y-liiili I III' iron predominates, the burnt sienna being 

<(| lilt' same composition minus combined water. The 




THE BROWN PIGMENTS 73 

hydrated oxid of iron is normally yellow, and when 
this is burnt the ferric oxid which is produced is red- 
dish or reddish brown. 

Italian burnt sienna differs from most American 
burnt siennas in that its ferric oxid content is generally 
greater. The Italian burnt siennas average from 60 
per cent FcjOs to as high as 75 per cent. The American 
burnt sienna, known as double strength sienna, which is 
equal in iron content to the Italian, differs totally in 
shade, the American being of the order of an Havana 
brown, the Italian being of a maroon type. 

Siennas in mixed paints are largely used for their 
tinting quality, the resulting shade being a yellowish 
maroon or salmon color of extreme permanence. After 
several years' exposure a mixture of white and burnt 
sienna will darken slightly, but will never fade. 

Under the microscope a finely ground sienna shows 
little or no grain. 

Burnt Umber 

Burnt mnber is a very useful pigment, and is found 
in the United States and also imported from Italy, 
Cyprus, and Turkey-in-Europe. All umbers normally 
contain over 5 per cent of manganese dioxid, while 
some of them contain as high as 20^ per cent manganese. 
The Turkey umbers are generally richer in manganese 
than the American umbers. 

A typical analysis of burnt Turkey umber would be 
as follows: 

Calcium Carbonate 7 % 

Silica 34% 

Manganese Dioxid 14 % 



erf 
/o 



Ferric Oxid 42 

Alumina 3 % 

100% 



74 CHEMISTRY AND TECHNOLOGY OF PAINTS 

A typical analysis of an American burnt umber 
would be: 

Silica and Alumina (clay) 60 % 

Ferric Oxid 25 % 

Manganese Dioxid 8 % 

Calcium Carbonate 5% 

Carbon and Carbonaceous matter 2 % 

100% 

These types would indicate that an American umber 
is^ not as strong and does not contain as much ferric oxid 
and manganese dioxid as a Turkey umber. 

BLTusrx Ochre 

Burnt ochre is distinctively an American color, and 
differs in physical quality from burnt sienna in so far as 
the burnt ochre has hiding power and the sienna has trans- 
lucent or staining power. Burnt ochre is more like a brown 
paint, and burnt sienna like a mahogany stain. Burnt 
ochre covers solidly; burnt sienna covers translucently. 

Some of the American siennas which are not good 
enough for staining purposes are burnt and find their 
way to the market as structural steel paints and railroad 
paints of the browTiish red order; as such they are remark- 
ably good in their protective quality against corrosion. 

No standard of composition can be given, as burnt 
ochre varies very much in the percentage of iron, some 
of the burnt ochres ranging as low as 30 per cent iron 
oxid and others as high as 70 per cent, the balance in 
both cases being clay. 

Prince's Metallic or Princess Mineral Brown 

This is one of the best known paints, and has had a 
successful career for more than fifty years. It is a very 




THE BROWN PIGMENTS 

pleasing brown pigment, which has an enormous use all 
over the United States for painting wooden freight cars 
and tor painting tin roofs. Where it is apphed to a flat 
surface like a tin roof it has been used for many years 
in its dr}' state, and mixed with half raw and half boiled 
linseed oil in the field. It is at times fairly fine, and 
while it is an excellent preservative for steel it may be 
regarded as a better preservative coating for wood, as 
many of the wooden bams in the country in the States 
have lasted ten years when coated with two coats of this 
pigment. The analysis of the material varies very much. 

Geologically, the ore is 
a carbonate, and Hes be- 
tween the upper sihirian 
and lower devonian, h {•• 
a massive material of blui^ll 
gray color when mined, [' 
and resembles limestone, v 
although it contains a very \ 
low percentage of lime. 
' The process of mining is 
bj- shaft-work. The ore 
itself lies between two hard 
rocks and rarely ever ex-.'"" "' ''-.','., ,'.*"" '""^ 
I ceeds three feet in width, 

[ and as a consequence the mining is an expensive operation. 
[The ore is hauled to the kilns, where it is roasted, 
I Tv'hich drives off the carbon dioxid and converts it into 
I a sesqui-oxid. The milling is the ordinarj' process used 
y in grinding any of the iron oxids. 

The material was originally manufactured by Robert 
I Prince of New York, who became interested in a slate 
[ quarrj' located in Carbon County, Pennsylvania, from 
twhich locality the original material came. 




. «■ '■^■■ 






;*'^ 



I 




76 CHEMISTRY AND TECHNOLOGY OF PAINTS 

A fair analysis of this material is as follows 

Oxid of Iron (Fej O3) 48.68% 

Silica 33.37% 

Alumina 12.08 % 

Lime 2.02 % 

Magnesia 1.25 % 

Loss on Ignition 2.34 % 

Undetermined 0.26 % 



c 
100.00% 

As the material is not alkaline, the lime and magnesia 
are undoubtedly combined with the silica, so that the 
material other than oxid of iron is silicate of alumina, 
lime, and magnesia. Sometimes, the percentage of Fe203 
will run below 40 and sometimes it will go as high as 50, 
but this really makes no difference in the paint, and in 
view of the fact that it is a natural product and may 
from time to time contain a little gang rock some leeway 
must be given as regards its composition. 

Vandyke Brown 

Vandyke brown is a native earth, and is identical 
with cassel brown. It is popularly supposed that 
Vandyke first used this pigment as a glazing color in 
place of bitumen, and as it is composed of clay, iron oxid, 
decomposed wood, and some bituminous products, it is 
fairly translucent and adapts itself for glazing purposes. 
Because of the bitumen which it contains, it dries very 
badly and very slowly, and has a tendency to crack or 
wrinkle if the under-coat is either too hard or too soft. 
Concerning its permanence, there can be no doubt that 
it darkens considerably on exposure, like all the bitumi- 
nous compounds, and many painters use a permanent 
glaze composed of a mixture of ochre and black tinted 



THE BROWN PIGMENTS 77 

with umber. Where the effect of age is to be simulated, 
there is no objection to its use.^ 

This pigment is used in mixed paints, principally on 
account of its deep shade and translucent appearance. 
It contains upwards of 60 per cent of organic matter. 
A t^-pical analysis would be as follows: 



Organic Matter 65 <^,c 

Ferric Oxid 3 ^e 

Calcium Carbonate 5 ^'l 

Potash and Ammonia Salts 2 



.■V 

Moisture 25 ' c 

* ** Materials for Permanent Painting" by Maximilian Toch. 



CHAPTER VI 

The Yellow Pigments 

^ The yellow pigments are the ochres, the raw siennas, 
chrome yellow, and the chromates. 

The ochres are all rust-stained clay, and both, the 
French and the American contain approximately 20 per 
cent of rust or ferric hydroxid and the balance clay. 

The raw siennas differ from the ochres in that the 
amount of hydrated oxid of iron is often in excess of 
that of clay, and the nature of the pigment is such that 
when finely ground it is a stain and not a paint. 

The chrome yellows are all lead chromate variously 
precipitated and of varjdng composition, depending upon 
the shade. 

The other chromates, such as zinc chromate and 
barium chromate, have come into use in paints within 
the last ten years, owing to their alleged property of 
preventing rusting. 

American Yellow Ochre 

There are large quantities of ochre found in the 
United States, but principally in Pennsylvania and in 
Cieorgia. There are, of course, a great many other 
deposits, but for the paint industry these are the prin- 
cipal sources. American ochre ranges in composition 
from 10 to 30 per cent of ferric hydroxid, the balance in 
either case being clay, and on this point it is well to note 
that ochre and sienna have the same composition, except- 
ing that there is generally a reversal in the percentages 



^o 



THE YELLOW PIGMENTS 



79 



of clay and oxid of iron. Some ochres found in America 
are finer than those imported from France, although 
French ochres as a general rule are decidedly more 
brilliant in color. 

■ In the trade there are many other ochres, which are 
sold under the name of cream ochre, gray ochre, white 
ochre, and golden ochre, all of which are clays containing 
either carbonaceous matter 
or iron rust, for, after all, 
oqhre is simply clay stained 
with rust. 

Cream ochre contains 
as low as 5 per cent of 
iron rust or ferric hydroxid, 
the balance being silica 
and clay. It has very little 
hiding power, and is con- 
sidered of very little value 
as a primer on wood, for 
which it is used to quite 
a large extent. 

Gray ochre is silica, 
clay, and carbonaceous coloring matter, or is colored 
with a trace of ferrous hydroxid or greenish rust. It is 
used as a filler, or for a cheap paint. 

White ochre is nothing more or less than clay, and 
has no value whatever as a paint material. 

Golden ochre is either French ochre or American 
ochre which is brightened ^vith some chrome yellow. 
There are various shades of golden ochre sold, depending 
upon the shade of chrome yellow with which it is mixed. 
Some of them are perfectly orange colored, and contain 
as high as 12 to 15 per cent of chemically pure orange 
.ehrome yellow. 




O. 12. OrDIN'ARV AUERlfAS" W ASHED 

OcElRB — Photomitrograph X250, pow- 
dered and Ixilted; lower in iron than 
the French, but of uniform grain. 




8o CHEMISTRY AND TECHNOLOGY OF FAINTS 

Green ochre is similar in composition to gray ochre, 
excepting that it contains a larger percentage of ferrous 
hydroxid. It is principally found in Bohemia xmder 
the name of terre verte. It has little or no hiding power 
of itself, but is very largely used as a base for cheap 
lakes on account of its 
adsorbent quality for cer- 
tain aniline colors. 

Yellow oxid is a syn- 
onym for raw sienna, and 
is practically the same 
thing. A typical analysis 
of j'cllow oxid will show 
hydrated oxid of iron 70 
■ - -•^w^-krfVM^ P^"^ *^^^^ ^^ clay 30 per 

■^WchtC^ cent. 

No. jj. AuERicAs Waskkd (Xiire— For the benefit of the 

PhotomicroRraph X250, of the same chemist it mUSt be Stated 
comixisitiim as Trenrh <xhre. . , , , 

that when analyses are ■ 
not gi\'en and small percentages of lime and magnesia 
are found, it is understood that these are natural con- 
comitants of ochrey earths. 

French Yellow Ochre 
French yellow ochre has been used in America for 
many years, and is analogous in composition to American 
ochre; but as a general rule the French ochres are more 
brilliant in shade. Nearly all of the French ochres which 
are imported into the United States have a composition 
of about 20 per cent of hydrated oxid of iron and So per 
cent of clay, and one of the most popular brands has 
for \cars been knowTi as J. F. L. S. These letters stand 
for "Jaunc, Fence, Lave, Surfin," which mean, "Yellow, 
Dark, Washed, Superfine." These letters are varied 



TBE YELLOW PIGhfENTS 8i 

according to the treatment that the ochre gets, but the 
J. F. L. S. is the most popular. 

In color, the French ochres are more brilliant, as has 
been stated, but the American ochres are invariably 
finer; but this, of course, refers only to the American 
grades of equal price. 

Chrome Yellow 
Chrome yellow is a lead chromate of medium shade, 
as precipitated from a solution of nitrate of lead and 
potassium bichromate. The 
lemon or lighter shades are 
made from solutions acidi- 
fied with organic or inor- 
ganic acids. An organic 
acid such as citric acid, 
which forms a lead citrate, 
changes the shade, pro- 
•ducing a greenish lemon, 
which may vary from a 
greenish lemon to a bril- 
liant canary, particularly No. 14. j. f. L. s. OcuttE — Photo- 

if sulphuric be added. If micmgraph xjso. showing crystalline 

an alkaline solution of po- 
tassium bichromate be used an orange precipitate is 
produced, so that a great variety of shades of this pigment 
can be obtained. 

All of the chrome yellows are perfectly permanent, 
provided they are thoroughly washed to free them from 
residual salts. Manufacturers are now abandoning the 
old mechanical method of stirring chrome yellow after 
it is precipitated, and are substituting air stirring, which 
avoids any possible tendency to produce lead sulphide, 
the air converting the sulphide into sulphite and sulphate. 




82 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Chrome yellows when thoroughly washed are permanent 
to light, but they cannot be recommended where sulphur 
vapor is generated, owing to the formation of lead sul- 
phide, traces of which detract from the brilliancy of the 
color of the pigment. 

The composition of chrome yellow is as follows: 

Light Chrome Yellow 

PbS04 -h PbCr04 
or, 

2PbC03 • Pb(0H)2-h PbCr04 

or, 
PbCr04 + Citrate 

Tartrate ► of Lead 
or Sulphate ^ 

Medium Chrome Yellow 

PbCr04 

Orange Chrome Yellow 

PbO • PbCr04 = PbjCrOfi 

Chromate of Zinc 

Chromate of zinc has only come into general use 
within the last ten years in mixed paints and paints 
generally, on account of its alleged rust preventing prop- 
erties when used as a priming paint on steel. 

Chromate of zinc is made as follows: Zinc oxid is 
boiled in a solution of potassium bichromate for several 
hours and filtered and dried with sKght washing; or a 
hot neutral solution of zinc sulphate is precipitated with 
potassium chromate. 

Chromate of zinc is soluble to a considerable extent 
in water, and therefore should not be used as a finishing 
coat, as rain will streak the surface. For example, a 
green paint made of chromate of zinc and blue shows 
yellow streaks when exposed to the weather. 



THE YELLOW PIGMENTS S^ 

This material is used to some extent by artistic 
painters, and as oil paintings are never subjected to the 
elements it is under those circumstances a perfectly per- 
manent color. 

For interior painting and flat wall paints, chromate of 
zinc, therefore, has an advantage, as much more brilliant 
tones are obtained and much more delicate shades are 
obtained than with the chromate of lead. It has very 
little hiding power or opacity, and in tinctorial strength 
is much weaker than the chromate of lead. 

If contained in a mixed paint, when the pigment is 
thoroughly washed with benzine and freed from oil or 
medium, chromate of zinc can easily be recognized, be- 
cause the pigment when shaken with hot water in a test 
tube is invariably colored yellow. This, however, must 
be further verified, as barium chromate reacts the same 
way. 



CHAPTER VII 

The Blue Pigments 

The blue pigments usually used in the paint industry 
are artificial ultramarine blue, artificial cobalt blue, and 
Prussian blue. The types of Prussian blue vary very 
greatly \nth their manufacture, and are known imder 
the names of Milori blue. Bronze blue, Chinese blue, 
Antwerp blue, Paris blue, etc. 

Ultramarine and cobalt blues are permanent to light 
and alkali-proof. The Prussian blues are permanent to 
light, but not alkali-proof. 

Ultramareste Blue^ 

Ultramarine blue, whether it is artificial or genuine, is 
chemically the same, with the one difference that the 
genuine ultramarine blue is the powdered mineral known 
as lapis lazuli, and ordinarily is the blue known under 
that name. Furthermore, the mineral itself is foimd at 
times in an impure state either admixed with slate or 
gang rock, or contaminated slightly with other minerals, 
and the genuine ultramarine blue may run, therefore, 
from a very deep blue to a very pale ashen blue; in fact, 
the lapis lazuli which lies adjacent to the gang rock is 
ground up and sold under the name of ultramarine 
ashes, which is nothing more nor less than a very weak 
variety of genuine ultramarine blue. 

PYom the standpoint of exposure to light or dr>dng 
quality, the artificial ultramarine blue is just as good 

1 ''Materials for Permanent Painting/' by Maximilian Toch. 

84 



THE BLUE PIGMENTS 85 

as the genuine, and the only advantage that the genuine 
has over the artificial is that the genuine is not so quickly 
affected by acids as the artificial is. 

It may be of interest to know that in 1814 Tessaert 
observed the accidental fcj,'**ic'«*j 

production in a soda oven 
at St. Gobain (France) of /^^.^ ^i^^^'^ 










made by Huhlmann (at 

St. Gobain in a sulphate 

o\'en) and by Hermann 

in the soda works at No. 25. Ultrvmahike Bmk — photo- 

Schoenebeck (Prussia). microgm,.h xjoo. 

In 1824 La Soci^t^ d 'Encouragement pour Industrie 

offered a prize of 6000 francs for the production of artificial 
ultramarine blue, which, 
in 1828, was awarded to 
J. B. Guinet, a pharmacist 
of Toulouse, later of Lyons, 
who asserted that he first 
produced ultramarine in 
1826. Vanquelin was one 
of the three " trustees," 
holding the secret contrary 
to the rule of the Soci^t^. 
In -December, 1828, 
Gmelin of Goettingen ex- 
plained his process of mak- 
ing artificial ultramarine 

before the Acadamie des Sciences of Paris. He used as 




No. 16. Ultkauarine Blue, ground in 
oil, very uniform and fine — Photo- 
micrograph XI 50. 



86 CHEMISTRY AND TECHNOLOGY OF PAINTS 

the basis a mixture of precipitated hydrate of alumina 
and silex, which was later on superseded by China day 
(kaolin). 

In 1829 Koettig produced ultramarine at the Royal 
Saxon porcelain factory at Meissen. 

In 1834 Leverkus, at Wermelskirchen, and later at 
Leverkusen, on the Rhine, produced the pigment. 

In 1837 Leykauf & Zeltner, at Nueremberg, introduced 
the manufacture of ultramarine into Germany. 

Prices of ultramarine in 1830: 

Natural $50.25 per pound 

Artificial 4,05 per pound 

Ultramarine is composed of alumina, silica, soda, and 
sulphur, as follows: 

Ultramarine (pure blue) containing a miTiiTniiTn of 
silica seems to be a more or less well-defined chemical 
body, i.e., a double silicate of sodium and alimunium 
with sulphur as a poly-sulphide of sodium, or as a thio- 
sulphate. 

Ultramarines Poor Rich 

in Silica in Silica 

Alumina 29,00 23.70 

Silica 38.50 40.80 

Soda 22.50 19.30 

Sulphur 8.20 13.60 

Undecomposed 1.80 2.60 

100.00 100.00 

R. Hoffman gives the following proportions: 

Alumina Silica 

Poor in silica 100 128 

Rich in silica 100 170 



THE BLUE PIGMENTS 87 

In resistance to alum the different products rank as 
follows : 

Lapis Lazuli First 

Artif . Ultramarine (rich in silica) .... Second 
Artif . Ultramarine (poor in silica) . . . Third 

In 1859 Leykauf discovered the purple and red varie- 
ties of ultramarine, which were produced by the action 
of hydrochloric and nitric acids, and by heating ultra- 
marine with calcium chloride, magnesium chloride, and 
various other chemicals. In this way there were pro- 
duced a variety of shades, and by the addition of such 
substances as silver, selenium, and tellurium, even yellow, 
brown, purple, and green shades were produced. 

All of these colored ultramarines are exceedingly 
permanent to light, but have little or no hiding power, 
and when used alone are perfectly permanent. 

The ultramarine blue which is made by means of a 
potash salt instead of a soda salt has every analogy of 
color and shade to genuine cobalt blue, excepting that 
the genuine cobalt blue is not affected by acids as 
rapidly as the artificial. 

Artificial Cobalt Elite 

The cobalt blue of commerce is the same as ultra- 
marine blue, the difference being in the shade. Ultra- 
marine, when mixed with thirty parts of a white pigment, 
such as zinc oxid, produces a violet shade, whereas the 
cobalt blues when mixed in the same proportion produce 
a turquoise or sky-blue shade. Chemically, the com- 
position of these ultramarines and cobalts will average 
about 50 per cent silica, 22 per cent alumina, 15 per cent 
sodium sulphide, in combination wath 3 per cent water 
and 10 per cent sulphur. The addition of the slightest 



88 CHEMISTRY AND TECHNOLOGY OP PAINTS 

trace of acid to a paint containing ultramarine blue 
liberates HiS, which always indicates the presence of 
ultramarine in a blue or , bluish pigment. Under the 
microscope ultramarine ,blue has a distinct crystal- 
line appearance. When these crystals are badly de- 
stroyed bj' fine grinding the color suffers very much, the 
characteristic brilliant blue of ultramarine becoming an 
exceedingly muddy shade. Its tinctorial power is very 
weak, but it is exceptionally permanent to light, ii 
.-■f'i..-. blue shades of mixed paints 

■r^-iT- ^. J|j3^k ^^^ percentage of ultra- 

^ -\^"|"f' *^-*^7^?^bik marine blue can be deter- 
^^^'' t!^^- -^ ■i-Jc'^^M. mined either by difference 
^■r-^' X--"''- •^- ?'«'^^^3P ^^ ^^ ^^^ percentage of 
.•■C-».V"*^^^^''*i'\S2 sulphur present. If lo 
^^ti'-'^^^^'.^.Ji^'j^jl per cent is accepted as 
Vf^.'Ji ,. Y'L\'^<Ijm the amount of sulphur in 
C'*'^V'" *■'"■((.'::. ./-^jJO^F ultramarine blue, a fairly 
^ .. ■.' >'*^.^:c.«^ accurate quantitative de- 
termination can be arrived 
No. 27. ARTinciAL Cobalt Bute (same at. Where ultramarine blue 
as uii;^- Wwc) — Phoiomicrograph jg mixed with lithoponc the 

X2$o, crystalline grain. . 1 1 -j t ^.i i*.i 

zmc sulphide oi the Iitho- 
pone as well as the ultramarine evolve HjS, When deter- 
mining the ultramarine, the total HiS evolved must be 
calculated as sulphur. The zinc must be precipitated as 

carbonate and weighed as oxid and calculated to sulphide. 
The sulphur in the ZnS must then be deducted from 
the total sulphur. From the difference the percentage 
of ultramarine blue in the original pigment may be cal- 
culated. As acetic acid liberates the H^S from the 
ultramarine but docs not attack the S in lithopone, this 
add may be used and the percentage of sulphur in the 
ultramarine determined directly. 



THE BLUE PIGMENTS 89 

Ultramarine blue reacts wdth corroded white lead 
but not with zinc oxid. It does not react very quickly 
with sublimed lead or zinc lead, but for the making of 
pale blue shades, which should remain permanent in the 
package, zinc oxid is to be recommended in preference 
to any other white pigment. Ultramarine blue should 
not be mixed with any of the chrome yellows or chrome 
greens, because a darkening effect is sure to take place. 
Ultramarine blue behaves very badly with linseed oil 
containing an excessive amount of lead drier. For mixed 
paints of pale tints a resinate of manganese or oleate of 
manganese drier is to be recommended. Most of the 
Japan driers contain large quantities of lead, and a white 
Japan composed of rosin, manganese and linseed oil wall 
make the most permanent mixture. 

Prussian Blue 

Synonym : Milori Blue, Bronze Blue, Antwerp Blue, Chinese Blue, 

Paris Blue, etc. 

Almost every text-book on elementary chemistry 
gives a description of Prussian blue, which is a ferri-ferro- / 
c>'anide of iron, and in a general way it can be produced 
for laboratory purposes by the simple mixture of ferro- 
cyanide of potassium and a ferric salt of iron. Com- 
mercially, the well-known ferric iron reaction of analytical 
chemistry is reproduced on a large scale. Prussian blue, 
however, is made from a ferrous salt and is obtained by 
the mixture of ferrous sulphate (copperas) and ferro- 
cyanide of soda or potash (yellow prussiate). This mixture 
produces a pale bluish white flocculent precipitate, and the 
chemist will easily understand how, with the addition of 
any oxidizing agent, such as bleaching powder, potassium 
chlorate, etc., the precipitate is converted from a bluish 
white into a dark-blue pigment. 



90 CHEMISTRY AND TECHNOLOGY OF PAINTS 

There are a number of varieties of Prussian blue, all 
approximating this composition but made differently, 
being sold under the names of Steel blue, Milori blue, 
Bronze blue, Antwerp blue, Chinese blue, and Paris blue. 
Although each of these blues is chemically the same as 
Prussian blue, they have different physical character- 
istics. Prussian blue, for instance, is like a mixture of 
indigo and black in its dry state, and when tinted with 
one himdred times its own weight of zinc oxid the shade 
produced is a muddy violet. Chinese blue, when treated 
in the same manner, gives a purer blue which has no 
trace of violet in the shade. The Steel blue, when diluted 
one hundred times, gives a turquoise shade. And so for 
the manufacturer of pale blue shades the tones of these 
blues must be taken into consideration. 

There is much discussion among paint manufacturers 
as to whether Prussian blue is a permanent pigment or 
not, and the author is frank to say that this matter can 
be decided as follows : Prussian blue, or any of its varieties 
may be considered permanent or fugitive, according to the 
manner in which it is made and according to the base 
with which it is mixed. If Prussian blue contains more 
than a trace of soluble salt (sodium sulphate), it has a 
decidedly yellowing action on the oil, and a light blue 
or light green made of such Prussian blue is supposed to 
be fugitive. On the other hand, a number of experi- 
ments made with thoroughly washed Prussian blue have 
demonstrated that it is a perfectly stable color and does 
not change its shade. As a tinting color for making pale 
blues in mixed paints Prussian blue has caused an enor- 
mous amount of trouble. A pale blue mixed paint that 
contains white lead in any proportion changes color in 
the package, a reduction process taking place which 
converts it from a ferric into a ferrous state, so that 



THE BLUE PIGMENTS 91 

when a can of light blue mixed paint made with Prussian 
blue and white lead is opened it is a sickly green instead 
of a blue. If such a paint be applied to an exterior 
surface it is completely converted into its original blue 
shade as soon as it is dry. The zinc oxid paints have the 
same action, but to a very small degree, and a paint 
manufacturer who desires to make a pale. blue by the use 
of Prussian or Chinese blue must avoid the use of white 
lead in his paint. The artificial cobalt blue mixed with 
zinc oxid is, however, more desirable. 

Prussian blue is also used in srriall quantities for mix- 
ing with bone black to produce intensely black shades. 

It is a simple matter to determine the presence of 
Prussian blue in any pigment by the addition of caustic 
soda to the dry extracted pigment, warming, filtering, 
and testing the filtrate with a drop of ferric chloride after 
acidifying. The Prussian blue made in laboratories 
will contain approximately 30 per cent of iron, so that if 
an analysis is made of a mixed paint tinted with Prussian 
blue and the percentage of iron is multiplied by three, a 
fairly correct estimate of the percentage of Prussian blue 
is obtained; and while the factor given cannot be abso- 
lutely correct, owing to the difference in the various 
blues made, it is so nearly correct that a synthesis made 
from such an analysis has invariably given the same 
shade. 



CHAPTER VIII 

The Green Pigments 

The greens used in the manufacture of paints are 
the so-called chrome greens, which are mixtures of chrome 
yellow and Prussian blue, the genuine chrome greens or 
chromium oxid, the aniline lakes, zinc green, and the 
verte antique or copper green. 

Chrome Green 

Chrome green is sold under various proprietary names, 
and must not be confounded with the oxid of chromium. 
Chrome green is essentially a mixture of Prussian blue 
with chrome yellow, but the chrome greens, imless chemi- 
cally pure, are always mixtures of blue and yellow on a 
barytes or mixed base. 

A green paint made entirely of Prussian blue, .chrome 
yellow, and an inert base, such as silica or barytes, is 
very easily analyzed by ignoring the pigment and weigh- 
ing the base, calculating the pigment by difference. This 
is, however, not a desirable method to reconunend except 
in the hands of an expert who knows that the pigment or 
])iiint is made on an inert base. Inasmuch as there is a 
great \'aricty of shades of chrome green, ranging from a 
yellowish green to a vcr}^ dark olive, and as the dark 
slKides may he composed of either a mixture of orange, 
elirome yellow, and Prussian blue, or a Ught chrome 
yellow and Prussian blue and black, it is not safe to 
nuillii)ly the percentage of iron by a factor to obtain the 
l)er(entage of Prussian blue, because many shades of 



THE GREEN PIGMENTS 93 

green are produced with the use of ochre. The iron 
factor would therefore be misleading. The lead chro- 
mate can be washed out with hot hydrochloric acid and 
will precipitate on cooling. The Prussian blue may be 
washed out writh a caustjc alkali solution, the iron being 
left behind, but it can be reprecipitated as Prussian blue 
with a ferric salt, the necessary amount of chrome yellow 
and Prussian blue originally used being thus recovered. 
This method is uncertain only when an olive-yellow is 
being analyzed. 

Chrome green should never be mLxcd with white lead 
for the pale shades, as it changes color in the can in 
proportion to its content of Prussian blue. Zinc lead, 
zinc oxid, sublimed lead, or lithopone should therefore 
be used. If chrome green is not well washed the soluble 
salts are likely to affect the linseed oil. At the seashore 
the salt atmosphere invariably attacks chrome green and 
bleaches it, and where an absolutely permanent green is 
required chromium oxid should be used. 

Chrgmiitii Oxid 

Chemical Formula : Cr203 

This green is one of the oldest greens in existence, 
having been used for very many years, but never having 
been used for mixed paints or by the paint manufacturer, 
excepting for artists' use, until within the past six years. 
WTiile it is expensive compared to the chrome green as 
prexiously described, and while it is weaker in tinting 
p>ower and lacks in brilliancy, it nevertheless is the only 
perfectly permanent green made. It mixes with every 
other pigment without decomposition and stands the 
light without fading or darkening. No alkali discolors 
it, and therefore in the modem flat wall paints where 
delicate greens are desired chromium oxid has come to 



04 CBEJiiSTRY AND TECHNOLOGY OF PAINTS 

pby 4L \x^n* significant role. Many manufacturers get 
KXK^ tW their fancy colors, such as greens, blues, and ver- 
m3iv>tt:s iind any man who makes a perfectly alkali-proof 
xi;j^tl jxAint is entitled to a higher price if the goods are 
IvUcr than those of his competitor. 

i^hr\>mium oxid frequently possesses coarse qualities. 
It 15^ made as follows i^ 

Kight i>iirts potassium dichromate and 3 parts of pure 
tKuie iiciil are ground with water to a stiff paste. The 
uuxlviu* is then heated to dull redness for about 4 hours 
\\\ u rexerberatory furnace. The melt is thrown into 
wuler and boiled, to decompose borates of chromium and 
lK>lassium into boric acid and chromium oxid (hydrated). 
V\w latter is then washed, dried, and ground. 

After it comes out of the dry room it has to be ground 
in a burr stone mill with water exactly like an oil color. 
This develops whatever brilliancy there is in the color 
and increases its hiding power, but unfortunately it also 
develops a ** float'' of a very much more brilliant green 
than the natural chromium oxid. This float is similar 
\\\ color to the well-known Veronese green or hydrated 
oxid of chromium, but is not apparent in the quicker 
drying types of paints. 

Chromium oxid is now largely used as a basic color 
\\\ automobile painting, particularly in the painting of 
llu' hoods, and also for the manufacture of the best 
Ispr of chirk green engine enamels, because excessive 
luuilinKi ^^^ alternate heating and cooling, does not affect 
i( ill rtluide as it does the chrome green made from yellow 
•mmI hiiir. 

riuii' is every reason to believe that this pigment 
^vlll hi' um'tl in greater quantities than it has been because 
(i| ih) hUMling (|ualities. 

* Chem. Ztg. 9, 851. 



the green figments 95 

Green Aniline Lakes 

Flat wall paints, which are very largely used in 
America, are the cause of the manufacture of certain 
green aniline lakes which are not permanent to strong 
light but are permanent to alkali, and are therefore used 
to some extent for making very brilliant green house 
paints for interior decoration. 

These lakes can be readily tested by mixing them 
with soapy water and lime, and if they remain un- 
changed for five minutes they may be regarded as 
permanent, because the majority of the aniline lakes 
which are not alkali-proof are immediately converted 
into a yellow or yellowish brown color when mixed 
wath this reagent. 

The aniline lakes have no hiding power, but have 
tinting strength, and are only used as tints. For making 
ver>^ brilliant greens that have hiding power the chromium 
oxid is used as a base and the aniline colors to obtain 
brilliancy. 

Zinc Green 

Zinc greens are generally mixtures of chromate of zinc 
and Prussian blue, and are extremely brilliant, perma- 
nent to light, but not permanent to alkali or to water, 
as the chromate of zinc remains slightly soluble imder 
many conditions. 

This particular type of green is also largely used for 
interior decorative purposes and for the manufacture of 
flat wall paints. It is much more expensive than the 
chromate of lead green. It is also used to some extent 
as a coach color. Where it is varnished over this color 
is not soluble. 



96 chemistry and technology of paints 

Verte Antique (Copper Green) 

The pigment for making verte antique or antique 
green for copper imitation is generally the bicarbonate of 
copper. It has little or no hiding power, but the corroded 
copper effect cannot be very well imitated with any other 
pigment. It is manufactured as follows: 

A solution of blue vitriol is precipitated with sodium 
carbonate, yielding a basic copper carbonate, carbon 
dioxid being evolved in the course of the reaction. 

2CUSO4 -f 2Na2C03 + H2O = CuCOa- Cu(0H)2 -f 2Na2S04 + COj 

There are a number of other methods in use for 
making copper green which are more lengthy and trouble- 
some to carry out. 

The lack of hiding power of this color is one of its 
good qualities, because the under coat usually is a copper 
color, made by so mixing a para toner and Princess Metal- 
lic brown that the translucency of the bicarbonate of 
copper gives the effect of actually corroded copper. 
Frequently this color is stippled on, and sometimes it it 
flowed on. Where opacity or hiding power is wanted 
chromium oxid and bicarbonate of copper are mixed. 
This pigment is permanent to light, and is at present 
practically the only pigment made or used which con- 
tains copper. 



CHAPTER IX 

The Black Pigments 

The principal dry pigments used in making black 
paint are as follows: 

Lampblack Vine Black Black Toner 

Carbon Black Coal Benzol Black 

Graphite Ivory Black Acetylene Black 

Charcoal Drop Black Mineral Black 

There are quite a large variety of bone blacks, begin- 
ning vdih ivory black and going down to the by-product 
of the sugar mills known as "Sugar House black." In 
composition all of the animal blacks are alike, in so far 
as they always contain carbon and calcium phosphate. 
The carbon varies between 15 and 23 per cent, the 
rest being phosphate of hme and moisture. Some of 
the best blacks used for mixed paints are made from 
the shin-bone and skull of. the sheep, it ha\dng been 
found that these blacks are of the most intense color. 
Occasionally variable amounts of calcium carbonate are 
found in these blacks, depending largely upon the length 
of time the bone was burned. For making a verj'^ intense 
and good quality black which w^ill not settle when mixed 
with varnish, carefully selected bones or burnt ivory 
chips are taken, and digested in hydrochloric acid, w^hich 
removes all the lime salts and leaves the carbon as a 
flocculent residue. This carbon is probably the highest 
priced and most intense black used by paint makers, 

97 



98 CHEMISTRY AND TECHNOLOGY OF PAINTS 

and is frequently sold under the name of black toner, 
because it sometimes is used for giving an intense tone 
to an otherwise pure black. In the material known as 
Black Color in Varnish, it is found that black tone 
serves its purpose best, and a black paint which is con- 
posed of black toner groimd in linseed oil and redticed 
with a very high grade of coach varnish is worth from 
$4 to $6 per gallon. 



Lampblack 

Lampblack is the condensed smoke of a carbonaceous 
flame, and at present is made from a hydrocarbon oil 
of the type of dead oil, or it may be made from a number 
of distillates which on burning give a condensed black 
soot. Lampblack is still made from resinous woods, 
tar and pitch where the dead oil is not obtainable, and 
while many people are inclined to regard lampblack and 
carbon black as the same, they are not by any means the 
same from the paint manufacturer's standpoint, for lamp- 
black is distinctly gray when compared with ivory black, 
bone black, or carbon black, and as a general rule lamp- 
black makes a bluish gray when tinted out with white, 
one hundred parts to one, whereas bone black and ivory 
black as a rule make a brownish tint. This is an empiri- 
cal method for differentiating them. 

The specific gravity of lampblack is generally less than 
two, and one pound of a very pure lampblack without 
undue pressure will fill a package which is over 200 
cubic inches in size, and very often over 230 cubic 
inches or one American gallon. 

Lampblack is distinctly an American product, as is 
e\adenced by the enormous amount of blacks of this t3Tpe 
which are exported; a careful search of the imports fails 



THE BLACK PIGMENTS 99 

to show any appreciable amount which comes into this 
country.' 

Lampblack as it is made now is exceptionally pure, 
and contains more than 99 per cent of carbon. Occasion- 
ally, however, samples are found which contain a small 
percentage of unbumed or condensed oil, which will 
retard the drying of lampblack to such an extent as to 
make it at times unfit for use. Prior to 1906 there were 
many cases where lampblack contained unsaponifiable 
grease, and the author de- 
vised a method for remov- 
ing this with 62° naphtha, 
changing the slow drying 
lampblack into one which , 
dried definitely; but since 1 
that time, due to improve- ' 
ments in the selection of 
lampblack and the greater 
care taken in its manu- 
facture, it is very difficult 
to find a lampblack which 
contains less than 99.5 per ^°- '^ L«a.«"CK-rhotomicn>gmph 

'^ -J t^ X300, very uniform, 

cent carbon and which 

does not dry within a reasonable time. It must be taken 
into account that lampblack is always a slow drier. 
Whether this is due to the fact that it prevents the blue 
rays of light from entering the oil, or whether it is an 
inherent paralysis, has not been definitely decided, but one 
thing is positive, that where lampblack contains unbumed 
or condensed oil the drying is in a large measure paralyzed. 

' A most escellent historical treatise on lamp and carbon blacks 
will be found in the original communications of the Eighth Inter- 
national Congress of Applied Chemistry, Volume 12, page 13, by 
Godfrey L. Cabcrt. 




^«a55.^ 



CHEMISTRY AND TECHNOLOGY OF PAINTS 




Carbon Black 

Carbon black is in ail respects similar to lampblack, 
except that it is intensely black in color, and while it 
shows no crystalline structure under the microscope it 
condenses itself so hard on the places from which it is 
scraped that it is largely interspersed with flakes of black 
which to all appearance are crystalline and are verj- 
refractory in the mill. Its tinctorial power is very great, 
one pound being sufficient 
to tint one hundred pounds 
of white lead to a dark 
gray. Paint manufacturers 
have, however, abandoned 
[ its use as a tinctorial ma- 
terial for several reasons, 
the principal ones being 
that it is likely to produce 
a streaky color when used 
as a tint, owing to the pres- 
ence of very small nodules 
that do not show up untU 
it is applied as a paint 
(and these streaks cannot be brushed out). In the 
second place it shows a peculiar tendency to attach 
itself to minute air bubbles, so that when made into a 
mixed paint of a lighter tint and allowed to stand in the 
package for a considerable time, fairly large amounts of 
black rise to the top of the liquid. Only with the great- 
est difficulty can these be remixed mth the rest of the 
pigment to produce a uniform tint. 



No. ag. Carbon Black — Photomicro- 
graph xjoo, very uniform. 



THE BLACK PICMEXTS 



Graphite 

Synonym : Black Lead, Stove Polish. Specific Gra\-ity : 1.19 to 2.5, 
depending upon the impurities contained in it ■ 

Graphite is found as a mineral almost all over the 
world. It is ver>' largely used as a paint pigment, and 
it is remarkable that in its natural state it has all the 
defects of bulkiness which red lead has for weight. The 
purer a paint jiigment is as to its content of carbon the 
piKircr is the paint pro- 
duced. If graphite be taken 
with a content of 80 or 90 
per cent carbon and mixed 
with linseed oil, it forms a ii 
porous, flufly film, and the 




). jo. Xatlrai. Gh,\pjiiie — I'holo- 
inicrograph X150, containing about 
40 per cent of silica, showing crystals 
of silica and graphite. 



particles of graphite coagu- 
late in the linseed oil and 
produce a very unsatisfac- 
torj- covering. If graphite 
be diluted with a heavier 
base its weakness then be- 
comes its strength and a 
verj- good paint is formed. 
Many of the characteristic 
chemical and physical defects of red lead are largely 
reduced and frequently eliminated when it is mixed in 
proper proportion with graphite, a high grade of graphite 
when finely ground with linseed oil acting as a lubricant 
and sliding under the brush. 

Pure graphite, as is well known, will co\-er from 1000 
to 1600 square feet to the gallon. Such a paint film is 
so exceedingly thin that, while it looks good to the eye, 
in a short period decomposition more easily takes place 
beneath it than beneath many poorer paints. It is there- 




I02 CHEMISTRY AND TECHNOLOGY OF PAINTS 

fore essential to reduce graphite with a hea\aer base, and 
to this end it has been found that a mixture of silica 
and graphite produces very good results; but even this 
paint has the objection of ha\Tng too much spreading 
power. 

^lisnomers have crept into the paint trade in regard 
to graphite paints, such names as green graphite, red 
graphite, browTi graphite, etc., being in use, when in 
reality such graphites do not exist, excepting as far as 
graphite has been mixed with pigments of these colors. 

A six-year test of a 

linseed oil paint made with 

^ ^^^ ^ ' %m\^ ^ neutral ferric oxid, con- 

M j^ ^ it g'^. taining in its composition 

^ *W S ^5 P^^ ^^^^ ferric oxid and 

w • «^ \^ <iii» tgr ^^ P^^ ^^^^ silica mixed 

JC. • «y ^ ■ with graphite containing 85 

■ffigf^ ^^4^ ' * '*•' P^r cent graphitic carbon, 

gi^ 3a%J^ ^^ ^^^ proved itself to be as 

V* ^V good a paint as can be 

^^|N^ ,P^ desired for ordinary'- pur- 

poses. The pigment in a 

No. 31. Natural Graphite — 90 per . . . i • j -ii 

ccnl carbon, very finely i)o\vdcre<l. pamt Ot thlS kmd Will 

withstand the chemical ac- 
tion of gases and fumes, but the oil vehicle is its weakest 
part. 

Since the electro-chemical industry has been developed 
at Niagara Falls graphite has been made artificially and 
is sold under the name of *^\cheson Graphite." This 
graphite is to be commended as a paint material on 
account of its uniformity and fineness of grain, but it 
should not be used alone as a pigment, for as such it 
possesses the physical defect of lightness just described. 
A graphite paint containing more than 60 per cent graph- 



s. 



THE BLACK PIGMENTS 103 

ite does not serve its purpose very well unless 40 per 
cent of heavy pigment is added, such as a lead or a zinc 
compound. A rather unfortunate defect in the graphite 
paints containing a large amount of graphite is the 
smooth and satin-like condition of the paint film, which 
is poorly adapted for repainting. It has often been 
noted that a good slow-drying Imseed oil paint will curl 
up when applied over certain graphite paints, because 
it does not adhere to the graphite film. On the other 
hand, if particular forms of 
calcium carbonate, silica, 
or ferric oxid are added 
to graphite a surface is 
presented which has a 
"tooth," to which succeed- 
ing films adhere very well. 
The question of the co- 
efficient of expansion in 
paints has not been thor- 
oughly considered, and 
many a good paint will No. 32. ARnnciAL Graphite (Acheson) 
fail because it is too elastic. -" Photomicrograph XJjo, conuin- 
, . ing go per cent uf carbon. 

Engineers sometmies pre- 
fer a paint which when scraped with a knife blade 
will curl up like ribbon. Priming coats suffer very 
much when they are as elastic as this, but the paint 
chemist can overcome these defects by the proper ad- 
mixture of inert fillers and hard drying oils. 

Graphite is known as a very slow drier, but this is 
true only when too much graphite is used in the paint. 
There is no reason why a graphite paint should not be 
made to dry sufficiently hard for repainting within 
twenty-four hours. 




CHEMISTRY AND TECHNOLOGY OF PAINTS 



It is not generally known that charcoal from the 
willow, maple, and bass trees is largely used as a pigment 
for black paints. There are a number of black paints 
on the market which are composed of charcoal, lampblack, 
litharge, and linseed oil in varjing proportions, and in 
the early history of these paints it was difficult to make 
them so thin that they would not turn semi-solid in the 
.Mu «^ package. It was found that 

«i*i^Ait^'-* f^ as a preservative coating 

•\^^ *T ,-,*'>* on steel they did remark- 

jf^SC^'^i^t^ ^^'^' ^^■^'*' Investigations 
^^^^^3^^eiS ^^ ^^^ author have shown 
** Sj^ %i^*'3^ jiXf"^ ^^^^ ''^'^ preservative ac- 
^ ( »1?-J*V**>S' •'5*i' tion is incidental and is 
f due entirely to the alkali 
contained in the charcoal. 
Some of the charcoal used 
'■'O uJC*>^" "^ ^^ ^ b\-prcduct from paper 

No. 33- Artifici.u. tiH,\Pi!iTE (Ache- mills and contains as high 
son) — Photomicrograph xis°, "»'- as 2 per cent of potassium 
carbonate. In fact, the 
carbonate is produced by the burning or calcining of wood, 
most charcoal being more or less alkaline. In the exami- 
nation of paints of this character it was noticed that the 
spectroscope showed the potash lines, and thus it became a 
very simple matter to determine by means of the spectro- 
scope whether a paint was a charcoal paint or not. The 
author has demonstrated on pre\'ious occasions that the 
oxidation of metal cannot take place in the presence of 
certain alkalies, and therefore these charcoal paints when 
freshl)' made are excellent preservati\'es for the metal. But, 
inasmuch as moisture is always present in these paints, 






THE BLACK PIGMENTS 103 

ha\Tng been added in the form of water or contained in 
the raw materials, saponification takes place more or less 
rapidly, so that the paints 
are sometimes unfit for 
use two months after they 
are made. 

The charcoal above re- 
ferred to, which is the 
b>-product from the paper 
mills, while not so suitable 

for the manufacture of " j . j^ 

mixed paints, has, however, ■ ^ ' ^. ' ■ V 

been verj- largely used in ^ v 

the manufacture of oilcloth -. . ~ '^p, 

and coated leather. graiili x6oo. 

VixE Black 
In all essentials this pigment is the same as the pow- 
dered charcoals for paint 
purposes, excepting that 
A^ , the grain is smaller and the 

tij^ J| ► black denser. It is made 

^v • ^ *" , • \ in German}' bj- charring 

- ^fe - ^^^^j^iTl the grajjeNine. If o\er- 



m 



j charred it is likely to 

become too alkaline. The 

same tests may be applied 

to this black which were 

--^^ ^ .*'.^ -'"^' used for all the charcoal 

No. 35- Charcoal Black - Phoiomi- and WOod pulp blacks, the 

crograph x6oo, showing hexagonal simplest and most effec- 

stmcturc ol the wood. ^j^.^ j^g^ ^^^^ ^^ j^^jj ^^^ 

black in water, filter, and add a few drops of phenol- 
phthalein. 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



Coal 

Powdered anthracite and bituminous coal are likewise 
used in black paints, but the origin of their use is due to 
some extent to poorly written paint specifications. An 
engineer will at times prescribe a paint containing a cer- 
tain percentage of ash, and in order to meet this require- 
ment a paint manufacturer will have to add coal in order 
to conform with the requirements, but as sulphur com- 
pounds such as SOj and S0» 
always exist in coal a paint 
is produced which is ex- 
ceedingly harmful to metal. 

Ivory Black 
Ivory black is still used 
to some extent for very 
intense coach colors, and 
there is also a very fine 
species of carbon black on 
■ the market known as the 
"Extract of Ivory Black," 
which is made by digesting 
charred ivory chips in hydrochloric acid until nearly all 
of the calcium phosphate is dissolved. Such a black has 
intense staining power, and is b}- far the blackest material 
made. It is very expensi\'e, colloidal in its nature, and 
used therefore for ready prepared color-in-varmsh or high 
grade black enamels. 







^ 




No. 36. \1NE IfLACK ( 


(icrman make) - 


Photomicrograph x. 
Rrain. 


2SO, two sizes 1 



Drop Black 

Drop black is generally made by calcining sheep bones, 
which are then impalpably ground in water, and when in 



THE BLACK PIGMENTS 107 

paste form cast into small drops; hence its name, "Drop 
Black." These cone-shaped drops were largely used 
twenty-five years ago, and then were an indication of a 
good black, but at present the name "Drop Black" 
still clings to finely powdered bone black. So-called 
drop black is generally composed of from lo to 20 per 
cent of carbon and from 80 to 90 per cent of cal- 
cium phosphate, and is sold entirely for its intensity of 
blackness. 






Black Toner 

Black toners may be either the extract of ivory 
black, the extract of bone black, or certain forms of 
carbon black, or carbon 
black upon which nigro- 
sine has been precipitated. 
Another method for mak- 
ing black toner is to 
precipitate red, yellow, and 
blue aniline upon the ex- 
tract of ivory black, which 
produces an intensely 
black pigment that is 
flocculent and remains 
in suspension a long time. 
The principal difficulties 
with these coal tar blacks, ^™"'' 

however, are : first, they are not really black in the 
sunlight; and second, they paralyze the drjing quality 
of any varnish with which they may be mixed. There 
are a number of specially fine blacks that can be used for 
black toners, such as condensed carbon from benzol or 
acetylene. Benzol black is remarkably fine and intensely 




No. 37. WiM)D Pule 
micrograph X500, 



II LACK — J'hoto- 
k-ery tine uniform 



lo8 



CHEMISTRY AND TECBNOWGY OF PAINTS 




5->v 






^ 






black, and inasmuch as there may be an overproduction 
of benzol in the United States within the next few 
years it is very likely that benzol black will become a 
reasonable article of commerce. 

Benzol Black 

Benzol black is a carbon 
black which, however, is 
much better than the car- 
bon black produced from 
natural gas. It is soft, 
contains no granular par- 
ticles, and remains in sus- 
pension for many weeks 
in both oil and varnish. 
It is, however, a very poor 
drier, like most of these 
blacks, and therefore a 

mixture of litharge and red lead oil is recommended 

when they are to be used. 



Acetylene Bl.\ck 

This black is not quite 
as common as it was some 
years ago. It has very 
desirable properties and 
can be used for tinting 
])ur])oscs without showing 
granules or streaks, as is 
often the case with car- 
bon black made from 
gas. It is flocculent and somewhat colloidal in 



No. jS. Dh(.p 
graph X300. Ti' 




i — Photomkro- 
;ly powdered. 



the black pigments 109 

Mineral Black 

Mineral black is usually composed of hea\'y black 
slate, more or less finely ground, and as a paint pigment is 
inert. It is often toned with lighter (in specific gravity) 
carbons and lampblacks, but is not largely used on 
account of its destructive action on paint mills. Where 
iron paint mills are used these mineral blacks are found 
to be very expensive, because they wU dull the sharpest 
mill in a few hours' run. As they possess very little 
tinctorial power it is more advantageous to use a 200- 
mesh silica, tinted with lampblack. 



CHAPTER X 

The Inert Fillers and Extenders 

These materials, which at times have been called the 
"reenforcing pigments/' have their value when used in 
moderate proportions, and yet it is not within the 
province of any paint chemist to say to what extent 
these materials can be classed as adulterants and to 
what extent they can be classed as inert fillers or reen- 
forcing pigments. In every case where this question 
comes up common sense, judgment, and best practice 
provide the answer. 

In the manufacture of mixed paints, with one excep- 
tion which \vill be described later, every mixed paint 
must contain an inert filler or extender, or else the paint 
will not remain in a ready-to-use form, but will set hard 
and lose much of its value. In white paints 45 per cent 
of zinc, 45 per cent of lead, and 10 per cent of asbestine 
are regarded as a standard formula, and 60 per cent of 
these pigments are usually mixed with 40 per cent of oil 
to produce the proper kind of paint. There are many 
instances where the inert fillers may reach as high as 20 
per cent, that is, to 40 per cent of zinc apd 40 per cent 
of lead or other white pigments, 10 per cent of gypsum 
and 10 per cent of white mineral primer, are added in 
order to give certain physical results; and yet there are 
any number of instances where more than half of the 
paint in question is composed of an inert filler, and the 
inert fillers under those circumstances cannot be regarded 



THE INERT FILLERS AND EXTENDERS III 

as adulterants. If we make a ready mixed paint of 
ochre we are taking a natural pigment which contains 
So per cent of clay, and no man can say that the clay 
naturally contained in ochre is an adulterant. In the 
manufacture of a flat wall paint in which lithopone is 
the principal pigment we have a pigment which contains 
70 per cent of artificial barium sulphate, and yet no man 
can say that this artificial barium sulphate is an adul- 
terant. In the Battleship Gray paint which the author 
de\ased for the United States Navy, it was found that 
the 45 per cent of zinc and 45 per cent of lead, with the 
addition of 10 per cent of black coloring matter, which 
was formerly used, gave very poor results, for such a 
paint was not salt-water-proof nor resistant to abrasion; 
but since the United States Navy has adopted the for- 
mula made by the author of 45 per cent of zinc oxid, 45 
per cent of blanc fixe, and 10 per cent of graphite and 
lampblack, a far better paint is produced which costs 
the Navy very much less money than the old type of 
paint. It is therefore not within the province of any man 
to say that the addition of this 45 per cent of blanc fixe 
constitutes an adulterant. Judgment, common sense, and 
the particular case involved must therefore decide the 
difference between pigment and adulterant. A large 
number of other cases can be cited, but these are suf- 
ficient to illustrate the point. 

The principal paint made which contains no extender 
and which remains in suspension is the well-known white 
enamel paint composed entirely of zinc, in which the 
medium is either a heavy bodied oil or a damar varnish. 
This paint needs no extender to keep it in suspension, 
on account of the very slight chemical action that takes 

• place between the acids in the oil or varnish and the zinc 

! itself. 



112 CHEMISTRY AND TECHNOLOGY OF PAINTS 

In spite of all the good qualities of white lead it has 
been impossible up to now to manufacture a ready mixed 
paint composed entirely of white lead without the help 
of an extender like asbestine or a slight saponification 
or emulsification by the addition of about i per cent of 
water. 

It is not so difficult to decide what constitutes an 
adulteration if we take the simple case of ready mixed 
white paint intended as a priming coat, which should 
have the maximum hiding power and physical qualities. 
If a paint like that were composed of 50 per cent white 
pigment and 50 per cent of barytes or whiting, it would 
not possess the physical qualities necessary for a good 
priming paint, and therefore the addition of this quantity 
of barytes would be strictly regarded as an adulterant. 

The principal fillers used in the manufacture of paints 
are as follows: 

Barytes Calcium Sulphate 

Barium Sulphate^ {Artificial) Clay 

Barium Carbonate Kaolin 

Silica Asbestine 

Infusorial Earth White Mineral Primer 

Calcium Carbonate Whiting 

G>'psum 

Barytes (Barium Sulphate, Natural) 

Formula, BaS04; Specific Gravity, 4.5 

Barytes is a white mineral having the same chemical 
composition as precipitated barium sulphate. In the 
United States Geological Survey Reports for 1904, the 
following statement occurs: *^The value of barytes as a 
white pigment is being recognized more and more each 
year, and although very little, if any, is used alone for 
this purpose, it is used in large quantities in combination 



THE INERT FILLERS AND EXTENDERS 113 

with white lead, zinc white, or a combination of both of 
these white pigments. This addition is not considered 
an adulteration, as was the case a few years ago, for it 
is now appreciated that the addition of barytes makes a 
white pigment more permanent, less likely to be attacked 
by acids, and freer from discoloration than when white 
lead is used alone. It is also believed that barytes 
gives greater body to the paint and makes it more 
resistant to the influences of the weather. As is well 
known, pure white lead 
when remaining in the 
shade or in a dark place 



becomes discolored, turn- /^•a'^*S ••.'i? *» W\ 
ing yellowish, while mix- //^ •• v '.* j,v ^ * * »! 






tures of white lead and 
zinc white, or white lead '•-T"'^(ft«# 
and barytes, or white lead, 

zinc white, and barytes T* •.».?- ^, 

retain their- color perma- ^^'^^^t' VVa^* 
nentlyeven in dark places," ^<t '. *. ' . • 

The amount of barytes 

^, ^ 1 -J .., No. 40. BAkYTES, irragular, broken crys- 

that can be mixed with uu-Ph^tomic^ph xjoo. 
colored pigments without 

injuring them is remarkably large. There are hundreds 
of brands of para-red paints made and consumed every 
year by the agricultural implement trade which contain 
as high as 90 per cent of natural barytes. When it is 
taken into consideration that these extremely diluted 
para-reds cover well and serve their purpose most admir- 
ably, the expert should be very careful not to condemn 
bar>'tes when used in large quantities, for this remarkable 
behavior is repeated with a large number of other pigments. 
No paint chemist will dispute the fact that barytes 
adds wearing quaUty to paint, but inasmuch as white 



114 CHEMISTRY AND TECHNOLOGY OF PAINTS 

lead has set the. standard for ease of working it is ad- 
mitted that all the other pigments and fillers are not as 
unctuous as white lead. Therefore the house painter 
will notice that the so-called lead combination^ which 
contains large quantities of barjrtes^ does not work is 
freely under the brush as white lead; nevertheless^ this f 
objection does not hold good when the barytes is used 
in moderate quantities, that is, not in excess of one third '. 
of the total pigment of a paint. An experiment was 
made with a mixture of one third carbonate of lead, one 
third zinc oxid, and one third barytes on an exposed wall 
of a high building in New York City, in 1885.^ Up to 
1905 this surface was still in a moderately good state of 
preservation, and as a comparison a wall painted in 1900 
with a -pure Dutch process white lead showed that the 
Dutch process white lead had not stood as well in five 
years as the combination mixture had stood for twenty 
years. It is conceded that no paint is supposed to last 
twenty years, but as a matter of record it is interesting 
to note that the inert filler added so much to the life of 
the paint which contained it. In view of this fact, the 
paint manufacturer is justified in recommending to his 
customers the use of inert fillers in his paint on the 
ground of increased longevity. 

One hundred pounds of barj^s will yield two and 
three-quarters gallons of paint. Owing to its crystalline 
structure and specific gravity it is a more expensive pig- 
ment to use than many others when sold by volume, and 
a paint manufacturer who uses barytes in a mixed p>aint 
and thinks he is the financial gainer thereby is very much 
mistaken, owing to the small volume which barytes . occu- 
pies in a mixed paint. It is also interesting to note from 
an experimental standpoint that if barytes be mixed with 

^ This building was demolished in 1908. 




THE INERT FILLERS AND EXTENDERS 115 

linseed oil and turpentine in the proportion of two pounds 
to a gallon it will be found that, on allowing these two 
pounds to settle in a glass jar where it can be observed, 
it occupies only 4 per cent of the bulk. In spite of 
much that may be said in favor of barytes, it is not 
better than some of the forms of calcium carbonate and 
some of the forms of silica. As an inert extender silica 
has advantages over barytes; namely, that while it 
produces the same physical effects with equal wearing 
quality, its cost is lower 
and it produces a surface ^ J!t^ J^^ 

for repainting, having what 
is' technically known as 
"tooth." 

Barytes is made from 
the mineral barite, and 
the principal deposits in 
the United States which 

are worked at present are \**^s ^'-"^l^*^*^^^ 
in Missouri, Tennessee, and '^(f%^ % •• • 

Kentucky. There are also *~ 

deposits in Virginia and ^^- ^'' ^^^^^""-^^ American- Photo- 
*^ ^ ® micrograph X300. 

in Georgia, and large 

amounts are also found west of the Mississippi, but 
freight plays a very important role in the shipping 
of barytes, and furthermore, only those mines nearest 
the surface can be worked at a profit. Barytes is not 
foimd in ledges or solid masses, but rather in isolated 
nodules. The pieces vary in size from an onion to a 
man's head, and vary in weight from one ounce to 
twenty or twenty-five poimds. There are, of course, 
larger isolated lumps foimd, but generally speaking this 
is the manner in which the material is mined. The 
mining of barite, as a general rule, is simply done in an 






Il6 CHEMISTRY AND TECHNOLOGY OF PAINTS 

open cut, and much of the barytes found in the United 
States is associated with a material called "chirt," which 
looks like barytes but can be very easily distinguished 
on account of its difference in weight. Chirt is a silicate 
of magnesia and alumina, and workmen very soon be- 
come adept in separating chirt from barite. Barite is 
usually contaminated with iron or with a sticky ferru- 
ginous clay, which can be separated by weathering or 
by washing. Some of the deposits in Virginia and 
Kentucky contain more than i per cent of lime and 
fluorine, which makes the ore undesirable for manu- 
facturing purposes but is not supposed to render it value- 
less as a paint base. To free it from iron it is bleached 
by what is known as the sulphuric acid process, but as 
it is generally washed, lixiviated, and floated after this 
treatment it is very seldom contaminated with any 
degree of acid. 

Barium Sulphate (Artificial) 

Synonym: Blanc Fixe, Lake Base, Permanent White; 

Specific Gravity, 4.1-4.2 

When a solution of chloride of barium is mixed wath a 
solution of sulphate of soda a heavy white precipitate is 
formed w^hich is known as artificial barium sulphate. 
In all of its chemical qualities it is identical with the 
barytes of nature, but in its physical qualities it is 
totally different. Depending somewhat on the method 
of its manufacture, the grain is exceedingly fine. 

Blanc Fixe has for years been used for the surface 
coating of paper, because when properly calendered it 
gives a very high polish and a permanent white surface. 
Originally it was a French product, the words "Blanc 
Fixe" meaning ^^ permanent white.'' In the early days 
of the paper industry various compounds of bismuth were 



THE INERT FILLERS AXD EXTE.WDERS 



117 



iised for coating the paper. There are still visiting cards 
in existence which were surface-coated by means of bis- 
muth carbonate and bismuth subnitrate. These cards 
were readily affected by sulphur gases, and when it 
was found that precipitated barium sulphate produced 
an equally high glaze and the surface retained its pris- 
tine whiteness the name "Blanc Fixe" was universally 
adopted for the new product. 

In the paint industry it was recognized that pre- 
cipitated barium sulphate 
was a valuable adjunct in 
the manufacture of paint, 
owing to the fineness of 
the grain and other physi- 
cal characteristics of the 
material. It was found, 
however, that when it was 
dried and powdered it had 
lost its extreme fineness 
and did not mix readily • I'v^^S" ; 

with oil paints. In 1895 N0.42. Blanc Fixe — Photomicrograph 
Henry M. Toch succeeded X3™- PtecipiUled from cold, dilute 
, . —., ■_. barium chloride. 

m making Blanc Fixe, 

which, when dry, was a soft, impalpable powder of 
great value as a base upon which to precipitate lakes, 
and, likewise, when used in mixed paints and enamels 
imparted to them, under proper conditions, a vitreous 
surface which improved their wearing quality. To this 
product the name of Lake Base was given. A great 
many paint and chemical concerns have succeeded since 
then in producing Lake Base of a soft fine texture, and 
it has become one of the established bases of the paint 
trade. Its intrinsic value, when properly made, is about 
half that of American zinc oxid, but a number of writers 




Ii8 CHEMISTRY AND TECHNOWGY OF PAINTS 

have erroneously stated that its body and covering 
capacity were equal to. zinc oxid. Lake Base is success- 
fully used up to 70 per cent in white pigments, and in 
colored pigments up to 95 per cent. It is amorphous 
under the microscope, and is used to a great extent to 
increase the spreading of weaker or coarser colors. 

Since 1906 artificial bariimi sulphate or Blanc Fixe 
has been used by nearly every paint manufacturer in the 
United States, for its excellent quahties have been proved 
beyond a doubt. The value of this material as a reen- 
forcing pigment or filler in the manufacture of paints has 
been thoroughly demonstrated by the elaborate experi- 
ments made by the United States Navy, another indica- 
tion of how futile it is for any man to say without careful 
consideration what shall be regarded as an adulterant 
and what shall be regarded as a piure material. In 1910 
the Bureau of Construction and Repair of the United 
States Navy had come to the conclusion that the Bat- 
tleship Gray, which had been in use since the termina- 
tion of the Spanish- American war — a period of about 
ten years — did not give good results. The formula for 
the Battleship Gray as it then existed was practically 
45 per cent of white lead, 45 per cent of zinc oxid, and 
10 per cent of lampblack. From the standpoint of purity 
this should be regarded as a very pure paint, and frora 
all precedent it should be inferred that a paint of this 
tyxxt would be the best that could be made; but two 
things demonstrated themselves beyond peradyenture. 
One was that such a paint was not hard enough to resist 
abrasion; furthermore, salt water in the form of spray 
or the water itself had a decidedly bad effect. When a 
paint of this tj^^e became wet it absorbed water, changed 
its color, and became very soft and spongy. The Navy 
officials most interested in this consulted the author, who 



THE INERT FILLERS AND EXTENDERS 119 

devised a paint which then would probably have been 
condemned by painters in general. Previous experience, 
however, had taught that the addition of large quantities 
of artificial barium sulphate or Lake Base to a proper 
pigment improved the entire value of the paint, to say 
nothing of reducing its cost over 20 per cent. As a result 
the formula decided upon by the author was: 45 per 
cent of zinc oxid, 45 per cent of Blanc Fixe or Lake Base, 
and 10 per cent of graphite and lampblack. The proper 
oils and driers were then added. A three months' test 
was made on the machine repair ship "Panther," and 
when this ship came back from a cruise it was found that 
the paint was sufficiently hard so that the anchor chains 
rubbing against the paint did not abrade it, and that 
the salt water, wherever it had wet the paint, did not 
produce any effect whatever. For upward of a year 
the Navy experimented in a small way painting other 
ships, imtil in 191 5 as much as several hundred thousand 
pounds of Blanc Fixe had been bought by the Navy for 
the manufacture of Battleship Gray. There may come 
a time when a new paint superior to the present one 
wall be devised, but this much has been absolutely proved 
— that a mixture of 45 per cent of zinc and 45 per cent 
of Blanc Fixe for sea water purposes is far better than a 
similar mixture made of zinc and lead only. 

At the time the Navy formula was originated Blanc Fixe 
was worth about 2 cents per pound, which made a con- 
siderable saving to the Navy. At the present writing, 
owing to the European war and the fact that only one 
concern is at present manufacturing Blanc Fixe in the 
United States from American materials, and that the de- 
mand is great and the supply small, the price has risen 
to over $85 per ton. If the price should rise as high 
as zinc oxid or lead itself, it is quite obvdous that in view 



^ decompi 

^^i^'J^/ ■***•/»;.•.•. stood thi 

*^^?-- .' ' A. t? * ♦ , ,■». •■ condemni 

•'iT • - .. •-* i'"^ '^'^^Sar written t< 



IZO CHEMISTRY AND TECHNOLOGY OF PAINTS 

of the purity of a paint made of Blanc Fixe the ques- 
tion of adulteration could not enter. It will therefore 
be seen that this question of adulterated pigments is all 
relative, depending entirely upon the results obtained and 
upon the cost of the material. 

As far as the influence of salt water on a paint made 
of Blanc Fixe is concerned, the writer had determined 
long ago that the action of sodium chloride (salt)' in the 
air or in water is one of the causes of the chalking or 
decomposition of white 
t must not be under- 
that the author is 
condemning white lead as 
i pigment. This is simply 
"irtpf* , written to show that there 
i-'*'.*.' **■"<■*' "".".■.•■ V ." ^^^ instances when other 
*. V, *'*•■'■■■* * •'ii.'v V I materials are better for a 
. '^■*y /^ .' ' '' .tf^y given purpose. 

•** ■' ^ k- > V'^- • Dry Blanc Fixe is des- 

* '**^ i"**'- ' tined to become a very 

,, „ ^ ' Du . ■ u useful paint material. In 

No. 43. Blanc Fixe— Photomjcrograph '^ 

X300. Prccipitaied from hot, con- 1905 there were probably 

centratcd acid solution of barium n^^ 0^^^ j^jq ^Q^g ^^ 

chloride. , , 

year used. In 1915 the 
use had risen to over 3000 tons per year, because the 
textile manufacturers had also found that its use in 
materials like linoleum and table oilcloth not only saved 
in cost of manufacture over the higher priced pigments, 
but produced more flexible and lasting materials. The 
same can be said of the printing ink manufacturers, who 
today are as large consumers of dry Blanc Fixe as the 
paint manufacturers. 

As regards the manufacture of Blanc Fixe, this has 
also changed within the last ten years. Formerly it was 



THE INERT FILLERS AND EXTENDERS 121 

known that only a solution of barium chloride and a 
soluble sulphate or sulphuric acid were the raw materials 
used for making this product, but today there are other 
methods which produce equally good materials, and in 
some instances better results than the chloride method. 
For instance, bariiun sulphide solution is precipitated 
with sodium sulphate, yielding a by-product, sodium 
sulphide, which can be sold at a considerable profit. 
The Blanc Fixe so made is denser than that made from 
the chloride. Blanc Fixe is also made from the peroxid 
of barium and sulphuric acid, but must be neutralized 
and freed from peroxid of barium before it is suitable for 
paint purposes. For certain color purposes the material 
is made from concentrated hot solutions, which produces a 
crystalline Blanc Fixe valuable for very brilliant colors, 
particularly greens and reds. Another method used is 
dissolving barium carbonate in nitric acid and precipi- 
tating with sulphate of soda, which then produces a Blanc 
Fixe equal to the chloride product. 

Barium Carbonate 

Foraiula, BaCOs; Specific Gravity, 4.2; Synonym, Durex White 

This material is practically new as a paint material, 
and has only come into use since flat wall paints have 
had such a tremendous success in the United States; 
and even at that, not very many manufacturers in the 
United States use it, although it probably is destined to 
become as useful an article as Blanc Fixe. 

Bariimi carbonate, under the microscope, has a very 
peculiar structure. It is not made by mixing a solution 
of barium chloride and sodium carbonate, although that 
would be the normal way of making it, but it is made 
from bariimi sulphide and sodium carbonate in fairly 



133 CHEMISTRY AND TECHNOLOGY OF PAINTS 

concentrated solutions, so that the sodium sulphide be- 
comes a valuable by-product, and therefore the barium 
carbonate can be successfully marketed at a reasonable 
price. 

In hiding power it is between Blanc Fixe and zinc 
oxid, but when used in the proportion of 45 per cent 
barium carbonate and 45 per cent of zinc oxid or litho- 
pone in a flat wall paint its physical quality makes it 
particularly valuable, because the resulting paint with 
the proper thinners pro- 
j K^ * -• j-^V . duces a velvet finish imap- 

^-j 1^^-\ •?'" ' *y* *- preached by anything else. 
'""""' ' * Barium carbonate such 

; sold for paint manu- 
f^''^''!^ \i'y^!'K\*'''^Ki' ^^"^turs must not be con- 
founded with Witherite, 
the natural form of ba- 
% *W>jf"-'''' ji^T* '/y rium carbonate. This is 
*"'*^*,fj "I.'.*^.*-; '.^-^^ not found in the United 
*, *^*^**i*' States, but is largely 

** ' mined in England, Austria 



.,^'rv:>-V^4'-^.'^t^ -is 
r-^rvV'-'^^^^J^^ ^-tu 

ii^.ff :,:>'^yt Vv^T* 'o™< 



""'■'^ and Germany. Witherite 
has absolutely no paint 
qualifications, and is not even as good as barytes. 
In composition Witherite is identical with the artificial 
barium carbonate, but under the microscope powdered 
Witherite is a transparent crystalline material similar in 
appearance to table salt. 

Silica 

Formula, SiOj; Synonym, Infusorial Earth, Silex 
The introduction of silex in paint is due to the 
researches and investigations made by David E. Breninig, 
M.I)., who in the early fifties had noted that when white 



THE INERT FILLERS AND EXTENDERS 



123 



lead was mixed with barytas it stood exposure better 
than pure white lead. Late in the fifties he came across 
some rock crystal quartz, 
and, on grinding and mix- 
ing it with white lead, 
found that it improved 
the paint. The prepara- 
tion of silica, especially for 
the paint trade, became 
an established industry 
between 1865 and 1870. 

The earher process for 
powdering quartz was the 
simple and economical 
method of dry grinding 
by the tumbling process. 
The quartz was simply crushed to a granulated state and 
then put into a tumbling barrel with pebbles, which was 
^ . revolved until the. silica 

•^ ''^N^^ was reduced to a compara- 

X *». tively impalpable powder. 
,^ J- «► ^^ It was found, however, 
B v5 '.- \ that this method was not 
M ,^' f* * satisfactory', because it did 
, f) ' ^ ^ ^ot produce uniform re- 




No, 45- Silica, or Silkk — Photomicro- 
graph X2SO, ver>- fine grain. 



- «» *' 

'\^.. 






V ■ <^■T/^^ ^ ' suits, and the Silex Lead 

\^ ii' ff^ "^ Company, which had been 

^, ^ , . '^ V J ■ formed for the manufac- 

" ' ture of silica or silex for 

the paint trade prior to 
1870, adopted the process 
of heating the quartz to a 
visible red heat, plunging it into water, and crushing it after 
the sudden change of temperature had split the silica into 



No. 46. Silica — Photomicrograph x 2 50, 
finely powdered and air floated, uniform 
angular giain. 



124 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



a finer state of division. The silica was ground in 
tubs under water with stone bottoms and drag stones, 
and after it had been thoroughly comminuted it was 
washed, floated, dried, and then bolted to a given degree 
of fineness. There can be no question that the prepara- 
tion of silica in this manner produced a material al great 
uniformity, the value of which in paint is unquestioned. 
In the early part of the seventies the first practical tests 
were made on the coast of Maine. It was found that 
pure white lead would not 
stand exposure at the sea- 
shore for more than a year. 
At the end of this time it 
resembled whitewash and 
presented a poor surface 
for repainting. A mixture 
was made at that time of 
one third silica, prepared by 
heating and washing, one 
_ third zinc oxid, and one 

N0.47. Silica — PhotomicrotcraphXJSO, third whltC lead. ThcSC 
verj' fine grain; this material has been materials WerC grOUnd to- 
Cround in water. .-i • i- j -i 

gether m pure Imseed ou 
and Sufficient drier added. At the end of seven years 
this paint was still in good condition and presented an 

excellent surface for repainting. 

Silica, like many of the inert materials, has the added 
physical advantage of presenting what is known as a 
"tooth," which fits it exceedingly well for repainting. 
Silica is inert as an extender or filler in paint, and does 
not combine with any other pigment or vehicle. The 
detection of silica in mixed paints is very easily accom- 
plished by means of the microscope and Nicoll Prism, as 
the metallic pigments do not polarize. In chemical 




THE INERT FILLERS AND EXTENDERS 125 

analysis we often find i per cent of silica in an otherwise 
pure paint. This i per cent of silica generally shows 
up in large arrow-head crystals scattered throughout 
the field of the microscopic vision, and is due to 
very small particles of silica which have been worn oflF 
from the grinding stones of the mill. The amount of 
silica which may be safely added to many colored mixed 
paints without detracting from their covering properties, 
and which will increase their wearing qualities, is less 
than one third of the total pigments used. 

The composition of the various silicas on the market 
is quite uniform, and those that are made from clear 
colorless quartz, or faintly colored quartz, are practically 
free from iron. Silica made from rock quartz will assay 
99.7 Si02. 

Infusorial earth is almost pure silica and is largely 
composed of the skeletons of diatoms. It is exceed- 
ingly bulky, and is used by some paint manufacturers 
to prevent the settling or hardening of paint in cans, and 
owing to its light specific gravity it accomplishes this very 
well when added in even as small a quantity as lo per 
cent. 

The question comes up occasionally as to whether 
silica will hydrate when heated and thrown into water. 
This question must forever be settled by the fact that 
analyses of silica treated in such a manner show it to 
contain 99 per cent Si02. If any hydration took place 
it would be evident in the quantitative analysis. There 
can be no doubt that the silicas obtained on the market 
which are washed and treated are therefore pure SiOo. 
The silicas made from infusorial earth contain a varying 
percentage of moisture, but the balance is almost pure 
silica. 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



Infusorial Earth; Kieselguhr; Fut-ler's Earth 

Infusorial Earth, Kieselguhr, and Fuller's Earth are 
forms of silica which are diatomaceous in nature. Di- 
atoms are the - remains of plant life — the silicious 
skeletons — the organic matter having been entirely de- 
composed, leaving these skeletons. The forms of these 
skeletons are wonderful, and a number of Illustrations 
will show what they are like. Some are like beautiful 
chased jewels or fihgree 
work; others are like the 
covers of boxes made of 
lace work; and still others 
are spear-shaped, but all 
_^^ of them have the quality 
^ti/'Xx ^^"^'^' jfe^SH more or less of absorbing 
^^ . ^-^ '-^ ^»aj^^y dyes. They are not pure 
^» , «»_ ^ ^gk^r silica, for some of them 
^F _-/'*. k. ^ji^ are largely composed of 

silica and silicate of alu- 
mina or sihcate of mag- 
nesia. 

These materials are 
used both as bases for the lake colors used in making 
pigments, and for the purpose of preventing the settling 
of certain classes of mixed paint, particularly the first 
coats which are not so finely ground. In this respect 
these materials are frequently substituted for asbestine, 
because they are more or less free from moisture or 
water in combination. They can be readily identified 
under the microscope on account of their very peculiar 
and beautiful forms. 




. Infusorial Karth — Photomi- 
crogroi>h X150. 



TBE INERT FILLERS AND EXTENDERS 



137 




Clay 

Composition, Silicate of Alumina; Synonym, Kaolin, Fuller's Earth 
Clay in small quantities is very largely used by paint 

manufacturers, first, to prevent settling or hardening 

of mixed paints, and sec- 
ondly, to produce unctu- 

ousness or good brushing 

qualit>'. Clay occurs natu- 
rally in many paints up to 

as high as 80 per cent, as 

for instance, ochre, which 

is 80 per cent of clay and 

20 per cent of coloring 

matter. The siennas a!! 

contain clay up to as high 

as 60 per cent, and as 

clay is found naturally in 

the pigments referred to 

they cannot, of course, be regarded as adulterated, but 
when large quantities of 
clay are added to other- 
wise good paints the wear- 
ing quality is reduced, and 
therefore more than 10 or 
15 per cent is not advis- 
able. Clay always contains 
a large percentage of water, 
and the emulsification that 
ensues probably aids in the 
non-hardening qualities of 

No. so. uiATOMs — Photomicrograph paint. In paste paints of 

x6oo, frequently found in whiling. ., , 

the cheaper vanety, par- 
ticularly barrel paints, clay becomes a necessity, for these 



So. 49. Diatoms — Pholomicrograph 
X300, found in whiting, clay, and 
infusorial earth. 



\ 



■'■*i, 



128 CHEMISTRY ASD TECHKOWGV OF PAINTS 

paints are sold at a very low price, and must remain 
soft indefinitely and easy to mix. 

Kaolin is a type of clay which is used by the pottery 
trade; a typical analysis is as follows;' 

SiO- 46-27% 

AijOj 38.57% 

■ Feja.--.- 1.36% 

CaO 0.34% 

MgO 0.25% . 

Na-0 0.37% 

HjO 1 3.61 % 



It has practically the same physical value as the 
ordinary clay, excepting that the pottery clay is usually 
whiter in color. Clay has 
y^jNf*"^'\^ no hiding power or opacity. 

Kaolinite, 2SiOi ■ AliO, ■ 
2H2O, is the principal con- 
stituent of kaolin. 

AsiiESTINE AND ASBESTOS 

.\sbestine and eisbestos 
arc silicates of magnesia, 
ihc asbestine having a 
short fibre and the asbes- 
tos having a long fibre. 
Asbestos fibre is used 
to a small extent in paint, but it is not as good as 
asbestine, because the fibre of asbestos is too long. 
However, considerable quantities of asbestos are used 
for the making of so-called "fire-proof" paints, and on 
this subject it is proper to say that there is no such 
' Bull. :,$' (l-''^- Gcol. Sur\'.), Cluys of .Arkansas, p. 21. 




i|jh X300. 




THE INERT FILLERS AND EXTENDERS i2g 

thing at the present time as "fire-proof" paint. It 
is perfectly possible to make a fire-resisting paint, but 
these paints usually are 

of the casein-whiting type. j^ "^"^ . ^W 4 

Casein, lime, phosphate of z_.*— *.•. 'J**' »* <« 
soda, and whiting, which 
when mixed with water 
produce fairly good 
mine, resist fire for i 
while. A typical experiment 
has always been to i 
small shingle, paint 1 
it with a so-called "fire- 
proof" paint, and ignite ., ^ ^ „^ . 

*^ r J D jjq jj^ Chin-a Clay — rhotomicrograph 

the uncoated part; the fire xjoo. 

dies out when it reaches the painted part. This can 
be done with a piece of wood from ^V to j inch in 
thickness, but no timber or board of any size can pos- 
sibly be rendered fire-proof 
_-^g ;V/^1| [ by paint application, for 

%^^*'^t *i.*'.V'-''»*>s when such a piece of wood 
M^' • '-** * '-liw^ I J t> ^ or timber is subjected to 
*^..i/ * ■ li^^^ ''^E^^ ■ ^"ffi'^i^"* heat, distillation 
i'j'TzM^'.'^-i'f^^Sk*^ £« **^ ^^^ uncoated wood on 
5-1* u'?'M'''^«3^-5'Jb'i'i^ the inside takes place, gas 
^>J^^ ' * ' *!• ^i- « C'-- - '^ generated, and the wood 
<il^''.^,fi^v"L/3f*— .■? ' ' bursts into flame. Theonly 
'•"'^■itl«,^'.*W'^^' successful method of treat- 
■ \ *'^p '*■■ •• * ing wood to prevent it from 

* ■ burning is by impregnat- 

N-o. 53- CoLL«iD«. Claj— Pholomicrc^ ■ ^^^^^ ^^^ ^^^^ , 

graph xjoo. ° ■' 

means of a vacuum pro- 
cess; but this is not painting, because the crystallizing 
eflfects of the fire-proofing material destroy or peel 



4^^ 



I30 CHEMISTRY AND TECHNOLOGY OF PAINTS 

any subsequent paint or varnish, so that up to now 
there has been no fire-praof paint made which ren- 
ders wood structures fire- 
^fj|'#"^. proof. 

/ i. ^ , " ,. f^ ■■■ For the painting of 

^ iTi r ^#Hw«h '■ ■ 'V shingles where sparks may 

' ■■is.' .. ^' ■■" " ' «0 ^\ ' possibly ignite them, oil 
f ■Jr^6J-'. ■ /'y, ■ ■■■^Jj>u; « paints containing boracic 
-,.■■" , , , v -.d acid and powdered asbes- 
gjiv^i/", !JI\ "^ >..' ■i'.*j» tos are used, as a paint 
^^ ' y, - . J'''t ->, >/ of this type resists sparks. 
^\^' i^fc^^ate^.^. Asbestos can be very 

'^^^^_j^5''^ '^ readily identified under the 

No. 54. AufcSTist — PhotomicroRraph microscope on account of 
^^°°- its long fibre. 

The average analysis of asbestine is: 

SiOa 62% 

MgO 31% 

CaO 3% 

Water of Crystallization 4% 

100% 



Calcium Carbonate 

Formula, CaCOj 

Synonyms: Whiting, Paris While, Chalk, Marble Dust, Artificial 

Calcium Carbonate, Spanish While, and White Mineral Primer 

Whiting and natural calcium carbonate are prepared 
from the natural chalk deposits of the cliffs in the south 
of England, and Paris White, Extra Gilder's White, and 
Spanish W'hite are all different qualities of whiting, de- 
pending on the amount of levigation and fineness of grain. 
The mode of preparation is very simple. It consists in 
grinding the cliffstone in water, washing it, and allowing 



tHE INERT FILLERS AND EXTENDERS 131 

it to settle in large vats. The cream, or that which is 

nearest the surface, is dried over steam-pipes, bolted, and 

sold as Paris White. The 

next layers are sold under 

the name of Extra Gilder's 

White, and the bottom 

layer as Commercial White, 



of which putty is made. ''V^'*^i^!i:-J?^ v;-^^ 

Whiting is a neutral calcium jt-*^^* i,»X^« '^••^?^?-''r'•^3ff 

carbonate, and with the *iJ*,|\VV^>'a*';"^''i;'^.-r^rt* 

exception of the small per- ^V;A^'l*-2;;^'-^iwt%^ 



■ Photomicrograph 
X300. very uniform grain. 



centage of water, which is 
very variable and depends 
upon how thoroughly it has ^°- ss- \\ 
been dried, it is remark- 
ably pure and fine. The material at the bottom of the 
tubs known as Commercial Whiting is ne\'er used in 
the manufacture of mixed paint, because it is coarse, 
contains silica and iron, 
and in attempting to grind 
this grade the mills are 
ruined. 
' '» w b ' There is a great difter- 
p-T »'*dM&*A** ^"<^^ of opinion as to the 
' i^^Jf]li»i^ merits of whiting in paint, 
"^^" jlv^? ^"^ '^ ^'^ ^^ conceded 
.'.I-*' by every manufacturer 
and paint chemist that 
the addition of calcium 
carbonate in some form 
r other is of great benefit 
o mixed paint. Some 
manufacturers put 5 per cent in all the paint they make, 
excepting that which is made according to specification. 




No. 56. Gilder's Whttiko — Photomi- 
crogi^fh X300. 



133 CHEMISTRY AND TECHNOLOGY OF PAINTS 

for the excellent reason that any acid which may either 
develop in the paint or be a part of the chemioil com- 
position of the paint is 
slowly neutralized. For 




5Jt'5?y4>tfNl^. paints intended for the 
-a^'?>"-»?^*'^^>»5^ protection of metal this 
n jr. ^^;4"..TV*^iYf**» T^ practice is to be highly 
j^;V / * ^i^'^.^L^^** J'ecommended. On the 
I other hand, some writers, 
who, however, have had 
little or no practical ex- 
perience, condemn calcium 
carbonate in any fonn be- 
cause it lacks covering 

"'■ "-PL'S™ SZr.^'""'*" -P-i'y o^ Wdtag power. 
If a paint were made of 
ICO per cent calcium carbonate this statement would 
hold true, but where other solid pigments are added 
the argument against whiting fails. No particular evi- 
dence need be brought to 
bear to prove the durability 
of whiting, for the reason 
that all putty is made of 
whiting and oil, and there 
are buildings and farm- 
houses in any number still 
existing where the putty, 
after being exposed to the 
elements an\nvhere from 
twenty-five to sc\'enty-five 
years, is, if anything, better N«- sS- Talc (Soapstooe) — Phow- 
at the end of that period 

than one month after it was applied. Whiting has the 
added advantage of being bulky, and priming coats in 




THE INERT FILLERS AND EXTENDERS 133 

which it is used present a good surface for repainting. 
The amount that can be used as an assistant to mixed 
paint is very variable, de- 
pending largely on the pig- 
ments used or shade which 
is made. Where a paint 
is to be made for the in- 
terior of a building in 
which acid fumes are gen- 
erated whiting should, of 
course, be omitted. But 
there are so many excel- 
lent fillers that the use of 

jle one is not always no. 59- rasic jiagnesiuu carbonate 




necessary. Whiting as it ^ l'hot<,mict<.Braph xjoo. lixlremely 
,^ , . light and fluffy. 

IS made today is never 

alkaline, for in the drying process it is placed on steam- 
pipes and the temperature is so low that decomposition 
cannot take place. 
r*.^^*mhi^.>^■'■ -. The other forms of cal- 

^\i-.\-'/*>^^J^''*^'^ cium carbonate which are 
,^ -"*o^*-J*. V* -.V^' '•^"'' - ^^ "^^ ^""^ produced by 
y ;J'i '^1 •* •'.'■V '^'^•''"l grinding white marble very 
"-^"t/ "..'*" f'\Vt':.N*V?'.,''\(%' fine, and, generally speak- 
>vCjt>;_»:^'-t"t.j,*.--V(.'^' V^-i ing, these varieties are 
'^\'^i^;u->'; X*.\v-,tLf. '*j better for mixed paint pur- 
* •» V. ^i^'^^X.* > ff JV'^' poses than the whiting 
^•^''i-i'^^^^'^V^* made from chalk. In the 
^y^t*^^\ /-- ' first place, the ground 

X(i. 60. Aluuisa Hydr.\te, used as a marble or Hmestone con- 
base for printing ink colors— Photo- tains Httle or no moisture; 

micrograph xjoo. • ^l j i .l 

m the second place, they 
are ground exceedingly fine, and being angular or crys- 
talline in shape they form a better surface, if anything. 



134 CHEMISTRY AND TECHNOLOGY OF PAINTS 

for repainting than whiting; and third, where an absolute 
chemical composition is wanted they produce more uni- 
form chemical compounds. Whiting and white filler 
compounds bulk between 3f and 4I gallons per hundred 
pounds of dry unit. 

There is another grade of calcium carbonate which 
occasionally appears on the market and is a by-product, 
principally from soap works. It has all the physical 
characteristics of a good article, but its chemical char- 
acteristics condemn it at once as a paint material on 
account of the free lime which it contains. It is worth- 
less for the purpose of making putty and useless as a 
paint filler. When putty is made of it, it forms a lime 
soap and gelatinizes the contents of the packages. 

White Mineral Primer 

This is a white crystalUne limestone which is found 
chiefly west of the Mississippi, and more largely used by 
western paint manufacturers than by eastern, for the 
freight is against its shipment to eastern points. 

In physical structure it is similar to barytes, but of 
much lighter gravity and greater bulk. For instance, 
100 pounds of white mineral primer will yield 4.6 gallons, 
while 100 pounds of barytes will yield 2I gallons. White 
mineral primer has very little opacity or hiding power, 
but it has the physical quality of "tooth," and when 
mixed with zinc or sublimed lead it is superior to any 
other form of whiting, wdth perhaps the exception of the 
artificial calcium carbonate. In many respects it is similar 
to finely powdered marble dust. 

Marble Dust 

Considerable marble dust is used in certain forms of 
paint, marble dust being chiefly composed of calcium 



THE INERT FILLERS AND EXTENDERS 135 

and magnesium carbonate with i or 2 per cent of 
ferric oxid. It is a brilliant white, and when passed 
through a screen of 200 mesh is similar to white mineral 
primer. Its chief use is for carriage and coach paints 
and also as a primer for wood generally, because it pre- 
vents peeling on account of its structure, having the 
same properties of "tooth" which are ascribed to silica 
and white mineral primer. 

Spanish White 

Spanish White is similar in all respects to powdered 
chalk, Paris White, or whiting, and at the present time 
is a name only, for there is little or no whiting for paint 
purposes that is now imported from Spain, all of it being 
of the cliffstone variety from England. 

Artificial Calcium Carbonate 

This material has already been referred to. It has 
very excellent properties, but usually has the one great 
defect, viz. the small percentage of free alkali both 
of lime and soda which it contains, and this produces 
"livering" of paints. Wherever it can be obtained in 
neutral form it is excellent when added in small quan- 
tities to many priming paints. 

Gypsum 

Formula, CaS04+ 2H2O 

As an inert pigment or filler gypsum is very largely 
used in the United States. It is found in twelve states 
and in very large quantities in Canada. Its specific 
gra\'ity is 2.5 and its formula as cited above is CaS04 
plus 2H2O. This formula represents the gypsum of 
commerce, as sold to the paint trade, so closely that the 



136 CHEMISTRY AND TECHNOLOGY Of PAINTS 

percentage of water in several samples averaged over 19, 
whereas the theoretical is 2Q.2. 




No. 61. AUERICAN Gvpsuu — Photo- No. 6», AuEKiCAN GvpsuH — Photo- 
micrograph X150, fairly uniform nucragraph X300, tian^uicnt flat 
and flat crystals. crystals. 

There is a great difference of opinion as to the merits 
of gypsum as a paint filler, for it must be borne in mind 




No. 6j. .VuERiCAN Terra .'Vlba — Pho- No. 64. Calciuu Sulphate (Gypsum) 
lomicrograph 150, very finely pow- — Photomicrograph X«50 {.\meri- 

<i.Tcd. can). 

that if it contains any free lime, or if it is not fully 
hydrated, the lime will act injuriously on the paint and 



THE INERT FILLERS AND EXTENDERS 137 

thicken it unduly. The defect produced by its incom- 
plete hydration will be to take up moisture from other 



•JL^. 






<4.. 



i^ 




No. 65. Frexch Terra Alba.— Pho- No. 66. TtRBA Alba (French Gypsum) — 
tomicroKraph xaso, composition Photomicrograph x6oo, showing co'S- 
CaSOt + a HjO, same as g>psiiin. talllne structure of calcium sulphate. 

materials in the paint so that a hardening or setting 
process goes slowly on. 

No. 67. Calcium Sulphate — Photo- No. 68. Precipitated Calciuu Sul- 
micrograph X300. Ppted, from cold, pbate — Photomicrograph y.joo. Note 

moderately concentrated solutions. the long- fibred crystalline structure. 

Some of the gypsum sold in the east is made from 
alabaster, this being a native, translucent calcium sul- 




138 CHEMISTRY AND TECHNOLOGY OF PAINTS 

phate. The Pennsylvania Railroad in its freight car 
color permits the use of 70 per cent of gypsum, and as 
good results have been obtained by this company in the 
use of calcium sulphate as a filler the condemnation of 
this material is without much foundation. Due con- 
sideration must be given to the fact that thousands of 
tons of Venetian red are consumed by the paint industry 
every year, and that the composition of Venetian red 
wall average from 15 to 40 per cent ferric oxid, the 
balance being entirely gypsum. It is nevertheless true 
that as one part of gypsum is soluble in five hundred 
parts of water, excessive rainfall will erode it in a paint, 
particularly where the binder is easily attacked. 

Where calcium chloride is a by-product large quan- 
tities of calcium sulphate are artificially made, and many 
paint manufacturers prefer the artificial calcium sul- 
phate to the natural. The photomicrograph shows this 
to have a long^fibred crystalline structure, and while 
it has no chemical properties which are different from 
the natural gypsum, its purity and physical structure 
make it valuable for many mixed paint purposes. 



THE INERT FILLERS AND EXTENDERS 



139 



Composition of Various Samples of Gypsum 



CALCIUM 
SUXPHATE 


WATER 


7745 


20.14 


77.79 


21.39 


78.44 


20.76 


77.46 


20.46 


79.30 


48.84 


64.63 


18.75 


67.91 


17.72 


71.70 


18.68 


59.46 


16.59 


69.92 


18.85 


69.26 


21.50 


64.22 


14.00 


76.02 


19.00 


77.76 


20.28 


76.44 


20.02 


78.60 


20.31 



PERCENTAGE 
OF GYPSUM 

94.09 

97.59 
99.18 

99.20 

97.92 

98.14 

85.63 
90.38 

76.05 
88.77 
90.76 
78.22 
88.80 
72.60 
95.02 
98.04 

94.84 
96.46 

98.91 



AUTHORITY 

Conn. Exper. Station 
Orton, Ohio Survey 
David T. Day 
G. E. Patrick 
E. H. S. Bailey 
E. H. S. Bailey 
E. H. S. Bailev 
E. H. S. Bailey 
Okarche Cement Co. 
E. H. S. Bailey 
Paul Wilkinson 
U. S. Geo. Sun'ey 
Wilbur G. Knight 
Calif. Exper. Station 
Calif. Exper. Station 
G. P. Grimslev 
G. P. Grimslev 
Conn. Exper. Station 
Conn. Exper. Station 
G. P. Grimsley 



CHAPTER XI 
Mixed Paints 

We have seen from the foregoing chapters the ma- 
chinery necessary for the manufacture of mixed paints 
and the raw materials most generally used. 

Of all the shades of mixed paints made, the white 
paints are the weakest and perish the most quickly, and 
the black paints, particularly those high in carbon and 
the ferric oxids, are those which last the longest. It is, 
for instance, impossible to state which of the white paints 
is the best, and individual opinions or single instances 
are not permissible for comparison. A test of white 
lead at the seashore will show that white lead is not 
as good as other white pigments, and at the same time, 
in a test in the interior of the country, or where climatic 
changes are not generally marked, white lead will show 
up wonderfully well. As an instance of this, it may be 
cited that the United States Light House Department 
ordered their white mixed paint to be composed of 75 
per cent zinc oxid and 25 per cent white lead, for at the 
seashore this mixture is better than either pigment alone. 

A series of experiments conducted by the author 
showed that white lead perishes through the action of 
carbon dioxid in rain water. As soon as a film of oil 
becomes vulnerable the white lead becomes soluble in 
the rain water, the so-called chalking being traceable 
to this cause. Zinc oxid is also attacked by carbon 
dioxid, but not nearly as quickly as white lead. Sub- 
limed white lead is attacked still less than zinc oxid and 

140 






MIXED PAINTS 



141 



zinc lead. The western zincs and leaded zincs, which 
vary in their proportion of lead sulphate, are slightly 
more permanent than zinc oxid, but the moment an inert 
filler such as barium sulphate, either precipitated or 
natural, silica or magnesium silicate, are added to the 
white lead and zinc oxid paints, their resistance to atmos- 
pheric influence is largely increased. Therefore these inert 
materials are an improvement to paint, and where no 
specification is to be followed they cannot be regarded 
as adulterants. The principal reason why these inert 
fillers are not added in greater quantities to white paints 
is due to the fact that the consuming public is not yet 
sufficiently educated to the use of such materials. 
Lithopone has proved itself an extremely valuable pig- 
ment, particularly for floor paints and for marine 
paints where shades other than white are demanded. 
In no sense can the 70 per cent of barium sulphate 
which is contained in lithopone be regarded as an adul- 
terant, because it is a constituent of the paint itself. 

The carbon and graphite paints have wonderful 
powers of resistance, provided they are properly diluted 
with a heavier pigment so that the film is thicker. 
The average graphite paint will cover one thousand square 
feet to the gallon, but the film produced is so thin that 
when it once starts to go, either through the abrasive 
influence of the solid contents of the atmosphere or the 
decomposing action of water, the surface is soon exposed; 
but when many successive coats are applied to produce a 
sufficient thickness far better results are obtained. 

The ferric oxid paints strike a happy medium, for 
they cover from four to six hundred square feet to the 
gallon ; but their color is limited to three shades — red, 
brown, and black. As priming and second coats they 
are, however, ideal, and as finishing coats where 



142 CHEMISTRY AND TECHNOLOGY OF PAINTS 

these shades are admissible they serve their purpose 
exceedingly well. 

No single pigment is as good as a mixture of pigments, 
and the intelligent combination of the raw materials 
always produces the best results. 

There is continued rivalry between the manufacturers 
of the lead pigments and the manufacturers of the zinc 
pigments, both of whom claim superiority for - their 
particular pigments. If you read the advertisements in 
any of the weekly journals or in the paint magazines 
you will see after reading one advertisement that only 
white lead is the best pigment, and after reading another 
advertisement that only zinc oxid is the best pigment; 
but competent investigators who are more or less honest 
hesitate to say that zinc oxid is better than lead, or 
that white lead is better than any other pigment. As a 
matter of fact, it is a very difficult thing to decide; 
a just decision would be that they are all excellent. 
White lead, of course, stands supreme for hiding power. 
There is no pigment with the exception of lithopone that 
will show as much opacity as a single coat of white lead. 
On the other hand, there is no material that has such 
wonderful qualifications for enamel-making as zinc oxid, 
and, as a matter of fact, the only single pigment that can 
be used and is used for certain purposes is zinc oxid, all 
the others being unsuited for the manufacture of prepared 
paints on account of their gravity. It has been con- 
tended that white lead alone mixed with the proper oil 
and driers has stood for many years, and this is quite 
true; but zinc oxid alone, as a pigment at the seashore, 
does not give as good results as white lead, because zinc 
oxid dries too hard; and yet, from the large experiments 
made by the author, a mixture of the two is unques- 
tionably better than, any single pigment, although 



MIXED PAINTS 



143 



failures of mixtures are perhaps as frequent as failures of 
single pigments. 

That mixed paints have become a necessity is evi- 
denced by the fact that considerably more than one 
hundred million gallons have been made in the United 
States since 1907. The exact amount made at the pres- 
ent time is very difficult to determine, but it has been 
estimated as being over one hundred fifty million gallons. 
At the same time, the production of lead has increased, 
and the production of zinc pigments likewise. Likewise, 
the production of both the sublimed white lead and of 
the sublimed zinc and lead of the Ozark type are increas- 
ing, and have come to stay, so that the criticisms of the 
various pigments are more or less a question of com- 
mercial rivalry rather than an inherent defect in any 
of the pigments. They all serve an excellent purpose 
and all are exceedingly useful. 

Many manufacturers of mixed paints guarantee that 
their paints will stand five years under ordinary con- 
ditions in the United States. This guaranty is prob- 
ably excessive, for there are many details which on> 
their face appear insignificant and are not taken into 
account by a manufacturer. 

The priming of wood has much to do with the life 
of paint, and a paint that contains much oil or vehicle 
to which either pine oil or benzol has been added, 
so that penetration into the wood can be effected, will 
give much better results than very heavy paints con- 
taining only 40 per cent of vehicle and 60 per cent of 
solids. For the priming of wood this proportion should 
be reversed and the paint should contain at least 60 
per cent of liquids and 40 per cent of solids, to which for 
raw new surfaces a penetrative solvent like benzol, toluol, 
or pine oil should be added. 



\ 

144 CHEMISTRY AND TECHNOLOGY OF PAINTS 

On the other hand, the oxid of iron paints such as 
Princess Mineral or Prince's Metallic have been known to 
last twenty years on wooden barns in the country dis- 
tricts; this is undoubtedly due to the fact that a reduced 
oxid of iron of the Prince's Metallic type is not affected 
by gases, nor does it react on linoxyn. As cottages, 
villas, and private residences are never painted a dark 
brown or a deep red like any one of the ferric oxic com- 
binations, it is therefore proper that this discussion relate 
entirely to the lead and zinc pigments which are most 
largely used for the purposes mentioned. 

Anti-fouling and Ship's Bottom Paints 

Anti-fouling and ship's bottom paints are always 
sold ready for use, and there are two distinct types, — 
the copper paints and the mercury paints. 

There is a continual difference of opinion among both 
consumers and manufacturers as to whether the anti- 
fouling type of paint should be one that does not dry and 
be of the exfoliating tjpe, which means that it contains 
lard or tallow and that when the barnacle or seaweed 
attaches itself it drops off by its own weight, or whether 
the paint should be of the poisonous type, so that when 
the barnacle or submerged growth has absorbed a suf- 
ficient quantity of the poison it dies and drops off. 
This is a much mooted question, and there is much to 
be said on both sides. Naval Constructor Henry Wil- 
liams of the United States Navy has probably done more 
work on this subject for the American Navy than anyone 
else, and his tvqie of paint which contains the red oxid 
of mercury has undoubtedly given far better results than 
any other anti-fouling paint. The composition of the 
paint used by the United States Na\y is as follows: 



MIXED 


) PAINTS 


U. S. X. 


Anti-Fouling Paint 


6i gals. Shellac Varn. 


15 lbs. Zinc Oxid 


4 '' Den. Ale. 




5 " Blanc Fixe 


2\ " Pine Tar 




25 " Indian Red 


2\ " Turps. 




10 " Red Oxid Mercury 


Yield : 




15 gals. 



145 



The copper paints which are found on the market con- 
tain from 10 percent copper scale (copper oxid — CuaO) 
to as high as 40 per cent. As a rule, this is added in a 
ver>' fine powder to a mixture of linseed oil, pine tar, 
benzol or gas house liquor, and oxid of iron in some form, 
usually of the Prince's Metallic type, is added as a 
pigment for hiding power. This is a so-called red or 
brown copper paint. The green anti-fouling is generally 
a copper soap manufactured by saponifying either linseed 
oil, tallow or fish oil with caustic soda, and then adding 
sulphate of copper to this soap, which produces an oleate 
or linoleate of copper and sulphate of soda as a by-product. 
The sulphate of soda is washed out, the remaining water 
boiled off, and then pine tar and linseed oil added to the 
mixture together with chrome yellow and Prussian blue 
for hiding power. This yields a semi-drying or non- 
drying type of green anti-fouling, which in many instances 
has given excellent results, but which in some tropical 
waters does not show up as well as the oxid of copper 
paint. The copper paints do not show up as well as the 
mercury paints. 

There is a third ty^^e which is not a paint, but which 
is really a soap that is applied hot. Oleate or linoleate 
of copper mixed with China wood oil when melted and 
applied to a thickness of about iV to \ of an inch has 
given very good results, and it is stated that this tjpe 
of copper paint is a happy medium and possesses both the 
exfoliating and the poisonous qualities so much in demand. 



146 chemistry and technology of paints 

Concrete or Portland Cement Paints 
Portland cement is an alkaline rock-like substance, 
which after it has set liberates lime. The literature is 
replete with statements that Portland cement floors 
cannot be painted, and it was not until 1903 that the 
first successful experiments were made for the painting 
of Portland cement. Prior to that time all sorts of 
things were recommended, such as strong acids like 
sulphuric acid and acetic acid, but it was soon found 
that the application of acids of this type to Portland 
cement destroyed the Portland cement because it dis- 
solved out the lime and left the sand and aggcegite 
loosely bound. 

Portland cement floors "dust" up under the abrasion 
of the heel, and until a successful method for painting 
them was found it was impossible to use them in an 
unco\'ered condition. In power houses where delicate 
electrical machinery was placed the contact points were 
ground out by the siHcious matter floating in the air 
through abrasion of concrete under the feet. The ac- 
companying photomicrographs show the appearance of 
a Portland cement floor highly magnified, and indicate 
in a general way the necessity for painting Portland 
cement. In warehouses, storerooms and office^ ^lerally, 
concrete floors had to be covered with liiKiici 
to prevent this continual dusting, which became 00 
The paints made of drying oils were readily 
and gave unsightly effects, and it was not until- J 
l)u!)licali<)n of a patent on this subject (U. S. IicU 
Patent \o. 813,841) that the trade in genera! began^ 
understand that a resin acid was necessary to combine » 
the lime and not destroy It. Previous attempts ha* \ 
been made de])ending upon the destruction of the lime, 



iflXED PAINTS 147 

but in this patent it was first shown that a chemical 
reaction took place and the lime instead of being de- 
stroyed was made to serve a useful purpose. A resinate 
of lime was formed when the coating applied had a 
sufficient acid number. 

The amount of free lime in concrete is not very 
great, for in a i : 3 mixture, that is, a mixture containing 
one part of cement and three parts of sand, the top sur- 
face varies in composition from 0.87 to 1,6 per cent of 
free lime. A large number 
of analyses were made by 
the author, and it became 
obvious that an acid num- 
ber of 5.0 is sufficient to 
more than neutralize the 
amoimt of lime present, 
and once neutralized dust- 
ing does not take place. 
It is well known that con- 
crete of any kind and of 
any mixture is rapidly 
disintegrated by paraffin 
or machinery oils and re- 
duced in time. If, how- 
ever, the cement filler or 
neutralizing liquid is composed of China wood oil and 
a haM resin like copal, the resulting calcium resinate 
becoims insoluble in oil, so that oil dripping on a 

«r of this kind does not disintegrate the Portland 
lent. Oil collecting on an unpainted concrete floor 
cause the floor to become as soft as cheese in time, 
I and then there ispo remedy for it excepting to take up the 
floor aA put-AJKA a new one. 'Hhere is no record that 
China vwd oil a^fcopal had ever been used on Portland 




No. 69. Photomicrograph of Portland 
cement floor composeti of 2 parts sand 
and I part cement. This Hoor is po- 
rous and will disintegrate rapidly unless 
properly treated with a cement floor 




148 



CBEMISTRY AND TBCBN0U3GT OF PAINTS 



cement floors prior to the apf^cation in question, and 
that this patent was new and useful is demonstrated by 
the fact that there are practically at this writing over 
forty Portland cement paints on Uie market, all o£ them 
based on the same theory. 

In 1910 it was suggested that zinc sulphate be used to 
overcome the pernicious action of the free lime in Port- 
land cement, and for a time this material had quite a 
vogue, but it has turned out that no man could tell how 
much zinc sulphate to use, for no man knew definitely the 
amount of free lime in any 
large area of Portland ce- 
ment, and therefore either 
too much or too little was 
used. If too little was used 
there was still some free 
lime left; if too much was 
used sulphate of zinc crys- 
tallized out, and when the 
wall or floor became wet, 
either through rain or 
through washing, the film 
of paint peeled off. 

Practically all the paints 
for Portland cement that 
arc on the market contain either China wood oil or a 
copal resin or both. Those composed of both of these 
materials have given the best satisfaction. Where ten 
years ago there was only one of these paints on the 
market today there are a large number, and it is 
estimated that more than a million gallons per year 
at this writing are used for the surface protection of 
Portland cement. 




Ko. 70. Highly magnified view of a 
fine crack in Portland cement con- 
struction — an example of incipient 

disintegration. 



mixed paints 149 

Paint Containing Portland Cement 

There is only one paint in existence thus far that 
contains a material equal to Portland cement, which 
is a tricalcium silicate and dicalcium aluminate, and 
which on setting liberates lime. This paint is known as 
"Tockolith," and it has been and still is very largely 
used among engineers for the protection of steel against 
corrosion. 

The author cannot go into this subject any more 
deeply because this discovery is his and he is interested 
in the manufacture of this material, and furthermore, 
this book is not the place to exploit a proprietary article; 
but inasmuch as this paint has been regarded by many 
engineers as at least a step toward the solution of ,the 
question of the protection of iron and steel, it is fitting 
that this brief mention of the material should be made. 

Damp-Resisting Paints 

Paints of this character are comparatively new, the 
first one having been manufactured by the author's firm 
and put on the market in 1892. It was made for the 
purpose of coating brine pipes and pieces of machinery 
which were continually under water. The original paints 
of this character were produced by melting a good grade 
of asphaltum and adding a suflScient quantity of gutta- 
percha together with a suitable solvent and a small per- 
centage of pigment. These paints served their purpose 
very well and were used very largely, but no matter how 
carefully compounded the gutta-percha separated from 
the asphalt base if the paints were allowed to stand for 
any length of time. 



I50 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Further experiments showed that cement mortar 
would adhere most firmly to such a paint. The paint 
could be applied even to a new brick wall, lathing 
and furring being omitted. It took such a long time, 
however, to introduce a paint of this character to the 
building public that the author's firm never thought it 
worth while to patent the application. 

Damp-resisting waterproof paints are now an adopted 
fixture in the paint industry, and while bitumen forms 
the base of paints of this character, treated China wood 
oil, and treated linseed oil in which glycerine is replaced 
with a suitable metallic base, should be added when 
making these paints. They are used widely and in 
various ways, having served their purpose so weU that 
engineers are beginning to adopt such paints as priming 
coats for metallic structures wherever cement or cement 
mortar is to be applied, so that oxidation by electrolytic 
action may be prevented. 

Enamel Paints 

Enamel paints in former years were pigments ground 
in varnish, which dried with a high gloss. Some people 
objected to this high gloss, and where a good grade of 
xarnish was used the film was rubbed with pumice stone 
and water until it produced an egg-shell finish. This 
then led to semi-gloss enamel paints, and finally we have 
the misnomer of having perfectly flat enamel paints 
today, for the very word ^* enamel" indicates gloss. 

For decorati\'e use the j^rincipal enamel paints are 
white, but it must l)e said at the outset of the chapter 
that this subject cannot be thoroughly treated in this 
book. It has become so vast that it would take a book 
of this size alone to do the subject justice. There are 



MIXED PAINTS 1 51 

\^st quantities of enamel paints made which are colored, 
but these are principally used for machinery of all kinds, 
for automobiles and for the so-called enamelling of various 
utensils, such as tool handles and the like. There are 
also vast quantities of black enamels made for technical 
purposes, and these are used for the manufacture of oil- 
cloth, patent leather and mechanical appliances. Those 
for oilcloth and patent leather are true oil enamels; 
those for mechanical appliances are principally made on 
an asphalt base. This chapter will treat of the subject 
of enamel paints for decorative purposes, which are 
principally white and mainly based on zinc oxid ground 
in a varnish or varnish oil. 

Prior to the mixed paint era white enamel was made 
by taking zinc oxid ground in either poppy oil or a 
bleached linseed oil, and thinning it with damar varnish 
as it was needed, and the painter did this himself. But 
as ready for use enamels were demanded improve- 
ments were made on this type of material. Today 
the three types of white enamels are: 

First. The zinc oxid types ground in damar varnish. 

Second. The lithopone types ground in China wood 
oil and rosin varnishes. 

Third. The zinc oxid types ground in stand oil only.^ 

The damar tj^je first mentioned is simple to make, but 
produces an enamel which does not flow out, which sets 
very quickly and which sometimes settles hard in the 
package and sometimes does not, depending entirely upon 
the gum damar used for the purpose. There are a great 
many varieties of gum damar whose acid figure ranges 
from 8. to 26., but the acid of gum damar is very weak 
as compared to the acid of the majority of copals, and 

* Stand oil has been described on page 176 in the chapter on 
Linseed Oil. 



152 CHEMISTRY AND TECHNOLOGY OF PAINTS 

does not readily unite with a base like zinc; therefore 
a damar type enamel remains in suspension for several 
years. For enamel purposes damar varnish is usually cut 
cold, that is to say, six pounds are dissolved in a gallon 
of solvent in an ordinary vessel at room temperature; 
the resulting varnish is always cloudy, due to occluded 
water in the damar. To remove the latter the cold-cut 
damar is placed in a steam-jacketed kettle and heated to 
about 220° with steam under pressure. Steam at atmos- 
pheric pressure has a temperature of 212*^ F., so that at 
least ten pounds pressure is necessary in a steam-jacketed 
kettle to drive oflF the moisture contained in damar; but 
when this is done the damar darkens unless the operation 
is carried out in an aluminum or silver-plated kettle. 
Such solvents like cymene, toluol and xylol are added 
up to 5 per cent to damar varnish to overcome the 
cloudiness with fairly good results, but the action is not 
immediate, and the damar must be tanked for a con- 
siderable time. 

The second type, or lithopone and China wood oil- 
rosin varnishes, are very good for household use, but not 
so good for painting furniture, unless the varnish is 
made by an expert varnish maker with a minimum amount 
of rosin and the maximum amount of China wood oil, 
otherwise varnish of this type becomes hygroscopic in 
damp weather or sticky in hot weather. White pigments 
other than lithopone are not recommended for enamels 
of this t}Tpe because of the high acid figure of the varnish. 

The third type, in which stand oil or linseed oil and 
zinc oxid are used alone, is the popular type of today, 
but has the disadvantage of drying slowly, yet this type 
of enamel will last for many years, and stands exposure 
even in the American climate for about eighteen months. 
It is made as follows: 



MIXED PAINTS 153 

Ten pounds of zinc oxid are ground in ordinary raw 
linseed oil, and this paste after having been finely ground 
two or three times is mixed with one gallon of stand oil, 
and then a gallon or less of turpentine or a mixture of 
turpentine and turpentine substitute is added. When 
made in this manner it takes iio*^ F. of heat four or five 
hours to dry it so that it is free from tack. 

Another method is to grind ten pounds of zinc oxid in 
japan drier, which may be a drier made of resinate of 
manganese and lead, and then add ten pounds of this 
paste to one gallon of stand oil. This will air-dry in five 
hours, and while it gives good results for interior pur- 
poses it is not recommended for exterior use. 

A third method of making these enamels is to grind 
the zinc oxid together with the stand oil in a roller mill, 
and then reduce with the necessary quantity of diluent 
and drier and strain very carefully. 

All enamels made along these lines have a tendency 
to turn yellow in the dark. Some, in fact, turn exceed- 
ingly yellow — almost the color of beeswax — depending 
upon the amount of chlorophyll or green coloring matter 
in the original linseed oil, and no method has yet been 
devised whereby this can be prevented. Many experi- 
ments have been made by the author tending toward 
improving this with partially good results, such as, for 
instance, the addition of an oxidizing material like 
hypochlorite of lime to the enamel. 

From the foregoing it is clearly evident that enamel 
paints may be nothing more or less than pigments ground 
in boiled linseed oil without the addition of any resin or 
gum, and the effect produced is that of high gloss and 
flexibility. 



i 



CHEMtSTRV AXD TEC/INOLOCV OF PAINTS 



Flat Wall Paints 

Flat wall paints have come into existence ia. 
United States, and it is estimated that hundreds of % 
sands of gallons are now made yearly, and that 
give excellent results. Most flat wall paints c(^ 
lithopone as a pigment, the photogenic quality of ij 
does not play a great r61e in interior painting. H 
of the flat wall paints contain as high as 20 per cdl 
water in the form of an emulsion, as is the case when 
water is admissible in mixed paints; for in England 
flat wall paints which are sold under a different 
either in paste form or ready for use, are all white 
containing a small percentage of Unseed oil, and are 
reverse practicaUy of the American tj^pe of paints. 1 
are called washable in England when they are wsj 
from the bottom up, for when they are washed froq 
top down and the water streaks the wall there is dd 
of dissolving some of the paint and producing a bad 
whereas the American types of wall paints, even 
that contain 20 per cent of water, withstand the 
of washing either from the top down or from the 
up. There are, of course, many types which 
no water, the principal vehicle for this tj-pe of 
being a semi-fossfl damar mixed with linseed oil or J 
generally a rosin-China wood oil varnish containing^ 
50 per cent of solvent. * 

Many of the failures of the flat wall pamts 4 
peel and disintegrate are due to the sizing on which 
are painted. Glue, shellac or cheap varnish sizing 
generally worthless on plastered walls, while an oil)^ 
acid X-Ypc of filler gives results which are permanea 



mixed paints 155 

Floor Paints 

Wooden floors are painted as a rule with a varnish 
paint which dries hard over night and produces a wear- 
resisting waterproof surface. In composition, paints for 
wooden floors are analogous to paints for concrete floors, 
and are composed of a minimum amount of oil which 
dries by oxidation and a maximum amount of hard resin 
varnish. The rosin varnishes, particularly those of the 
China wood oil type, do not wear as well as the hard 
resin varnishes. 

The pigments used in floor paints do not play a great 
role. Numerous experiments made show, for instance, 
that zinc oxid is not a useful pigment for the reason that 
the acid number of a floor paint varnish is sufficiently 
high to combine with the zinc and form an unstable paint 
— one which thickens up in the container and becomes 
unfit for use in a few months. Therefore lithopone is 
found very useful, and the inert pigments are preferred 
also for this reason. 

Shingle Stain and Shingle Paint 

Shingle stain is not to be confounded with shingle 
paint. A stain for shingles is translucent; a paint for 
shingles is opaque, and the difference between the two 
is quite marked. One shows the grain of the wood, and 
the other gives a painted effect and does not show thfe 
grain. There is hardly any difference between shingle 
paint and the average ordinary mixed paint, with the 
exception that some manufacturers add asbestine in 
order to give it some fire-resisting quality. On this point 
it is well to mention that shingles that are painted, par- 
ticularly with a paint that has a fire-resisting quality, 



156 CHEMISTRY AND TECHNOLOGY OF PAINTS 

are superior to those coated with shingle stain, even 
though they may not look as artistic, because sparks 
flying from a chimney on a roof that has been stained 
and has thoroughly dried out are very likely to ignite 
the roof. 

Shingle stain is generally made from the very brilliant 
pigments and crude creosote. These pigments are as a 
rule ground in linseed oil, and two pounds are generally 
added to a gallon of creosote. Ordinary creosote oil is 
used for this purpose, probably because it has some wood 
preservative quality. Other manufacturers use ordinary 
kerosene and take two pounds of the strongest colors in 
oil that they can get. Still other manufacturers use 
crude carbolic acid or crude cresol and kerosene, but 
in spite of all these treatments shingles rot just the same. 
It is the soft pastel effect which a shingle stain gives that 
commends it so highly; but the same pastel effect is 
produced with shingle paint after the lapse of a year 
or two, provided a good paint is properly reduced with 
about 50 per cent of volatile solvent. 

On new work shingles are generally dipped. A bundle 
is taken and dipped into a barrel and allowed to soak 
so that the wood will absorb all that it can. On old 
work, of course, it must be applied with a brush. 

Asbestine is frequently added in the proportion of 
one pound to the gallon of shingle stain containing heavy 
colors to prevent them from settling. One of the most 
difficult shingle stains or shingle paints to produce is a 
permanent red. For this purpose the oxids of iron 
(FcoOs) are used, but wherever oxid of iron is exposed to 
the sunlight in the presence of linseed oil or other organic 
oils it probably changes to a ferroso-ferric condition, 
becomes considerably darker and is converted into a 
brown. This is less noticeable in a shingle stain than it 



MIXED PAINTS 157 

is in a shingle paint, because the shingle stain is largely 
composed of a volatile solvent, and the small amount of 
binder has relatively a lesser action than the binder in 
the shingle paint. It has been suggested, and there is 
probably some value to the suggestion, that potassium 
dichromate to the extent of one ounce to the gallon 
should be ground in crystalline form with the paint 
in order to prevent any reduction. Hypochlorite of 
lime has also been suggested, and of the two the 
hj-pochlorite would be the better as long as it would last, 
because it would not wash out and be likely to stain the 
building. Dichromate would be very likely if it ran over 
the gutters or leaders to produce a bad stain. 



CHAPTER XII 

Linseed Oil 

This oil is still the principal oil used in the manu- 
facture of paints, and mthin the last ten years ver>^ 
extensive work has been done on the constants and 
specifications for linseed oils generally, as will be noted 
from the reports of the American Society for Testing 
Materials and several other reports quoted by the author. 

The raw linseed oil produced in the United States 
comes principally from the northwest. The foreign oils 
come from Calcutta, the Baltic, and the Argentine 
regions. There is considerable difference between these 
oils, the Baltic being perhaps the best and very highly 
prized by varnish makers. 

The constants of linseed oil show very wide variations; 
for instance, its specific gravity will run from 0.931 to 
0.935. Its iodine value will var>' from 160 to 195 or 
more, while the saponification value will run between 
190 and 196. The greatest differences are found in 
North American linseed oil, the figures being sometimes 
so perplexing that it is difficult to reconcile them wath 
the standards of Baltic oil. These discrepancies are 
easily traceable to the natural impurities found in Ameri- 
can linseed oil, as, for instance, oils from weeds growing 
in the flax fields. American linseed oil is likewise 
inclined to show the presence of water to a greater 
extent than fore'gn oils, but this, however, is a question 
of age. If raw linseed oil is allowed to settle until it 
becomes perfectly clear and shows no sediment or tur- 



LINSEED OIL 159 

bidity at 0° C, it cannot be said to contain water. 
The question here naturally arises as to the use of the 
term "pure." Calcutta and the Baltic seed are freer 
from foreign seeds than the American product, and 
although the amount of foreign seeds which appear as 
weeds in the field is very small, their presence alters the 
chemical and physical characteristics of the American 
oil. Taking Baltic as a standard, it could be reasonably 
argued that American linseed oil is adulterated, yet no 
man would have a moral or legal right to condemn 
American linseed oil because it differed from the Baltic. 
On the other hand both climate and soil have a well- 
knowTi influence on vegetation; even the percentage 
of oil derived from a given seed cannot be said to be 
constant. It is also stated that virgin soil produces 
better seed than a replanted field and this statement 
appears reasonable. 

To how great an extent the natural or negligible 
admixture of the oil from foreign seeds to linseed oil 
affects the wearing quality of the oil, it is impossible to 
say, but it must be admitted that an oil containing up 
to 3 or 4 per cent of the oil of foreign seeds or weeds 
will not act as well in the kettle for varnish or boiling 
purposes as a purer oil. Taking these facts into con- 
sideration, a chemist must beware of giving an opinion 
as to the quality of linseed oil, and where there ;s no 
evidence either chemical or otherwise that the oil has 
been intentionally diluted with other materials no 
adverse opinion should be forthcoming. If the exam- 
ination of linseed oil shows an appreciable percentage 
of paraflSn oil, it can be positively inferred that no 
weed growth had anything to do with this adulterant 
and the mixture must be regarded as intentional or 
accidental. 



i6o CHEMISTRY AND TECHNOLOGY OF PAINTS 

Raw linseed oil is extracted from the seed by the 
old-fashioned method of grinding the seed, heating it, 
placing it between plates and then pressing it until the 
remaining cake contains the least possible quantity of 
oil. The newer method is a continuous process by which 
the seed is ground and forced in screw fashion through a 
tube, the oil oozing slowly through an opening in the 
bottom of the tube and the cake falling out at the end 
in flakes. When the seed is fed in this manner without 
heating, a better quality of oil results. The third 
method consists in crushing the seed and extracting the 
oil by means of naphtha. The resulting liquid is evapo- 
rated, the naphtha recovered and the oil sold for painting 
purposes. It appeared, however, that this process, while 
very profitable for the manufacturer, was not profit- 
able for the consumer, and although it made a veiy 
fair paint oil, it was found that for the purpose of coating 
leather, oilcloth, and window shades, the oil had the 
unfortunate faculty of soaking through the fabric, and 
when a piece of goods was rolled up too soon and 
allowed to stand for the greater part of the year it 
was almost impossible at the end of that time to unroll 
the goods, the whole having become a solid mass. Inves- 
tigation showed that some of the proteids in soluble 
form were extracted by the naphtha. This was called 
''new process oil,'' and it was generally understood that 
cake made from new process oil was not as good cattle 
feed as cake made in the old-fashioned way, probably on 
account of the removal of part of the proteids. 

If linseed oil were uniform, both as to source and 
nature of seed, a chemical formula could be established 
for it, but because it is not uniform the acids cannot 
be given in quantitative relation. Linseed oil should 
give no test for nitrogen; if it does, the proteids in the 



LINSEED OIL i6l 

seeds have been attacked. Probably 95 per cent of all 
the linseed oil made is sold in the raw state, and, strange 
to say, probably 95 per cent or over of all the linseed 
oil used is consumed in any other but the raw state. It 
must not be inferred that all paint manufacturers 
manipulate or treat their linseed oil by heat and other 
methods of oxidation, for, while many of them claim to 
do so, not one that the author is acquainted with could 
afford to handle and manipulate linseed oil. At the same 
time, raw linseed oil cannot be used for the purpose of 
making paints unless a drier be added, and from the 
very moment that the drier, either in the nature of a 
siccative oil, resin, or Japan, is mixed with the oil, the 
chemical constants of the oil are altered. The change is 
an irreversible reaction. As an example, it may be cited 
that if 90 per cent of linseed oil be mixed with 10 per 
cent of volatile constituents and Japan driers, the chemist 
cannot separate the three substances and produce three 
vials containing raw linseed oil in the state in which it was 
used, and the drier in an unaltered condition. The volatile 
solvent, if it be benzine, is the only one of the three that 
can be recovered in any approach to its original condition. 

The literature on raw linseed oil is very incomplete, 
and more attention should be paid by chemical experts 
and writers to the subject of identification of linseed 
oil as it really exists in the paint. 

In the chapter on the "Analysis of Oils" it will be 
seen that when the iodine number of an oil is 180 the 
same oil when extracted from mixed paint may show no 
and still be absolutely pure, for the reason that the 
metallic salts which have been added to the oil in the 
form of Japan or other siccatives have in a measure 
saturated some of the bonds of the linseed oil, so that 
less iodine or bromine is absorbed. 



l62 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Linseed oil dries by oxidation, and this oxidatioii is 
hastened by the addition of bases or salts of lead and 
manganese. There is no doubt that some of these act 
catalytically, and there is likewise no question that some 
of these driers continue to act long after the oil is phys- 
ically dry. In drying, raw linseed oil is supposed to 
absorb as much as i8 per cent of oxygen, but in actual 
practice where solid linseed oil is used as an article of 
commerce it seldom absorbs more than lo per cent of 
its original weight. The addition of a drier has much to 
do with the life of a paint, there being no two driers 
that act exactly alike. If it is the intention of the paint 
manufacturer to make a paint that will last the Jongest, 
he must study the chemical and physical characteristics 
of the drier which he uses. Red lead (PbjOO added to 
linseed oil at a temperature up to 500° F., will make a 
very hard drying film which in time becomes exceedingly 
brittle. This can be very easily demonstrated if the red 
lead oil be coated on cloth and its effect closely watched. 
On the other hand, the addition of litharge to linseed oil 
produces the opposite effect, and an exceedingly elastic 
film is produced. The various manganese salts all act 
differently and are frequently used to excess. Manganese 
starts the drying operation, the lead salts continue it, and 
the manganese again hastens the end. Borate of man- 
ganese is, perhaps, the least objectionable of all man- 
ganese salts, but the black oxid or peroxid is most 
largely used, and if not used in excess is an exceedingly 
valuable assistant in the dr>ang of linseed oil. 

These driers are usually prepared by adding the oxids 
of lead and manganese to melted rosin. After a resinate 
of lead and manganese is produced, a small quantity of 
linseed oil is added and the mixture then cooled either 
with turpentine or benzine or both. There are hundreds 



LINSEED OIL 163 

of varieties of the so-called Japan driers, the best ones 
containing the minimum amount of rosin and a certain 
percentage of the dust of Kauri gum. The oil driers 
are made in a similar way, excepting that no rosin is 
used, and these driers do the least harm. Lime is very 
frequently used in addition to oil, sometimes in con- 
junction with rosin and sometimes alone, in order to 
produce a drjdng effect. The so-called lime oil will dry 
with a hard and brittle film. The salts of lead and man- 
ganese are not as good for mixed paint purposes as they 
are for technical purposes. The chloride of manganese 
when added to linseed oil reacts upon it, and in the 
presence of any moisture in the oil will liberate traces of 
hydrochloric acid. Sulphate of manganese and lead 
acetate will act similarly, and wherever there is a trace of 
liberated acid in paints their rapid and uniform dr>'ing 
is interfered with. Zinc sulphate and lead sulphate are 
also excellent driers. It is considered good practice to add 
a small amount of calcium carbonate wherever these 
driers are used in order to neutralize the acidity, and 
when this is done no ill effect can be observed. Prob- 
ably the most flexible drier is Prussian blue, which is 
soluble in linseed oil at 500° F., and produces such a 
flexible film that the patent leather industrj- is based 
upon it. 

Some twenty-three years ago the author manufactured 
a new drier which is an improvement on Prussian blue. 
Briefly described, this drier is made out of a by-product 
Prussian blue which is treated with an alkali in the 
presence of calcium oxid and water. A brown powder is 
the result, which has no uniformity of color but has 
given excellent results as a drier. This brown has been 
erroneously called "Japanners Prussian Brown," or 
Japanese brown. It is soluble in linseed oil at 500° F., 



ICH CHEXtlSTRV AND TECHNOLOGY OF PAINTS 

ami produces a film which is neither too hard nor too 
s*.^ft. but remarkably elastic and admirably adapted for 
m;iking certain paints and varnishes. It cannot, how- 
ever, be said to replace any of the good linseed oil driers 
for mixed {xiints, where too flexible a paint is not desir- 
able, jxirticularly on steel work or exterior work, as 
bUster> are likely to result from the difference in expan- 
5iioa. Howex^er. as a base for the manufacture of enamel 
vantishes and oils this drier has proved itself admirably 
adapt^xt. 

tiiisiwt oil IS a glyceride of several fatty acids, and 
tcwkowit^i^h h;is pRwed that water wall replace the 
glywridc radical and hydrolize the oil. (See "New Paint 
^'ouvlitions Kxisting in the New York Subway" by 
\Li\iituUau l\Kh, Journal of the Society of Chemical 
liulustrw No. lo, VoL XXIV.) 

The action between a fat and a caustic alkali in boil- 
it\i: soluttvMU by which a soap is formed and glycerin set 
trvv\ IS tvv well known to need further discussion. The 
'aVs\ .uivls which are amibined with the soda can be 
■ilv:\i:ov'. l>v the addition of almost anv mineral acid to 
fae sv\r.v rru> >vr^K>nirication can be produced by the 
a.i v^tv V •. u.itvT aloue on raw linseed oil. WTiere a paint 
V v>v.tai:i> I;:r,o .^r U\ui this hydnilysis probably is hastened. 

We iia\c hcriL^ an excellent explanation of the so- 
ealled ih^:\>us w.Usilities. or non-waterproof qualities, of 
linseed vnl as a :\uut» which is further brought out by 
I he uut that \\b.e:\ lius^vd oil is treated with Prussian 
hUie vM laparuaers rrussian brown it cannot be hvdrolized 
In nteaus oi water» for the acid radical has formed a com- 
pK^ie V oinpvHitid with the iron in lx>th of these driers, and 
the prv^lvM\gal heaiini: has volatilized the glycerin. Con- 
Mviuentlw when a paint is made by the treatment of 
lin>eed vmI at a temjxTature of over 500° F., with a 



> 



* ■ 



LINSEED OIL 



165 



neutral and soluble base like the ferri-ferro cyanide of iron, 
the resulting film is not linseed oil nor a linoleate of any 
base with free glycerin, but a complex compound com- 
posed of the various linseed oil acids united with iron. 
This gives us the basis of waterproof paints. This is 
ex-ident from the quality of patent leather, which is not 
only much more flexible than any paint made in the 
ordinary way, but is likewise waterproof. 

The following are the probable formulas for linseed 
oil in its various stages: 



CsHfi 

Pb 

Mn 

Mn 
Pb 

Fe 



C16H26O2 1 

C16H28O2 • Raw linseed oil. 

C18H32O2. 

CieHaOz+On 

CieH2802 + On r Japan and linseed oil. 

CisHaOz-hOnJ 

rCieH2602-hO„ 
C,eH2802-hO„ 
. CisHajOz -h On . 

Ci6H2602+On 
CieH2«02-hOn 
.Ci8H8202-hOn. 



Boiled or varnish oil. 



Waterproof oil. 



There are questions in regard to the physical and 
chemical characteristics of linseed oil on which there has 
been considerable discussion and naturally a difference 
of opinion. The first is whether linseed oil dries in a 
porous film, and the second is whether linseed oil while 
drying goes through a breathing process during which 
it absorbs oxygen and gives off carbonic acid and water. 
With reference to the porosity of the dry film of linseed 
oil, the following extract is made from the Journal of 
the Society of Chemical Industry (May 31, 1905, "New 
Paint Conditions Existing in the New York Subway'' 
by Maximilian Toch). 



l66 CHEAflSTRY AND TECHNOLOGY OF PAINTS 

"In a paper before the American Chemical Society 
on March 20, 1903, I gave it as my opinion that a dried 
film of linseed oil is not porous, excepting for the air 
bubbles which may be bedded in it, but that any dried 
film of linseed oil subjected to moisture forms with it a 
semi-solid solution, and the moisture is carried through 
the oil to the surface of the metal. We then have 
two materials which beyond a doubt have sufficient 
inherent defects to produce oxidation under the proper 
conditions, and granted that the percentage of carbon 
dioxid in the air of the tunnel is not beyond the normal, 
the fact that carbon dioxid together with moisture would 
cause this progressive oxidation is sufficient warrant for 
the discontinuance of paints that are not moisture and 
gas proof. Dr. Lewkowitsch demonstrated in his Canton 
lectures that the fats and fatty oils hydrolized with 
water alone, and linseed oil is hydrolized to a remarkable 
degree in eight hours when subjected to steam. It can, 
therefore, be inferred that water will act on linseed oil 
without the presence of an alkali, and that calcium added 
to water simply hastens the hydrolysis by acting as a 
catalyser. This, then, bears out my previous assertion 
that a film of linseed oil (linoxyn) and water combine to 
form a semi-solid solution similar in every respect to 
soap, and inasmuch as we have lime, lead, iron and 
similar bases present in many paints, it is almost beyond 
question that these materials aid in the saponification 
of oil and water/' 

If a drop of linseed oil is spread on a glass slide and 
one half of it covered with a cover glass, it will be readily 
seen under the microscope that the dried film is as solid 
as the glass itself, that there are no pores nor any 
semblance to a reticulated structure visible in the oil, 
and the author therefore makes the statement with 




45- 1* 13 a glass flask of about a litres capacity. Through the lube A 3.4 grams of refined 
seed oil, which had been heated lo 400 degrees E. for one hour, were introduced and well 
itributed over the inner surface of ihe fiask. Dry oxygen free from COi was blown through 
i flask, by means of tubes A and C, until the flask contained pure oxygen. The lube A was 
;n sealed, as shown in sketch, mercury brought uji into Ibc manomelcr by elevating B lo ihe 
■sition shown. The flask was ihen filled with oxygen at atmospheric pressure and effectually 
kicd. As drying proceeded atid oxygen was absorbed, the diminished pressure was reaiJ off 

the manometer. When this became constant the funnel which was connected to A by a rubber 
be was filled with filtered Barium Hydrate solution, and (he point at A broken, allowing this 

run into the flask without admission of air. In a few minutes Barium Carbonate was formed, 
owing condusivcly that ujme CC^ had been generated by the oil. 
167 



1 68 CHEMISTRY AND TECHNOLOGY OF PAINTS 

absolute certainty that linseed oil dries with a homo- 
geneous film in all respects similar to a sheet of gelatin 
or glue. 

The question as to whether linseed oil goes through a 
breathing process, absorbing oxygen and liberating car- 
bon dioxid and water, is one of great importance and 
one which the author has worked out very carefully with 
positive results. In the illustration a piece of filter paper 
two inches in diameter was dipped in linseed oil of known 
purity and suspended in a flask in air absolutely free 
from CO2 and water. Investigators have always com- 
plained of the inability to obtain tight joints in an 
experiment of this kind, and in order to be certain that 
there was no leakage all joints were covered with 
mercury after having been first shellacked. The mano- 
meter gave a curve which indicated the drying, a 
thermostat being a part of this instrument, so that 
absolutely uniform conditions were obtained. At the 
end of thirty days the drying curve was obtained, and 
when the baryta water was led into the bottom of the 
flask there was hardly a trace of turbidity to be noted. 
This experiment was repeated many times, always with 
the same result, and the amount of water or moisture 
obtained could not be weighed. It was therefore reason- 
able to conclude that the linseed oil gave off neither CO2 
nor water, but had absorbed oxygen. 

The author, however, concluded that this experiment 
was entirely too delicate, inasmuch as only one gram of 
linseed oil was absorbed by the paper. Therefore, an 
apparatus was devised as shown in the illustration, 
without joints and so absolutely air-tight that the ques- 
tion of leakage could not arise. The flask was filled with 
linseed oil and then emptied by replacing the oil by air 
free from water and CO2, the inside and bottom of the 



LINSEED OIL 169 

flask being left heavily coated with linseed oil which had 
been previously heated to 400° F., for one hour. The 
manometer tube formed a part of this apparatus, and 
when the oil had dried completely (which was manifest 
by its wrinkled and bleached appearance and likewise 
by the manometer indication) a rubber tube was attached 
to the point E, a funnel inserted, and a filtered solution 
of barium hydrate was allowed to run in as soon as the 
tip E was broken. After ninety seconds the solution of 
barium hydrate turned milky, showing conclusively that 
CO2 had been generated in the drying of linseed oil. 

The next experiments were made quantitatively, and 
while the amount of moisture could not be accurately 
measured, the amount of carbon dioxid was in no case 
higher than A of i per cent, whereas the absorption 
of oxygen was 19 per cent. It must therefore be admitted 
that linseed oil does give off CO2, but the quantity is 
relatively so small that it is a question whether it should 
be taken into account at all. 

It is now a known fact that carbon dioxid acts as a 
rust-producer on iron or steel, and if linseed oil gave off 
any appreciable quantities of CO2 and water they would 
act as rust-producers in themselves rather than pro- 
tectors; and while it may be possible that some linseed 
oils give off more of these two substances than others, 
the amount under normal conditions cannot be very 
great, as these experiments show. 

Refined or bleached linseed oil is used to a very great 
extent for the manufacture of white paints. The methods 
employed for bleaching linseed oil have not undergone 
very much change until lately. The coloring matter in 
linseed oil is largely chlorophyll, the bleaching of linseed 
oil depending not on the extraction of this chlorophyll 
but on its change into xantophyll, which is yellow. 




IS WL'iijliril, ihc filliT {Ki)x:r Wiis suijiL'nikil in the Krlcnmi'viT iiitsk, on 
lliu trntlntii of which was a siiluLionoC Barium lly<lraie((rrefn>m CUj) toabsurl) 
ihc Ci'h formtil l>y iIil- <lr«'ini; uf the oil. The flask was immvrsFd in a wuIit- 
thcmiiislat, the watiT of whiih was slimil In- a revolving mcchaniral slim-r. 
A ihiTmii-regulalcir.by means uf which the gos-tlamc unik-r the thermostat was 
auKinialii'iilly nt;utatc<I, wus placed under the llisk. By D]x-ning the glass- 
cock, u.lyi^'n was ailmitlcd frmn time to (iitic to (he Krli.-nm<'y<-r flusk, and the 
alisiiqitiiin cit iixygi'n was irail on Ihc mcrcvir>--Tn:inc)nii>liT. The readings were 
alwai-s marie al the same Irmjieralure. The rjxvRen, before entering the Krlen- 
mivi-r flask, w:is [i^issifi Ihr.iuRh the KOEI dulh'. where it was wash.-d free fn.TU 
C<).. This exiM-rimem was omcliirlea in iripUrate with girat care, the joinis 
hcLnK all sealed with shellac and placeil iin.l.T iiuT.iiry. No Cf >, or H;0 beyond 
a trace could Im- detemiincd, owing to the small iiuanlity of linseed oil which the 
filter ))a[ier contained. 



LINSEED OIL 171 

Sometimes linseed oil will have a reddish cast instead 
of the. usual greenish cast. This color is attributed - to 
another form of organic matter known as ery^throphyll. 
These three tints, the green, yellow, and red, are analogous 
to the tints in autumn leaves. 

. All methods for extracting chlorophyll from linseed oil 
have proved extremely difficult and expensive. The ac- 
cepted method, therefore, has consisted in the treatment of 
linseed oil with an acid in order to convert the green coloring 
matter into the yellow. This is probably the reason why 
no linseed oil exists which is water white, although the 
author has made several samples which are almost color- 
less, but when compared in a four-ounce vial with chemi- 
cally pure glycerin it can readily be noted how far from 
colorless the so-called bleached linseed oil is. The method 
employed for bleaching linseed oil consists in the addition 
of sulphuric acid and the blowing of air into the oil at 
the same time. The oil becomes cloudy and develops 
small black clots. When this cloudiness is allowed to 
settle out, or the oil is filtered through a filter press, it 
is very much paler in color, and is then known as refined 
or bleached linseed oil. 

Simlight has a similar effect, the oil produced by 
bleaching with light and age being superior in quality 
to the sulphuric acid oil. In the sulphuric acid treat- 
ment the oil, the water, and "foots," together with an 
appreciable amount of emulsified oil, settle to the bottom 
of the tank. These are drawn off, and are of some value 
for making cheap barn paints by mixing with lime and 
the oxids of iron. In another method, which produces a 
still better bleached oil, chromic acid is used. If a 
solution of this acid, which is blood red, be added to 
linseed oil, and the mixture agitated, a ver>' much paler 
and more brilliant oil is obtained, but it is rather 



172 CHEMISTRY AND TECHNOLOGY OP PAINTS 

expensive to produce. The treatment by means of an 
electric current in the presence of moisture is likewise 
used to some extent, but it appears that this method is 
far more suited to other oils. Great secrecy is main- 
tained among those who have a knowledge on this 
subject. Peroxid of hydrogen has likewise been recom- 
mended, but from the standpoint of cost the sulphuric 
acid method is still the one that is used to the greatest 
extent. 

The new methods which are favorably spoken of, and 
which the author has found to be inexpensive and 
efficient, involve the use of the peroxids of calcium, 
magnesium, and zinc. These peroxids are made mto 
paste with water, one pound being sufficient for 200 
gallons of linseed oil. This amount of oil is placed in 
an open kettle or vat, together with the peroxid, and 
thoroughly agitated. During agitation a strong solution 
of sulphuric acid is added, which liberates nascent oxygen. 
If the oil be allowed to settle, or is filtered, and is then 
heated to drive oflf any traces of moisture, a very brilliant 
pale oil is obtained. 

It has always been understood that linseed oil con- 
tained albuminous matter which coagulated at a tern- 
perature of 400° F., or over, and produced a flocculent 
mass. When an oil answered this reaction it was said 
to "break" at the low temperature and was useless for 
making varnish oil and other high grades of linseed oil. 
G. W. Thompson found that this break was not due 
to the presence of albuminous and nitrogenous matter, 
but that it was caused by the separation of several 
phosphates. This explanation has generally been ac- 
cepted as correct. If an oil, therefore, is allowed to age, 
the phosphates settle out and the oil does not break. 
Cold-pressed linseed oil, if it breaks at all, does not break 



LINSEED OIL 173 

at as low a temperature as hot-pressed oil. Bleached 
linseed oil does not wear as well as the oil that has been 
clarified by standing. 

The demand for brilliant white paints or brilliant 
enamels is responsible for the manufacture of the so- 
called water-white oils. From a large variety of tests 
made by the author it was fully demonstrated that 
white paints composed of mixtures of pigments such 
as sublimed lead, zinc oxid, and white lead all showed 
absolutely the same whiteness within two weeks after 
they were exposed to the light, irrespective of the 
kind of raw linseed oil used. One of the five tests 
w^as made with a paint prepared with a linseed oil that 
had not been aged for more than two months, but 
within the time mentioned it was just as white as the 
rest. 

Linseed oil paints are supposed to deteriorate after 
a few years and lose their value, owing to the decomposi- 
tion of linseed oil. This statement is questionable, and 
while there is no doubt that the ready-mixed paint 
thickens and changes slightly in its chemical and physical 
characteristics, the change is exceedingly small in a con- 
tainer which is hermetically sealed. There is no doubt 
in regard to the reaction which takes place between the 
oil and white lead, zinc oxid, and a number of the 
unstable compounds in a mixed paint. While these 
reactions are very slow, they are at the same time very 
definite. If the value of a paint were reduced to a 
curv^e it would probably be found that the curve would 
be represented by the arc of a large circle approaching 
a straight line. As far as paste paints are concerned, 
particularly white lead, all painters prize white lead more 
highly when it is old than when it is fresh. 



1-4 k:h£mistry and technology of paints 

typical Analysis of Bleached, Refined Linseed Oil 

S^Hxntk Gravity 932-.934 

Kniine Value (Hanus) Above i8o 

Sa(x>nification Value 190-194 

Acid Value 3-5 

Standard Specifications, American Society for .Testing 

Materials, 19 14, p. 335 

Purity of Raw Linseed Oil from North American Seed 

Properties and Tests 

I. Raw linseed oil from North American seed shall conform to 
the following requirements: 

Max. Min. 

Sp. gr. ^^*^o C 0.936 0.932 

15-5 

** or — ^ C 0.931 0.927 

25 
Acid Number 6.00 

Saponification Number 195. 189. 

Unsaponifiable — per cent 1.50 

Refractive Index at 25° C 1.4805 1.4790 

Iodine No. (Hanus) 178. 

A linseed oil may however be pure if the iodine num- 
ber is 165 and it may be just as pure if the iodine num- 
ber is i()5. The latter number was prevalent in the crop 

SrwDAKi) Spkcifications for Boiled Linseed Oil from 

North American Seed^ 

Properties and Tests 

I. HoiliMl linseed oil from North American seed shall conform 
til I 111" lollowing requirements: 



I 



Aiiuriean Society for Testing Materials, 191 5, p. 420. 



UNSEED OIL 



175 
Max. Min. 



Specific Gravity — - - C o-945 o-937 

15-5 

Acid Number 8. 

Saponification Number 195. 189. 

Unsai)onifiable Matter, per cent 1.5 

Refractive Index at 25° C 1.484 1.479 

Iodine Number (Hanus) 178. 

Ash, per cent 0.7 0.2 

Manganese, i)er cent ... 0.03 

Calcium, per cent 0.3 

Lead, per cent o.i 



Navy Department Specifications 

Boiled Llnsekd Oil 

Composition 

1. Boiled linseed oil shall be absolutely pure boiled oil of high 
grade, made wholly by heating pure linseed oil to over 350° F. with 
o.xids of lead and manganese for a sufficient length of time to secure 
proper combination of the constituents and !)e proi>erly clarified by 
settling or other suitable treatment. Evidence of the presence of any 
matter not resulting solely from the combination of the linseed oil 
with the oxids of lead and manganese will be considered grounds for 
rejection. 

Chemiral Constants 

2. The oil shall upon examination show: 

Unsaponifiable matter Not more than 1.5 per cent. 

Lead oxid (PbO) Not less than 0.20 per cent. 

Manganese oxid (MnO) . . . .Not less than 0.04 per cent. 

Io<line No. (Hanus) Not less than 17S. 

Specific gravity at 60° F . . . Not less than 0.938. 

The oil shall give no appreciable loss at 212° F. in a current of 
hydrogen. 

Phvsical Characteristic 

3. When flowed on glass and held in a vertical position, the oil 
shall dr\' practically free from tackiness in 12 hours at a temperature 
of 70^ F. 



176 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Basis of Purchase 

4. To be purchased by the commercial gallon; to be inspected 
by weight, and the number of gallons to be determined at the rate of 
7^ pounds of oil to the gallon. 

Quantity f How Determined 

5. The quantity of oil delivered in 5-gallon shipping cans will be 
determined by taking the gross weight of 10 per cent of the total 
number of cans, selected at random, from which the average gross 
weight of the delivery will be determined. A sufficient number of 
these cans will be emptied to determine the average tare, and the net 
weight of the oil will be taken from the figures thus obtained. 

Stand Oil 

Stand oil is a very heavy, viscous form of linseed oil 
which has great use in the arts for the manufacture of 
both air drying and baking enamels. It is supposed that 
it originated in Holland, but there is a difference of 
opinion on this for the reason that the table oilcloth 
manufacturers in Scotland made a similar oil under the 
name of ^'marble oir^ long before the Dutch made any 
enamel paints. 

The method of making marble oil, which is a form 
of stand oil, is simply to heat a linseed oil which has 
no '^break''^ to 550° F., and to keep it at that tem- 
perature or slightly over until it becomes very heavy 
and viscous. Its specific gravity changes from .930 to 
.980, at which point a small quantity placed on a piece 
of glass and allowed to cool piles or stands up in a little 
mound and runs very slowly. With the oil still at 550° 
F., a small quantity of litharge is added; this is known 
as adding the drier on the downward cool, which simply 

' An oil from which no black flocculcnt particles separate at 
500° F. is technically known as an oil which has no "break" or 
does not ''break." 



LINSEED OIL 177 

means that the oil takes up the drier not as the heat is 
increasing but as the heat is decreasing. The amount 
of litharge added is necessarily ver>'^ small, because if 
more than one tenth of i per cent be added the oil 
becomes considerably darkened, while the object in 
making an enamel oil or marble oil is to retain its color. 
Oil made solely with litharge as a drier dries very tacky 
and must be baked to at least iio° F. for several hours 
before it will dry entirely. For this reason many add a 
small percentage of borate of manganese with the lith- 
arge, or chloride and sulphate of manganese, as a drier. 

Of all the driers for making stand oil for enamel 
paints cobalt is the best, for a very small quantity is 
necessary to perform the function of drying and no bad 
results are obtained. Where manganese driers are used 
and continued oxidation takes place a white enamel 
paint may turn entirely pink, due to the formation of a 
manganese salt of that color. Where lead is used slow 
and sticky drying may result, but where lead and 
manganese are used together in dark colored enamels 
excellent results are obtained and any change in color 
value is not noticed. 

Some stand oils are made also by partial oxidation or 
blowing and partial heating. These, however, are short, 
and when placed between the thumb and forefinger and 
rubbed rapidly do not form a long thread but a short 
thread. Experience has taught that a short oil is short 
lived and a long oil is long lived. There is obviously a 
good reason for this, as the short oil has been highly 
oxidized and continues to oxidize after it is dry. Yet for 
interior enamel purposes a short enamel oil will last many 
years. 

One of the best features of enamel oil or stand oil is 
that brush marks even with a poor brush are eliminated 



178 CHEMISTRY AND TECHNOLOGY OF PAINTS 

and flow together. Zinc oxid is the principal pigment used 
in the manufacture of all of these enamel paints. 

Japanner's Prussian Brown Oil 

This is a stand oil or marble oil identical in all 
respects with that described under the heading "Stand 
Oil," excepting that it is dark in color and therefore 
only used for making dark colored enamels such as 
patent leather, machinery enamels and waterproof coat- 
ings which must have a high glaze. 

The method used for making this oil depends very 
largely upon the good quality of the linseed oil, and the 
oil must have no tendency to "break" whatever. It 
must be heated to 550°, at which temperature three 
ounces dry or six ounces in oil of Japanner's Prussian 
Brown are added slowly until the oil which at first is 
muddy becomes clear and of the color and consistency 
of dark honey. 

As the present tendency is to varnish or enamel 
automobile parts and bake them at fairly high tempera- 
tures this oil has become of great value, particularly when 
mixed with a fossil resin varnish, and as there are but 
very few automobiles which are painted white the dark 
color of this particular oil is no objection. 

For the manufacture of an enamel paint for painting 
engines which are continually at a temperature of be- 
tween 170° and 212° F. on account of being water jacketed, 
it has been found that the dark enamels used for this 
purpose when made with the Japanner's Brown oil 
containing at least 25 per cent of a high grade fossil 
resin varnish give results that are astonishing. Enamel 
paints on an engine, composed of the materials just 
described, will at the end of a year be practically as good 
as the day that they were applied. 



UNSEED OIL 179 

Typical Analysis of Heavy Bodied Blown Oil 

Specific Gravity 988-.993 

Saponification Value 195-210 

Iodine Value 100-140 

Acid Value 4-6 

Typical Analysis of Enamel Oil 

Specific Gravity .9678 

Iodine Value i74-5 

Saponification Value 1950 

Acid Value 7.3 



CHAPTER XIII 
Chinese Wood Oil 

Chinese wood oil (China wood oil), or, as it is some- 
times known, Japanese wood oil or Tung oil, is very largely 
used in the United States, but there appears to be very 
much secrecy with reference to its manipulation. 

It is a peculiar fact that the majority of writers on this 
oil are inclined to condemn it, for the principal reason 
that when China wood oil, as it is commonly called, is 
bruslied out on a sheet of glass it dries in about 12 hours 
to an opaque film which presents a rough appearance 
anil does not adhere very well to the glass. It is per- 
fectly true that this is a characteristic of China wood oil, 
aiul it is likewise true that it has no elasticity and that 
its waxlike appearance after drying condemns it very 
thoroughly, but it only goes to prove the difference 
between theory and practice, for, whereas China wood 
oil in its raw state is totally unfit for use and spoils any 
gvH>ii paint to which it may be added, when properly 
treated it is one of the most remarkable paint assistants 
\\l\ie!\ we have, and those who have studied the subject 
earefully have made ver}^ successful paints. 

It might be proper to cite as a parallel case that it 
would be manifestly unfair to condemn meat as an article 
ol (li(*t for tlie reason that it is tough, difficult to mas- 
tic al(\ 'nsipid in its taste, and hard to digest. On the 
i»tl\ir hand, the excellent flavor and nutritious qualities 
\»l meat which has been properly cooked and seasoned 

(olally disproves the first statement. It is evidently 

180 



CHINESE WOOD OIL i8i 

very unfair to compare raw meat with properly cooked 
meat. 

In the winter time, at ordinaiy^ freezing temperature, 
China wood oil looks like a mixture of tallow and sand 
and has a similar consistency. The head of the cask is 
removed, the oil cut out in slices and put into a kettle 
for treatment. 

It is pretty well agreed that at 450° F. China wood 
oil gelatinizes, and if allowed to cool becomes insoluble. 
But experts in the manipulation of China wood oil add 
metallic salts or resinates at this temperature and a 
small percentage of untreated linseed oil, and before it is 
sufficiently cool small quantities of naphtha and benzol. 
The resulting liquid is a clear varnish-like oil which dries 
with a hard elastic film, much more slowly than the 
original China wood oil. In this condition it possesses 
most remarkable qualities.. 

By the use of China wood oil paints are made which 
dry in damp atmospheres. The advantage which the 
Chinese and Japanese have had over the Europeans on 
this subject has been recognized for a long time. It is 
now known to have been due to their knowledge of the 
proper manipulation of China wood oil. For the making 
of marine paints and waterproof paints China wood oil is 
indispensable. 

In the United States preference is given to two brands 
of China wood oil; one is called the Hankow and the 
other the Canton, the Hankow being the better of the 
two. The Canton oil is darker, and it is wtry likely that 
it is expressed from the seed by a hot process, whereas 
the Hankow oil is expressed by the cold process. 

The chemical constants of China wood oil are about 
the same as those of linseed oil, its specific gra\dty being 
slightly higher in the third decimal, its iodine value rather 



l82 CHEMISTRY AND TECHNOLOGY OP PAINTS 

lower, and its saponification number almost the same^ The 
oil has, however, a characteristic odor which cannot be 
easily destroyed, and a paint miaiiufacturer who is once 
familiar with this odor can never be deceived. At the 
same time, where a small quantity of China wood oil is 
used for the purpose of making a particular kind of cal- 
cium oleate, it loses its characteristic odor. The calcium 
oleate so obtained is eventually split up by atmospheric 
moisture, and is therefore valuable for making a cement 
paint which has been patented.^ 

China wood oil is largely used in the making of enamel 
paints. Such paints give perfect satisfaction, last longer, 
and wear better than many of the resin varnish enamels. 
This work does not treat of enamel paints, although these 
paints could be classed as mixed paints, because they are 
a mixture of varnish or oil and pigment. As the ratio of 
the ingredients is totally different from that of oil-mixed 
paints, the subject of the use of China wood oil in these 
enamels has no place in this chapter. Where a manu- 
facturer is at liberty to use any material, China wood 
oil can in no sense be regarded as an adulterant. It is 
more expensive than linseed oil and only on one or two 
occasions has the price of linseed oil approximated that 
of China wood oil, but even if the two in their raw state 

^ The constants of a sample of China wood oil were compared with 
those of linseed oil in 1906, and it is of interest to know that the same 
sample was reanalyzed by the author in 1915, with the following 

results. 

1906 1915 

0.935 Sp.gr. = 0.953 at 60'' F. 

Acid Value = 8.1 

190 Sapon. Val. = 194.7 

165 Iodine Val. = 146.6 

The oil was kept in a glass-stoppered bottle. It had become very 
thick, viscous and clear. 



CHINESE WOOD OIL 183 

were exactly the same in price, China wood oil would be 
very much dearer eventually on account of the high cost 
of manipulation. All factory experience indicates that 
the manipulation of China wood oil increases its cost 20 
per cent if based on a cost price of 50 cents per gallon, 
whereas by the same manipulation the price of linseed 
oil would be increased only 5 per cent. 

Tung oil is probably the glyceride of two acids — 
elaeomargaric and oleic, while linseed oil is probably the 
glyceride of three acids. China wood oil has two peculiar 
qualities which make it very valuable for the manu- 
facture of floor paints. The first is, its resistance to 
moisture, and the second, its extreme hardness so that 
it does not show scratch marks. For the manufacture 
of floor paints for railway and steamship use, these 
two qualities are essential. On the ferry-boats floating 
in the rivers of the United States it is customary to wash 
the floors several times a day. A linseed oil paint soon 
becomes spongy and is destroyed by this treatment. A 
floor paint composed of a large amount of China wood 
oil and a small amount of resin does not show a heel 
mark very readily, which is a decided advantage. 

The Japanese are, however, more adept in the manip- 
ulation of China wood oil than any other nation. The 
author has three samples of varnish oil, one of which 
has almost the consistency and appearance of chemically 
pure glycerin. It has a faint yellowish tinge, and while 
it is no better in its physical characteristics than the 
nominally treated China wood oil, it indicates that 
without destroying any of its good qualities the Japanese 
can prepare this oil for lacquer and enamel purposes until 
it is practically water white. 

It is a known fact that there has been great secrecy 
among the paint and varnish makers on the question of 



i84 CHEMISTRY AND TECHNOLOGY OF PAINTS 

China wood oil, and those who have used it successfully 
have forged ahead of their competitors. Its moderate 
use in a waterproof paint or damp-proof pamt is of great 
benefit. Its use as a mixing varnish or combining 
medium in mixed paints is likewise of great value. 

In its constants it is analogous to linseed oil, and it 
always has a most characteristic odor by which it can be in- 
variably distinguished. It is, however, frequently subjected 
to adulteration with cheaper oils, and one of the first 
samples the author ever received was shipped from China 
in a 5-gallon kerosene tin which contained a considerable 
quantity of kerosene, either accidentally or intentionally. 
The oil from Canton, according to the experience of the 
author, is by no means as good as the oil from Hankow, 
the Hankow oils being paler in color and responding 
more clearly to the accepted chemical constants. One 
of the best tests for the determination of the purity of 
China wood oil is to heat it very slowly in boiling water 
for an hour; then transfer the test to a naked flame and 
heat it for twenty minutes to 450° F. Some care must 
be exercised not to flash the oil nor to char it. It is 
then allowed to cool, a good method being to place it in 
cold water for half an hour, after which time the oil 
must assume the appearance of an almost solid gelatin. 
The admixture of any adulterant, particularly cotton- 
seed oil, prevents the coagulation or semi-solidification 
of China wood oil. 

In order to manipulate China wood oil for paint 
it must be treated with an organic acid salt of lead 
and manganese which is sold for the purpose. A 
number of paint manufacturers have treated China 
wood oil with great success in the following manner: 10 
gallons of China wood oil are slowly heated in a copper 
kettle to 350° F., and 10 pounds of this organic salt are 



CHINESE WOOD OIL 185 

added. When entirely dissolved, which takes but a very 
short time, 5 gallons of refined linseed oil are slowly 
stirred in and the whole heated to 400° F. and kept at 
that temperature for half an hour. The kettle is now 
withdrawn from the fire, and 2^ gallons of either tur- 
pentine or benzine, or a mixture of both, are added. 
This oil, known as China base oil, is then used in varying 
proportions in mixed paints for smoke stacks, floor 
paints, and varnishes, according to the experience or 
knowledge of the manufacturer. 

The chemical detection of China wood oil is still 
somewhat empirical when it is contained in paints or 
varnishes. Some years ago the author made the state- 
ment that China wood oil could always be identified to 
a greater or lesser degree on account of its '^ heathen" 
odor. Anyone familiar with China wood oil or while 
cooking it can identify it at once. This may be em- 
pirical, but it is just as positive as the odor of fish 
oil when heated, and as the chemist has to depend to 
quite some extent upon his sense of taste and smell, 
the sense of smell when heating a varnish under exam- 
ination is a fair guide when oils which have a specific 
odor are contained. 

Formerly very little attention was paid to the acid 
figure of China wood oil, but today this acid figure plays 
a very prominent role. It is definitely known now that 
the high acid number of China wood oil prevents it 
from being used for making enamel varnishes where zinc 
or lead is used, for the reason that these pigments act 
as bases and thicken the resulting enamel paint. It is 
therefore either necessary to neutralize the acids or to 
use a pigment which is not attacked, like lithopone. 

The polymerization of China wood oil is not under- 
stood. According to the patent of Beringer the addition 



s 



1 86 CHEMISTRY AND TECHNOLOGY OF PAINTS 

of a sulphur compound prevents the polymerization. The 
author has made experiments using barium sulphide and 
finds that i per cent of barium sulphide prevents poly- 
merization, but the addition of any one of these materials, 
including sulphur or selenium compounds, paralyzes the 
drying quality of China wood oil. 

China wood oil plays a very . important r61e in the 
manufacture of flat wall paints and neutralizing fillers 
and varnishes for the painting of Portland cement. 
From the analyses of various types of China wood oil 
that hUve come to the laboratory of the author it was 
noted that its acid number is considerably higher than 
•that of linseed oil, and therefore care must be taken in 
the selection of the pigments with which China wood oil 
is ground, or else livering will ensue. As for instance, in 
the making of an enamel paint in which zinc oxid is used, 
the enamel paint may keep in suspension or be preserved 
as a ready mixed paint for several weeks, but at the end 
of a week it will gradually grow thicker until finally it 
becomes loo thick for use. This is due entirely to the 
f;ui llial the free organic acid of the China wood oil 
combines with the zinc or other base and forms a com- 
])()un(l. Tn order to overcome this a fair knowledge of 
the eiiemistry of the pigments is necessary, and neu- 
Iraliziition of the China wood oil must first take place 
before it is heated or converted into a varnish oil. 

In a ])revious chapter which was written nearly ten 
years a^o tlie author made the statement that raw 
Cluna wood oil is not used to any great extent; in fact, 
it has always been regarded that raw China wood oil is 
decidedly unfit for use and spoils any paint to which it 
ma\' be added, but since the flat wall paints and the 
Portland cement i)aints have come into use the addition 
of a small percentage of raw China wood oil has been 



I 



CHINESE WOOD OIL 187 

found beneficial not only for producing flat surfaces but 
for producing a surface upon which a subsequent coat 
of paint will adhere better than it would to a surface 
which contained no raw China wood oil. 

China wood oil has particularly good qualities for 
coating Portland cement surfaces, but this invention is 
fully covered by patents 

In the manufacture of baking enamels most excellent 
results have been obtained where China wood oil is 
prepared with soya bean oil at a temperature of 520° F. 
with or without the presence of resins or rosin. Rosin, 
of course, is not recommended in any high grade baking 
or stoving varnish, because it will distill and produce 
either a flat surface or one which will alligator, but the 
fossil or semi-fossil resins when added to a mixture of these 
two oils produce baking varnishes which are particularly 
good for' the hoods of automobiles or the radiators, which 
are alternately hot and cold. 



A Method for the Detection of Adulteration of 

China Wood Oils.^ 

*^\bout July 15, 191 2, there appeared a paper pub- 
lished by the New York Produce Exchange, which spoke 
of the Bacon method for the detection of at least 5 per 
cent adulteration of China wood oils. The paper set forth 
that the suspected oils were to be placed in a bath of 
between 280° and 285° C. for 8| or 9 minutes. To detect 

^ U. S. Letters Patent J^J"©. 813,841.. 

- This paper was presented by Louis S. Potsdamer before the 
Eighth International Congress of Applied Chemistry, 191 2, Section 
Ve, "Paints, Drying Oils and Varnishes," of which the author was the 
President. This paper was written tinder the direction of the author 
and emanated from the research laboratory of Toch Brothers. 



i88 CHEMISTRY AND TECHNOLOGY OF PAINTS 

adulteration after polymerization the oils were to be cut 
with a knife, the pure oflFering little or no resistance to 
cutting and showing a clean cut surface; while the adul- 
terated under similar treatment displayed a ragged cut, 
or else it could not be cut at all. 

This was given a fair trial in the research laboratory 
of Toch Brothers' paint factory, with little success, until 
I decided to note the temperature of polymerization of 
the various samples, adulterated and pure. I had 
several samples of the pure oil, and these I made up into 
stock solutions as foUows: 

Pure, 

5 % Adulteration with Soya Bean Ofl - 
io% " " " " " 

7 % " " Paraffin Oil 

io% " " " " 

(Soya bean and paraffin oils were chosen as representative of v^e- 

table and mineral oik respectively.) 

The apparatus used was such that a bath of oil 
(pure soya bean oil) was placed in a nickel pot of about 8 
inches diameter. In this were suspended two test tubes, 
arranged to act as an air bath. The samples were placed 
in tubes of slightly smaller bore, and in turn in the air 
bath. Thermometers were suspended in these tubes so 
that the mercury bulbs extended below the middle of the 
oil under examination. 

The bath was first heated to a temperature be- 
tween 510° and 525° F., and the sample tubes, filled 
so that the oil surface did not extend above the sur- 
face of the bath, then placed in position. They were 
allowed to remain in this position until polymerization 
just set in, stirring once in a while with the ther- 
mometers. 



CHINESE WOOD OIL 189 

At the point of polymerization the temperature was 
noted and the tubes withdrawn from the bath. Referring 
to the tables one can see that adulterations as low as 5 
per cent cause a very perceptible drop in the temperature 
of polymerization. 

I made only three sets of oils, but from these I 
obtained results on which I base my method for the 
detection of adulteration. I found that the first two oils 
under examination had an average polymerization tem- 
perature of 553° and the third (a mixture of two sup- 
posedly pure oils received at Toch Brothers' factory for 
testing) a somewhat lower temperature. 

Disregarding such a small discrepancy, 15° F., we 
notice that the adulteration caused a decided drop in 
the polymerization temperature, and as soya bean oil 
is handiest to the oriental, we may expect adulteration 
with this. 

By the method herein described, an adulteration of 
5 per cent could be detected. To settle this finally I 
offer this suggestion: that the American Society for 
Testing Materials now working on the standardization 
of soya bean and China wood oils add the above to 
their tests and so obtain a standard temperature of 
polymerization in the manner described, and all oils 
meeting such a temperature (or those within a small 
range) call pure. It would then be a very simple matter 
to detect adulteration. 

Supplementing the polymerization test the specific 
gravities of the oils were determined under standard 
conditions (60° F.). It was noticed that the higher the 
percentage of adulteration the lower the specific gravity, 
and further, when the adulteration was mineral oil the 
specific gravity was lowered at least four times as much 
as with a similar percentage of vegetable oil. 



IQO 



CHEMISTRY AND TECHNOLOGY OP PAINTS 



Polymerization Temperatures 



Sample 



Pure 



Set I 
Aver. 

SS3 



Set 2 
Aver. 



Set 3 
Aver. 



5 % Soya Bean Oil 

adulteration . 
io% Soya Bean Oil 

adulteration . 
S%ParaflinOil 

adulteration . 
io% ParaflSn Oil 

adulteration . 



SSI 
554 
522 
1 516 
502 

^498 
516 S16 

513 

513 514 

1 515 



552 

554 

519 520 

514 
500 476 



474 
518 

516 
489 
492 



553 



517 



475 



517 



491 



537 



503 



538 

535 

505 

500 

498 499 

500 
494 
Soo 
488 

492 



497 



490 



Sp. Gr. at 60'' F. 



Sample Set i Set 2 Set 3 

Pure 0.9423 0.9416 0.9409 

5 % Soya Bean Oil Adulteration 0.9417 0.9407 0.9391 

10% " " " " 0.9410 0.9401 0.9381 

5 % Paraffin Oil " 0.9348 0.9350 0.9326 

10% " " " 0.9330 0.9323 0.9310 

Iodine values were also made in the samples, with the following 

results: 

Sample Set i Set 2 

Pure 160.4 158.8 

5 % Soya Bean Oil Adulteration 158.0 155.4 

10% " " " " 156.2 151.9 

5 % Paraffin Oil " 155.2 150.8 

10% " " " 143.9 143.4 

The impurities make quite an appreciable lowering in the iodine 

values." 



Set 3 

150-5 
147.8 

141.6 

140.5 
136.8 



Standard Specifications for Purity of Raw Chinese Wood Oil^ 

Properties and Tests 
I. Raw Chinese wood oil shall conform to the following require- 



ments 



^ Amer. Soc. Test. Materials 191 5, 423. 



CHINESE WOOD OIL 191 

Max. Min. 

Specific Gravity ^ C o-943 o-939 

Acid Number 6 

Saponification Number 195 190 

Unsaponifiable, per cent 0.75 

Refractive Index at 25® C 1.520 1.515 

Iodine Number (Hiibi 18 hrs.) 165 

Heating Test (Browne's Method), minutes . . 12 

Iodine Jelly Test, minutes 4 



CHAPTER XIV 
Soya Bean Oil^ 

From 1890 to 1909 the price of linseed oil fluctuated 
between 30 cents and 50 cents per gallon. On a few 
occasions the prices were higher, but a fair average for 
the 19 years was 40 cents per gallon, although in 1896 
it went as low as 25 cents. Toward the end of 1909 it 
rose from 60 cents to 68 cents withm two months, 
and in September, 1910, it reached $1.01 per gallon. 
After that it fluctuated between that price and 75 cents. 
Owing to the high price of linseed oil in 1910 many 
painting operations were deferred awaiting a lower price, 
or inferior material was used in place of linseed oil. 

The value of menhaden fish oil had already been 
recognized, and while it is admitted that fish oil replaces 
linseed oil for many purposes, it is by no means a true 
substitute. The principal use, however, for fish oil to- 
day is in the manufacture of linoleum, printing inks, and 
certain paints which are exposed either to the hot sun 
or on hot surfaces. 

In 1909 soya bean oil as a paint oil was practically 
unknown. Since that time many investigators have 
published more or less conflicting articles concerning 
soya bean oil, in which even the physical and chemical 
constants of soya bean oil varied to some extent. Owing 
to the fact that discordant results were continually ob- 
tained, it is only within the past few years that it has 

' Journal of Society of Chemical Induslr>*, June 29, 1912, No. 12, Vol. 

XXXI, by Maximilian Toch. 

192 



SOYA BEAN OIL 193 

been possible to state with some degree of certainty 
whether soya bean oil is a substitute for linseed oil, an 
adjunct to it, or neither. The reason for this uncertainty 
and discrepancy is apparent when it is stated that the 
author himself has experimented with 33 different varie- 
ties of soya beans, while in the records of the Department 
of Agriculture at Washington no less than 280 varieties 
of soya beans are listed. 

From time immemorial the soya bean has been 
grown in China and Japan, where it has served as one of 
the staple articles of food and as the basis for a number 
of food preparations. In Europe and the United States, 
however, the value and uses of the bean have been but 
little appreciated until very recently (1908), when, on 
account of the scarcity in the cotton seed supply of the 
world, soap and glycerin manufacturers began to turn 
their attention to its possibilities. In Manchuria, where 
by far the major portion of soya beans are grown, 
practically the entire crop is available for export. The 
following figures taken from the Consular Reports will 
serve to show the extent of the soya bean industry during 
recent years: 

1909 I9IO IQII 

Tons. Tons. Tons. 

Total shipments of beans from 

Far East 1,470,870 1,200,000 1,500,000 

Imported into Europe 400,000 500,000 340,000 

As the above statistics indicate, China and Japan 
retain for domestic consumption practically two-thirds 
of the available supply of beans. The sugar plantations 
in Southern China and the rice fields of Japan annually 
consume enormous quantities of soya beans and bean 
cake as fertilizer, while the extracted oil is used as food 
by the natives. 



194 CHEMISTRY AND TECHNOLOGY OF PAINTS 

In connection with the use of soya beans and soya 
bean oil for edible purposes, it may be mentioned that 
there has been recently established at Les Val6es, France, 
a thoroughly up-to-date factory for the production of a 
wide assortment of food products from soya beans. 
Among the more important of these may be mentioned: 
milk, cheese, casein, oil, jellies, flour, bread, biscuits, 
cakes and sauces. According to Dr. G. Brooke, Port 
Health Officer of Singapore, the soya bean, more nearly 
than any other known animal or vegetable food, contains 
all the essential and properly proportioned ingredients of 
a perfect diet. 

All soya beans are leguminous plants, which do not 
tend to deplete the soil of nitrogen, for the typical soya 
bean plant is self-nitrifying and grows in almost any 
soil that contains a reasonable amount of potash. In 
addition to this, the soya bean enriches even very poor 
ground when used as a ground manure. This is done by 
planting the seed promiscuously, allowing it to grow to a 
height of about 6 inches, and then turning it in. In this 
way both nitrogen and potash are given to the soil for 
future use in an available form. The average height of 
the soya bean plant is about 36. inches. The pods 
resemble those of our sweet pea. They are about 2^ 
inches in length and are covered with a hairy growth. 
Generally there are two or three beans in each pod. 
Af,ter the oil is extracted from the bean the cake 
appears to be ver>^ valuable as a cattle food, while the 
leaves and stalks, if collected and set in a dry place, 
make excellent silage. We thus have practically the 
entire plant available for use, with the exception of the 
roots. 

The average composition of the soya bean varies with- 
in fairly narrow limits among the different varieties 



SOYA BEAN OIL 



195 



of soya beans. In the following table are listed the 
analyses of a few of the varieties of soya beans :^ 



Variety 



Austin 

Ito San 

Kingston .... 
Mammoth . . . 

Guelph 

Med. Yellow. 
Samarow. . . . 









Nitro- 




Water 


Protein 


Fat 


gen free 
extract 


Fibre 


% 


% 


% 


/O 


/o 


8.67 


36.59 


20.55 


24.41 


4.00 


7.42 


34.66 


19.19 


27.61 


5.15 


7.25 


36.24 


18.96 


26.28 


4.79 


7-49 


32.99 


21.03 


29.36 


4.12 


7.43 


33.96 


22.72 


25.47 


4-57 


8.00 


35-54 


19.78 


26.30 


4.53 


7.43 


37.82 


20.23 


23-65 


5.05 



Ash 



/c 



5.78 

5-97 
6.28 

5-OI 

5.85 

5-85 
5.82 



When the author obtained discordant results from 
the soya bean oil then on the market, the first impression 
was that the oil might have been adulterated, but this 
did not prove to be the case. The oil was, in all cases, 
pure soya bean oil, but from a seed which was not par- 
ticularly adapted for making a paint oil. Through the 
U. S. Department of Agriculture many varieties of seeds 
were received, and through the various seed dealers in 
the United States quantities of seeds of all kinds were 
purchased. The method of extraction followed was to 
grind the seeds very finely in a mill and digest with gaso- 
line in the cold. The solvent was then evaporated and 
the oil recovered. Without going into any lengthy de- 
tails, the percentage of oil extracted averaged 18 per cent, 
and although soya beans range in color from a cream 
white to a jet black it must be noted here that all the 
oils extracted from the various seeds were paler than 
finely pressed linseed oil, and none of them showed the 

^ U. S. Dept. of Agric. Bulletin of the Bureau of Plant Industry. 



196 CHEMISTRY AND TECHNOLOGY OF PAINTS 

chlorophyll extract as markedly as. fresh flaxseed. On 
obtaining the various samples of oil it became evident 
why the discordant results were obtained, for some of 
them dried within a reasonable time and some did 
not. 

It has been stated that soya bean oil is not as pale 
as raw linseed oil and belongs to the semi-drying class 
of oils. I must correct this statement; soya bean oils 
made from cold pressed seeds such as Haberlandt, Austin, 
Habaro, Ebony, Meyer, and Ito San give excellent results. 
They have a specific gravity as high as 0.926, with a yield 
ranging from 16 to 19 per cent. Furthermore, a drier 
made from red lead or litharge is unsuited for soya bean 
oil, but a tungate drier, which is a mixture of a fused 
and a precipitated lead and manganese salt of China wood 
oil and rosin, acts on soya bean oil exactly the same as a 
lead and manganese drier acts on linseed oil. In other 
words, a fairly hard, resistant ^nd perfectly dry film 
is obtained within 24 hours by the addition of from 
5 to 7 per cent of this drier. 

Soya bean oil, and when I mention this name here- 
after, I refer only to that suitable for paint purposes, 
is the nearest oil we have to linseed, and under 
the proper impetus of the Department of Agricul- 
ture much of our waste and unproductive land 
between Maryland and Georgia, and from the Coast 
to the Mississippi, will yield productive and profitable 
croi)s. The only drawback to the planting of soya 
bean is the fact that it needs much water. In 191 1 
many of the experimental plantings failed on account 
of the drought which was prevalent in the United 
States, but in low marsh land this plant ought to yield 
a profitable crop. It is doubtful whether the soya bean 
would grow profitably in the extreme South. In Cuba 



SOYA BEAN OIL 197 

the cow-pea, which is analogous to the soya bean, will 
sometimes grow to a height of 20 feet, and form a thick 
mat aroimd the base or abutment of a railroad bridge, 
and that within a few months. This would indicate that 
a soil would have to be selected where the bean would 
not grow to a height greater than 5 feet, otherwise the 
stalks would be too thick and it would be difficult to 
harvest it. Farmers' Bulletin No. 372 of the Department 
of Agriculture makes the statement that 20 lbs. of seeds 
are required to the acre, and that the production is from 
25 to 40 bushels, each bushel weighing 40 lbs. If this is 
a fact, and since little or no fertilizer is needed, and 
when fertilizer is needed a preliminary crop can be grown 
and turned in to form its own fertilizer, the American 
farmer should be encouraged to try this crop. Fur- 
thermore, in Kentucky two crops during the summer can 
be grown, for some of the soya beans that have been 
tried there have ripened early, and the second crop has 
ripened late, two different selections of seed having been 
used. The statement has been made that soya bean 
could not be harvested properly in this country on 
account of the high cost of labor as compared with that 
of Manchuria and Japan, but this is evidently erroneous, 
in view of the fact that enormous quantities of beans are 
grown in Minnesota for food purposes and harvested 
by machinery. Even in Manchuria the beans are allowed 
to dry and then thrashed out by means of horse power. 
At any rate, if we have any difficulties now with the 
harvesting of a new kind of crop, it is safe to assume that 
with the American inventive genius in harv^esting ma- 
chinery, appliances will be invented which will overcome 
this, for the soya business has no greater harvesting 
difficulties than the edible bean. 

Soya bean oil appears to consist of from 94 to 95 



igS 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



per cent of glycerol esters.^ Of these 15 per cent are 
saturated acids such as palmitic acid, and 80 per cent are 
liquid unsaturated fatty acids containing 70 per cent 
oleic acid, 24 per cent linolic acid, and 6 per cent linolenic 
acid. The iodine number of soya bean oil has been 
given as ranging from 121 to 124, but the Manchurian 
cold pressed oil will average as high as 133. 

It may be of interest to show a comparative table 
here between the physical and chemical constants' of 
soya bean oil of known origin like Manchurian cold 
pressed oil as compared with linseed oil. 



Soya Bean Oil 



Name 



Meyer Brown 

Peking Black 

Straw- 



Haberlandt 



Farnham 



Taha 



Mammoth. . 



Edward 



Shanghai. 





yellow 
Straw- 
yellow 
Black, 
olive 
saddle 
Straw- 
vellow 
Brown 
f Straw- 
[ yellow 



extremely 
pale 



pale amber 
somewhat 
deeper than 
above 



1 



Black 



j' med. amber 

;' same depth 
as previous, 
olive tone 



Refined linseed oil 



0.9264 
0.9279 

0-9234 
0.9234 



0.9248 

0.9222 

0.9248 
0.9257 



0.9241 



0.933 



Acid 
value 



0.44 
0.14 
0.00 



0.16 

0.47 

0.17 
1. 14 



0.63 



i.o 



Iodine 
value 



127.0 

135-4 
129.8 



0.65 I 131.8 



127.0 
I18.2 

I2Q.3 
124.6 



127.8 
1 80. 1 



^ H. Matthias and H. Dahle — Arch. Pharm., 191 1, 294, 424-435. 
- Results obtained in the research laboratorv of Toch Brothers. 



SOYA BEAN OIL 199 

The specific gravity determinations were made with 
the pyknometer. The iodine values were obtained in 
accordance with Hubl's method. The iodine values 
indicated are somewhat lower than those of cold pressed 
Alanchurian bean oil. This is no doubt to be ascribed 
to the circumstance that the solvent with which the oil 
was extracted was driven off by. evaporation in open 
vessels on the water bath, so that the oil became slightly 
oxidized. 

Soya bean oil which is suitable for paint purposes has 
two characteristics which enable the chemist to deter- 
mine whether this oil is suitable or not. In the first 
place, soya bean oil when heated up to 500° F. for a few 
minutes will bleach and remain bleached. Some sam- 
ples which the author has examined have turned almost 
water white. Linseed oil has this characteristic, but not 
to the same degree. Cold pressed soya bean oil made 
from the samples indicated in the previous table, when 
heated to 500° F., and blown with dry air for from 5 to 7 
hours, thickens exactly the same as linseed oil, and 
attains a gravity of 0.960 or over. This is the surest 
indication that the soya bean oil which will thicken 
under these conditions and remain pale is suitable for 
paint purposes. This thickened oil has excellent qualities 
and advantages for making what we call in this country 
"baking japans," and what are known in England as 
"stoving varnishes.'' 

A sample of standard cold pressed Manchurian bean 
oil was heated to 500° F., and blown vigorously for 7 
hours after cooling to 300° F. The following results were 
obtained: 



200 



CHEMISTRY AND TECHNOLOGY OF PAINTS 





Sp. gr. 
6o*»F. 


Acid 
value 


Iodine 
value iWijs.) 

• 


Original oil 

Blown oil 


0.929 
0.963 


2.6 

1.9 


1336 
105.3 



It is interesting to note that the acid value was 
reduced by blowing. The blown oil dried in 3I days, 
whereas the original sample required from 5 to 6 
days. 

It appears that the varnish made from a suitable 
soya bean oil bakes very hard and retains an abnormal 
flexibility. As regards the wearing quality of pure soya 
bean oil compared with pure linseed oil for paint, the 
author has had somewhat less than three years' experi- 
ence, and can only say that it is not quite as good as 
that of linseed oil. A 2-year exposure on a 100-foot 
fence gave slightly better results for the linseed oil as to 
hardness and less gloss for the soya bean oil, but a 
mixture of half soya bean and half linseed oil showed 
approximately the same results, while a varnish made of 
25 per cent of China wood oil with 75 per cent soya 
bean oil gave equally hard results as linseed oil. It is 
too soon to prognosticate the value of soya bean oil for 
exterior painting, but for interior painting soya bean oil 
is the equal in ever>^ respect of linseed oil, and particularly 
when treated with a tungate drier. 

Cobalt drier will, under many circumstances, dr>' even 
those soya bean oils which are not suited for paint pur- 
poses, but for the present cobalt drier is rather too expen- 
sive. It has been stated that from i to i^ per cent 
cobalt drier will dry soya bean oil and fish oil. This is 



SOYA BEAN OIL 201 

practically true, but 2^ per cent is really needed to get 
the proper drying within 24 hours. Cobalt Tox 
Tungate^ is probably the ideal drier for soya bean and 
fish oils. This drier, when present in soya bean oil 
to the extent of from 5 to 7 per cent, will dry the 
latter within 12 hours. 

It is, of course, possible to determine and differ- 
entiate a mixture of raw soya bean oil and raw linseed 
oil, for the iodine values and specific gravities are good 
indications, but when 25 per cent of soya bean oil is 
added to a mixed paint neither the author nor any- 
one in his laboratory can, in all instances, detect its 
presence. 

Blown and thickened soya bean oil is already used 
by a number of the linoleum and table oilcloth manu- 
facturers, and for printing ink purposes it presents some 
advantages. For the manufacture of enamel paints 
heavy bodied soya bean oil produces most beautiful re- 
sults, and as perhaps 95 per cent of all enamel paints are 
used for interior decorative or protective purposes in 
this country its use should be encouraged. 

It is not within the province of the writer to forecast 
the future of any paint oil, but there is no doubt that if 
a campaign of education be urged among the farmers, 
particularly in those states where soil has been regarded 
as unproductive, and the proper selected seeds of soya 
beans are planted, no scarcity in the flaxseed crop will 
ever again be a menace to the paint and varnish indus- 
tries. At the time of writing linseed oil is quoted at 75 
cents per gallon and soya bean oil at 55 cents per gallon. 
As soon as thousands of acres shall have been planted 

* So called because it was first prepared by the author. It is a 
cobaltic salt of China wood oil. Unless the cobalt is trivalent, it 
will not act as a drier. 



202 CHEMISTRY AND TECHNOLOGY OF PAINTS 

with soya beans, the proper machinery installed, and the 
sale for the cake and the silage arranged, soya bean oil 
will sell at from 25 to 35 cents per gallon, and after the 
ground has been productive of soya beans for some time 
it will be fit for the growing of even the most difficult 
crops. 



CHAPTER XV 

f iSH Oil 

We are all prone to call all oils of a fishy nature "fish 
oils," and. the author desires to differentiate between the 
real fish oils and the pseudo fish oils, for there are several 
marine animal oils which have fishy characteristics but 
which are not strictly fish oils, and which do not serve as 
good a purpose as those which are strictly extracted from 
fishes. Some of the fish oils — like cod liver oil — even if 
they were cheap enough, are not totally adapted for 
paint use. The animal oils which have always been 
regarded as fish oils, but which the author calls pseudo 
fish oils, and that are in the market and easily pur- 
chased at a reasonable price, are whale oil, porpoise oil 
and seal oil. All of these oils are by no means drying 
oils, and even if they are admixed with drying oils like 
tung oil and boiled linseed oil, and an additional amount 
of drier added, they are peculiarly hygroscopic, and after 
three months, although these oils may be apparently 
dry, they become sticky when the humidity rises above 
80. 

The following figures represent some constants of 
fish oils, the specific gravity and the iodine number 
being given in each case. The iodine number is a char- 
acteristic indication of the value of a fish oil for paint 
purposes. 



203 



204 CHEMISTRY AND TECHNOLOGY OF PAINTS 



Fish Oil Constants 

Specific Iodine No. 
Gravity Hubl, 
20** C 4 hours 

No. I crude whale oil o-QiQS 136.1 

No. I filtered whale oil 0.9168 125.0 

No. 2 filtered whale oil 0.9187 142.9 

Cod oil 0.9196 147.3 

Porpoise body oil 0.9233 132.3 

Seal oil — water white 0.9227 143.0 

Menhaden Oil 

Extra bleached winter 0-9237 150.4 

Bleached — refined 0.9273 161. 2 

Regular 0.9249 165.7 

Dark brown 0.9250 154.5 

The specific gravities were determined with the aid 
of the Westphal balance. 

The iodine numbers were determined according to the 
standard method of Hiibl. 

The fish oil used for paint purposes is the variety 
obtained from the Menhaden fish, and the winter bleached 
is the variety to be recommended. When refined by 
the simple process of filtering through infusorial earth 
and charcoal its color is that of refined linseed oil, with 
little or no fishy odor; in fact, in the purchasing of fish 
oil for paint purposes it is well to beware of a fish oil 
that has the so-called characteristic '^ fishy" odor. In 
its chemical properties it is so similar to linseed oil that 
it is difllcult to differentiate between them. It must 
be observed that oils in mixed paints are not presented 
to the chemist or practical man in their raw or natural 
state, but they have been boiled with driers and ground 
with pigments so that their characteristics are entirely 



FISH OIL 205 

altered. The old-time painter when he condemned a 
mixed paint would smell it, taste it, rub it between his 
thumb and forefinger, smell it again, look wise, and say 
despairingly, "fish oil." As a matter of fact, the adul- 
teration of paints was seldom, if ever, caused by the 
addition of fish oil, for the reason that the price of a 
good fish oil always approximated that of a raw linseed 
oil, and there were so many other cheaper paraffin oils 
to be had that the occurrence of fish oil in a mixed 
paint was relatively rare. The specific gravities of fish 
oils freshly made and containing no admixture of other 
species, but representing the pressing of only one species, 
are as a general rule below .927. Its iodine number is 
so close to that of linseed oil that in its raw state, except- 
ing for its characteristic odor and the Maumene test, it 
is rather diflScult to differentiate these oils with cer- 
tainty. The author is inclined to believe that this 
characteristic odor is due to phosphorous decomposition 
compounds. If a linseed oil be heated to 500° F., mixed 
with Japanners Prussian brown or Prussian blue, it de- 
velops acrolein, which is identical in odor with that from 
the fish oil. When Menhaden oil is treated with 8 ounces 
of litharge to the gallon and kept at a temperature of 400° 
to 500° F., for ten hours, it thickens perceptibly and can 
be reduced proportionately with naphtha, but the amount 
of loss by this treatment with litharge makes it very 
expensive in the end. 

The results obtained from the proper grades of fish 
oil warrant the use of fish oil in the hands of an intelli- 
gent manufacturer, and if used up to 75 per cent pro- 
duces excellent results for exterior purposes. For interior 
purposes fish oil does not seem to be desirable, for it 
gives off noxious gases for a long time. When fish oil 
is mixed with linseed oil even up to 75 per cent it 



2o6 CHEMISTRY AND TECHNOLOGY OF PAINTS 

gives excellent and lasting results and does not show 
any hygroscopic properties, but when used in the raw 
state, particularly in conjunction with pigments which in 
themselves are not catalytic driers, the results are not 
satisfactory. 

For some years some of the enamel leather and print- 
ing ink manufacturers have adopted the use of fish oil 
as a medium to replace linseed oil with excellent results, 
and the enamel leather which is produced, while not so 
high in gloss as that made entirely of linseed oil, is much 
more flexible and possesses an unctuousness which pre- 
vents it from cracking. But fish oil for leather purposes 
shows a peculiar defect, and a campaign of education 
will be necessary if ever this material is to be used for 
the manufacture of shoes or auto tops, for fish oil, par- 
ticularly when it originally has a high acid number, seems 
to effloresce and give an undesirable bloom to enamel 
leather, which, however, can be removed from the sur- 
face by the ordinary application of either benzine or a 
mixture of benzine and turpentine. At the same time, 
enamel leather is very largely used for carriage and 
automobile tops, and for shoes, and wherever it is used 
for these purposes these products are continually polished. 

Menhaden oil is the only oil, with the possible excep- 
tion of China wood oil, which can be used for making 
smoke-stack paints that will withstand the action of 
excessive heat and light. When treated as described, its 
intrinsic value is far beyond that of linseed oil, and a 
smoke-stack paint made in this manner sells for one-third 
more than a linseed oil paint. It is impossible, however, 
to treat Menhaden oil for this purpose, except at an 
excessive cost, because the acrolein developed nauseates 
the workmen, the loss in evaporation is very large, and 
the treatment with litharge is such that the oil must 



FISH OIL 207 

be thinned before it has an opportunity to compound or 
semi-solidify. In its raw state, after treatment with 
animal charcoal and infusorial earth, it is used to some 
extent with a heavy boiled linseed oil for making water- 
proof roof paints, for painting canvas, freight cars, ship 
decks, etc. When mixed with linseed oil up to about 
25 per cent it is extremely difficult to determine the 
amount present by means of its chemical constants or 
characteristics. 

The following are the constants of the Menhaden oil 
which is generally used in the United States for making 
heat-resisting paints: 

Constants of Fish Oil 

Specific Gravity 0.931 

Saponification 190. 

Iodine Value 150-165 

There is a great demand for baking japans which 
shall be flexible and at the same time be so thoroughly 
baked that they adhere to the surface most tenaciously 
and form an excellent enamel, and for this purpose we 
know that the reasonable use of fish oil improves baking 
japans very much indeed. 

We are also aware that along the seacoast, where 
paint disintegrates very rapidly on account of the sea 
air, a fairly liberal use of properly treated fish oil serves 
a useful purpose. 

When red lead is mixed 33 lbs. to a gallon of linseed 
oil it thickens up after a very short time and becomes 
unfit for use. A properly neutralized fish oil prevents 
the hardening or setting of the red lead in the package, 
and a paste of this material can be transported a great 
distance and will last many months in a fresh and soft 
condition. 



2o8 CHEMISTRY AND TECHNOLOGY OF PAINTS 

In the tests made by the author on fish oils and lin- 
seed oil without the admixture of driers, it was found that 
the Menhaden fish oil and the linseed oil dried approxi- 
mately the same, but the seal oil and whale oil were 
still sticky after two weeks. This may be an unfair 
test, for these other oils can be manipulated with the 
proper driers and they will serve a fairly good purpose, 
but inasmuch as Menhaden fish oil appears to be satis- 
factory for this test even without a drier its superiority 
over the animal oils is apparent. 

Menhaden oil should, of course, be used with a drier, 
and for that purpose the best results are obtained by 
means of a tungate drier. A t ungate drier is one in 
which tung oil or China wood oil is boiled with a lead 
and manganese oxid, and when the solution is complete 
this is then mixed with a properly made resinate of 
lead and manganese. Such a drier becomes soluble in 
the oil at temperatures over ioo° C, and hardens the 
resulting paint very thoroughly. For fabrics, however, 
fish oil must be heated to a temperature of over 200° C, 
and if air is injected at such a temperature the glycerides 
arc expelled and thick oil is produced which, in con- 
junction with the drier just named, is equally good for 
printing inks. It is advisable, however, to add at least 
25 per cent of either a hea\y bodied linseed oil or a raw 
linseed oil which does not ''break'' before the manipula- 
tion just referred to is begun. 

lor stacks, boiler fronts, etc., the treatment of fish 
oil up to 220° C, with litharge makes a heat-resisting 
medium that is far superior to anything excepting China 
wood oil, and for both heat-resisting and exposure to the 
elements fish oil is superior to China wood oil. 

The following is taken from the U. S. Xa\y Depart- 
ment specifications for fish oil for paint purposes: 



FISH OIL 209 

Qualiiy 

1. To be strictly pure winter-strained, bleached, air-blown Men- 
haden fish oil, free from adulteration of any kind. 

Chemical Constants 

2. The oil shall show upon examination: 

Maximum Minimum 

Specific gravity o-935 o-930 

Iodine number (Hanus) 165 145 

Acid number 6 

Physical Characteristics 

3. The oil when poured on a glass plate and allowed to drain 
and dry in a vertical position, guarded from dust and exposure to 
w^eather, shall be practically free from tack in less than 75 hours at 
a temperature of 70° F. When chilled, the oil shall flow at temper- 
atures as low as 32® F. 



CHAPTER X\T 

MgCTTTAXEOrS OiLS 

Herkixg Oil^ 

WiTHix recent years tbc subject of fish oils has 
recetv^ cott^-demble attentioQ^ first from the leather and 
SkXip msiaofiicturers and subsequenth' from the paint 
chemist. Hitherto nsh o3 played the role of a rather im- 
important by-pnxfaict in the course of fertilizer or "scrap" 
pcvxinctioa. for which there seems to have been always 
a Liru^ viemand. 

.\5 the pecxiliar properties and industrial possibili- 
ties of tish otts became more thcMroughly appreciated in 
the light ot investigatioDS carried out by progressive 
Rxanufacturers, the fish oil industr\' received a new 
Uji<e of life and grew until it rix-alled in importance 
:ho fertilizer indusuy to which it had prexnously been 
tributar>-. 

Of the numerous varieties of fish oils which have 
at one time or another appeared uf)on the market, Men- 
haden oil alone seems to have established itself on a firm 
Kisis in the manufacture of special kinds of heat-resisting 
juints. Its application, therefore, is no longer an experi- 
ment: it is an established fact. 

Latterlv, attention has been more particularly directed 
toward seal, whale, cod, porpoise, and herring oils, with 

^ \\v A. LuivNkin, Sth Int. Congress cf Applied Chemistr>'; written 
in tiie n*si^an:h laborator\' of Toch Brothers under the direction of 
the author. 

3IO 



HERRING OIL 2ii 

a view to investigating their utilizability in the indus- 
tries. Of these, seal, cod and porpoise body oils have 
proved to be in many ways as good as Menhaden oil, 
but are beyond the reach of the paint manufacturer on 
account of considerations of price. 

Whale oil, which is now obtainable in the form of a 
clear, pale material, comparatively free from objection- 
able odors, has not as yet been successfully manipulated 
to give very good drying results. 

In the treatment of fish oils, several considerations 
must be constantly kept in mind in order to obtain the 
best results: 

1 . The oil must be free from high melting point 
glycerides or fatty acids; or, to use the technical term, 
the oil must be "winter-pressed." Most fish oils contain 
a large amount of saturated glycerides of the nature of 
palmitin which separate from the oils on standing for 
any length of time at a low temperature. When these 
have been removed from the oil, the resulting product is 
found to be much more amenable to successful treatment 
than it otherwise is. It would seem that these high 
melting point fats tend to retard or to prevent the dr>qng 
of fish oils, giving films which remain greasy for a very 
long time. 

2. Very frequently, oils are received which have a 
high content of free fatty acids. In the case of one 
sample of herring oil, this was as high as 41.9. Under 
such circumstances, it is perfectly evident that the drying 
of the oil would be very largely inhibited. In addition, 
such an oil, used as a paint vehicle, in conjunction with 
pigments like red lead, white lead, and zinc oxid will, 
in a very short space of time, "liver'' up and form the 
lead and zinc soaps of the fatty acids. This was very 
largely responsible for the poor results obtained with the 



irrxr ajtj nt^imiL^^ zs 3 



Tie frss: srrj iocs £:»: Jx ritftf -whcL ^le -ofl. extracted 
rnin '^ isL rj ^imrrrg ii -yy^r, s sz&iected to the 
ic5:iL ic tie oeccinccfffri:iT prMnct? rnaa ibr bocfics erf 
tie -fjarr 5:r :^ ji^msr tzne ttkitt S^ a?yyferrfi" neccssau^' 



*-^ 



Ex X 3]D2S^ be rcoeBbercd tbu diicxs. which 
r^ Sor TTgrfaM^ dn^ing cxisw will not. in 

jKieriL nziictSai zc^j^rh-. wien otSird tor &sh oils. 
Tie tiz:x2itir criers. az>i putinnilirhr the cobalt tmigates. 
OLi ftcerzJh' be depe!:Kkd ii{Mxi in the case of oils which 
do zj'A yjiid to the actioG of the onfimuy linseed oQ 
crlrr*. p^ro-.-fded bawe\"cr. the two concfitioiKS named above 
Livr l^r^zi satisned- 

Tie -sTiter recently had his attention caDed to several 
ZT2.it^ of herring oil, which, at fiist ^biice« appeared 
desirable from the paint mannfaflnrer's standpoint. 
Accordingly an investigation was started to test its 
adaptability for paint purposes, and to OMnpare its be- 
T.ir. T -^-th that of Menhaden oil. 

Herring oil occurs in the bodies of Clupeus C. and 
\'. Japanese herring varieties) and Clupeus harengus 
European or North Sea herring K 

The meth<xi of extracting the oil from herring is the 
one universally used in the fish oil industry*, viz., ex- 
traction in boiling water. 

Two representative samples of herring oil, furnished 
bv two of the leading oil concerns in the States, were 
exiHTimented with in conjunction with Menhaden and 
v>ther nsh oils. The following analytical constants were 
v^btained: 



HERRING OIL 



213 



No. 


Color 


Odor 


Sp. Gr. 


Acid 


Iodine 








iS°C 


Value 


Value 


#1 Herring Oil 


Very Pale 


Good 


0.9240 


2.4 


1379 


§2 Herring Oil 


Dark Brown 


Bad 


0.9210 


41.9 


136. 1 


Blown Oil #2 


Deep Red 


Almost 
None 


0.9654 


25-7 


89.94 


Winter-Pressed 


#2 


Extremely 


Fair 


0.920 


39-4 


136. 1 


Refined J 


Pale 










«**«««««« 












#1 Crude Whale OU 


Very Pale 


Good 


0.9230 


0.6 


136. 1 


#1 Filt. Whale Oil 


Very Pale 


Good 


0.9203 


2.3 


125.0 


#2 Filt. Whale OU 


Pale Amber 


Very good 


0.9222 


14-5 


142.9 


Porpoise Body Oil 


Very Pale 


Very good 


0.9268 


2.8 


132.3 


Menhaden OOs 












Ext. Bleached 












Winter Oil 


Very Pale 


Fair 


0.9272 


05 


1504 


Bleached-Refined 


Pale Amber 


Not bad 


0.9308 


5-7 


161. 2 


Regiilar 


Deep Red 


Bad 


0.9284 


8.4 


165.7 



* The part of the table below the asterisk (with exception of the 
acid values), is from a paper on Fish Oils delivered by M. Toch 
before the Amer. Chem. Soc., Dec. 191 1, and published in the Journal 
of Industrial and Engineering Chemistry. 

Crude herring oil, even though very dark in color, 
yields a very clear, pale product when treated with 
Fuller's earth for a short time at about 250° F., and then 
for some time longer, at the temperature of boiling 
water. In addition the odor is considerably improved. 

In the case of the crude herring oil listed above, the 
sample was kept for several hours at about 60° F. to 
permit high-melting fats to separate out. The portion 
which remained liquid corresponded to a winter-pressed 
oil. Since the acid and iodine numbers were prac- 
tically unchanged it seems that the solid fats contained 
saturated and unsaturated compounds in about the same 
proportions as the crude oil. 



214 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Another sample of the oil was heated to 320*^ F- and 
blown with air for about 8 hours. The eflfects produced 
on the constants are shown above. The oil was^ very 
heavy and viscous but had the deep red color which fish 
oils so readily assume. It must be noted also that the 
'^fish'' odor was very faint. The reduction in acid value 
would seem to indicate that the oil contained fatty acids 
which were volatile at the temperature of blowing. 

Attempts to dry the samples of herring oil did not 
prove successful, even when very powerful driers were 
used. This cannot, however, be interpreted to mean 
that herring oils are, in general, not capable of drying. 

Porpoise body oil and Menhaden oil, under similar 
conditions, dried satisfactorily. 

The blown herring oil could very well be used for the 
production of smoke-stack paints and for paints intended 
to resist the ^'chalking" action of salt air. Herring oil 
is at present used to a certain extent in leather manu- 
facture together with some of the other fish oils like 
Menhaden and whale oil. In regard to herring oil, as 
with many of the other materials which are being intro- 
duced from time to time, the final word cannot be spoken 
until many more specimens have been examined and 
given a fair test. 

Corn Oil 

Corn oil is made in very large quantities in the 
United States, and is of considerable value as a paint 
material. It is seldom so much cheaper than linseed oil 
or China wood oil that it is used as an adulterant for 
these oils; in fact, many manufacturers would probably 
use it irrespective of the price up to about 10 per cent 
in certain classes of mixed paints in order to prevent 
hardening or settling. A large number of paint manu- 



CORN OIL 215 

facturers in the United States who grind heavy paste 
paints, such as Venetian reds, ochres and white paints 
containing large amounts of barytes, frequently use from 
10 to 70 per cent of corn oil, not because.it is any 
cheaper than linseed oil, but for the reason that the 
resulting mass never becomes hard in the package as it 
does where pure linseed oil is used. 

Corn oil has a great analogy to soya bean oil, with the 
one exception that corn oil is not as pale nor can it be 
bleached as pale as soya bean oil, and when it is bleached 
by chemical means it dries very badly. 

Com oil is known in England as maize oil. Paint 
manufacturers in England appear to have very little 
knowledge of this oil and regard it as a non-drying oil, 
and yet com oil is even more than a semi-drying oil, 
particularly when heated with strong drying oils like 
China wood oil and cobalt and manganese drier. In 
the textile arts, such as the manufacture of linoleum and 
table oilcloth, where flexibility is desired, large quantities 
of corn oil are from time to time used with excellent 
results. When an oil like corn oil is used for paint 
purposes in limited quantities its characteristic of slow 
drying or tacky drying is eliminated if it is properly ma- 
nipulated. Corn oil will take up the lead and manganese 
salts just the same as linseed, but in conjunction with 
linseed oil. It can be blown and can be thickened by 
heat, and being very flexible it has a distinct advantage. 
It has been stated, although the author has not tried this, 
that for priming new wood half corn oil and half linseed 
oil with sufficient drier and volatile solvent produce a 
priming coat to which a second coat of linseed oil paint 
will adhere perfectly. 

The physical and chemical constants of corn oil 
cannot be given exactly for the reason that samples var\- . 



2i6 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Its specific gravity will run from 0.920 to 0.926; its 
saponification value will average 190; and its iodine 
value will average 120, although several samples exam- 
ined by the author have shown as high an iodine value 
as I. so. 



CHAPTER XVII 
Turpentine 

Turpentine occupies the same relative position among 
the vehicles of paints and varnishes as white lead does 
among the pigments. It is impossible to say for how 
many generations turpentine was the only solvent or 
diluent known to the paint and varnish industry, and 
therefore when other solvents were introduced they were 
looked upon as adulterants. 

The methods used in the manufacture of turpentine 
are very well known; the sap of the Georgia pine and 
two or three other species of pine trees growing in 
the southern part of the United States is collected 
and distilled with steam. The distillate is known as 
turpentine, and that which remains behind in the still 
is known as rosin (colophony). American turpentine 
has a very pleasant odor, and from several combus- 
tion analyses made by the author, the composition 
of turpentine taken directly from the barrel as shipped 
from the South corresponds absolutely with the theo- 
retical formida C10H16. It has absolutely none of the 
qualities of a paint preservative, but is used only to 
increase the spreading power and working quality of 
paint. Entirely too much stress is laid upon the value of 
turpentine as a paint vehicle, and the sooner the chem- 
ist and the consumer realize that turpentine is simply 
an auxiliary, the sooner will better substitutes be used. 

If the forestry department of this government will not 
interfere with the destruction of the trees, turpentine will 
become a chemical curiosity within the lifetime of many 

of us, unless new trees are planted. 

217 



2l8 CHEMISTRY AND TECHNOLOGY OF PAINTS 

American differs from Russian turpentine in odor and 
in specific gravity, although in chemical composition they 
are alike. The specific gra\4ty of American turp)entine 
is about .865 when fresh, but it will rise as high as .90 
when old. It is supposed to boil at 350° F., but that also 
depends very largely on the condition of the turj>entine 
and whether it has been exposed to the air. Turpentine 
flashes according to the text-books, and according to the 
majority of specifications that are written, at 105° F. 
As a matter of fact, its flash point is 98° F. Turpentine 
evaporates very slowly, and on account of this slow 
evaporation it is very highly prized as a varnish diluent, 
but there are paraffin products that have lately been 
invented that evaporate just as slowly and leave no resi- 
due behind. Pure turpentine when poured on a sheet 
of filter paper should leave absolutely no residue behind, 
and a drop of water poured on the paper after the tur- 
pentine has evaporated must be absorbed as readily by 
the paper as before it was immersed. In this regard the 
petroleum naphtha solvents are identical. They will be 
described in the proper chapter. 

The following organic analyses of French, American, 
and wood turpentines show that French turpentine and 
American tuq^entine are both represented by the for- 
nuihi C10H16, the American turpentine being practically 
100 i^er cent pure. Wood turpentine, however, may be 
shown to be 97.7 pure, the 2^ per cent of impurities con- 
sisting of pyridene bases, formalin, and other wood 
(lcr()m])()sition products. Since these investigations were 
made in 1905, samples of wood turpentine have been 
placed on the market which are so nearly identical with 
the sap turpentine that it is almost impossible to dis- 
tinguish them, only an experienced consumer being able 
to tell the (lilTerence, the wood turpentine having a pe- 



TURPENTINE 



219 



culiar odor which is lacking in the sap turpentine. No 
matter how thoroughly a wood turpentine is purified, 
there is always a smell of sawdust which clings to it and 
which can be recognized by a person once familiar with 
the odor. These pure grades of wood turpentine cannot 
be said to be adulterants of the sap turpentine. 



French Turpentine 

First Analysis 

Weight of sample o. 2040 grams. 

CO2 obtained 0.6558 grams. 

H2O obtained o. 2161 grams. 

Hence, percentage comp)osition, 

Carbon 87 . 67 per cent. 

Hydrogen 1 1 . 87 per cent. 

Total 99-54 per cent. 

American Turpentine 

First Analysis 

Weight of sample o. 1777 grams. 

CO2 obtained o- 57^4 grams. 

H2O obtained o. 1923 grams. 

Hence, percentage composition, 

Carbon 87 . 70 per cent. 

Hydrogen 12.12 per cent. 

Total 99 . 82 per cent. 

Wood Turpentine 

First Analysts 

Weight of sample o. 1891 grams. 

CO2 obtained o- 59v39 grams. 

H2O obtained o. 2042 grams. 

Hence, percentage composition. 

Carbon 85 . 65 per cent. 

Hydrogen 12 . 10 per cent. 

Oxygen 2.25 per cent. 

Total 100.00 per cent. 



Second Analysis 
o. 1870 grams. 
0.6009 grams. 
0.1980 grams. 

87 . 63 per cent. 
11.87 per cent. 

99 . 50 per cent. 



Second Analysis 
o. 1828 grams. 
0.5878 grams. 
0.1968 grams. 

87 . 69 per cent. 
12.07 percent. 

99 . 76 per cent. 



Second Analysis 
0.1656 grams. 
0.5202 grams. 
0.1785 grams. 

85.67 per cent. 

12.08 per cent. 

2.25 per cent. 

100.00 per cent. 



220 CHEMISTRY ASD TECHXOWCT OF PAIXTS 

In the Journal of the American Cbemkal Society^ 
for 1904 a very exhaustive treatise is given cm ^irits of 
turf)entine, in which it is demonstrated that the only 
reliable chemical test for differentiating between wood 
turpentine and the old spirits is the determination of the 
iodine absorption number. But even this is now growing 
to be very unreliable, for the reason that so much care 
and skill is exercised in the manufacture of wood tur- 
pentine that it is almost impossible to distinguish it 
from the sap turpentine. A great deal has been written on 
the optical activity of turpentine when obser\-ed through 
the polariscope. The paint chemist, however, cannot 
point with any degree of certainty to this test, excepting 
where a coarse mixture of benzine, rosin oil, etc., is made, 
and up to the present writing very highly refined tur- 
pintine and sap turpentines show little or no difference. 
'Hie admixture of rosin oil, benzine, benzene, kerosene, 
and adulterants of that kind are, of course, differentiated 
with more or less ease. 

'turpentine is by no means used as largely as it was 
pri<»r lo 1906. The reason for this, strange to say, is a 
I Mora I one and not a physical one. Ten years ago it 
would have been thought impossible to do without spirits 
ol lur|)entine in paint or varnish. Today it is used by 
iMiiny |)ro|)le who think they have to use it, and by others 
who use it in hi^h grade piano and other finishing varnishes, 
l)r< iuiM' Ihcy believe it gives a physical flow to the varnish 
which cannot he ()l)tained by the use of anything else. 
This, however, is (Hsputed by many manufacturers. At 
aM\ rale, the fact remains that several years ago turpentine 
lose Irnm a |)riee of about 40 cents per gallon to Si. 13, 
lor a number of men in the southern part of the United 
Stales attempted to corner the market. Before, how- 

' " Analysis of Turpentine," by Jno. M. McCandless, p. 981, 1904. 



TURPENTINE 221 

ever, the price reached the abnormal figure of $1.13 some 
of the officials of the United States Navy made exhaust- 
ive experiments and showed that the turpentine sub- 
stitutes of the petroleum type were absolutely as good 
and served the same purpose as spirits of turpentine. 
Not to go into the details of this, about five years ago 
the United States Navy substituted some 70,000 gallons 
of turpentine by turpentine substitute, and the resulting 
paint gave just as good service and the saving in price 
was very great. The men who had attempted to corner 
the market and enrich themselves at the expense of others 
were finally ruined, and the whole turpentine industry 
received a staggering blow, from which at this date it 
has not entirely recovered. The price dropped until it 
hovered around 40 and 50 cents, but in the meantime 
the paint industry had learned the lesson, which was of 
tremendous value, that it could do without turpentine 
entirely. 

Turpentine ^ 

Distillation of Pure Gum Spirits of Turpentine 
Will not begin distilling lower than 153° C. 



I to 2% distilk 


over 


by 


153° c. 


50% 


fi 


li 


ii 


157° c. 


80% 


ii 


a 


ii 


159° c. 


85% 


H 


a 


a 


160° c. 


95% 


U 


a 


<( 


165.5° c. 


Sometimes 










50% 


n 


ii 


u 


150° ^^ 


80% 


ii 


a 


ii 


160° c. 


85% 


li 


a 


a 


161° c. 



95% should be distilled by 165.5° C. 
^ Data from J. E. Teeple, Xew York City. 



222 CHEMISTRY ASD TECHXOLOGY OF PAISTS 

Distillation of Steam Distilled Wood Turpeniine 

Usually begins distilling at about 153® C. 

50% distills over by 160° C. 
80% " " " 164° C. 
85% " " " 165.5° c. 

95% " " " 175° C. 

Sometimes 

80% " " " 163° C. 

85% " " " 164° C. 

90/0 105-5 ^• 

95/0 172 C 

This hiltcr would be considered a very good grade. 

Sometimes oply 60% to 70% will distill by 165.5° C- — Poor 
Kradc. 

Wood Turpentine 

The turpentine in the United States is held in such 
strong hands that the price is abnormally high, and within 
the* last five years pine, sawdust, shavings, tree stumps, 
and old logs have been placed in retorts and distilled 
in the sanu* manner as the sap of the pine tree. A liquid 
is obtained which is sold under the name of wood tur- 
|)cntint' and is guaranteed by many to be absolutely the 
sa nu* material as that obtained from the sap of the 
Ircr. it must l)c frankly admitted that there are some 
wood 1 11 rjuMi tines on the market at this writing which 
an- so similar to tlie real article that it is almost impos- 
sible to (lilTerentiate between them. And yet there is 
always a |)eiuliar distinctive odor to these wood tur- 
pfhlinis wliicli docs not exist in the pure turpentines. 
Scx'cral organic analyses of this variety of wood tur- 
pentine l)v the author have shown that the formula 
is not ('lollhi, but that it is a most complex mixture con- 
taining more than a trace of pyridene bases, formic acid. 



TURPENTINE 223 

formaldehyde, and other products from the destructive 
distillation of wood. But wood turpentine is being 
improved so continually that these impurities are being 
largely removed. For exterior painting, wood turpen- 
tine that contains only a trace of these impurities is 
just as good as the sap turpentine, and for indoor paint- 
ing it is no better than a number of the petroleum 
products and costs very much more money. It cannot 
be said that it has advantages in exterior painting over 
the benzine products. One reason why it can be used on 
exterior work and not on interior work is that the dis- 
agreeable odor it sometimes gives off becomes obnoxious 
to those who use it on interior work. The pure grades 
of wood turpentine cost within 5 cents per gallon of the 
price of sap turpentine, and judging from the large 
number of concerns that have sprung up within the last 
five years for the manufacture of wood turpentine and 
then slowly disappeared, it is reasonable to infer that the 
industry is not profitable. 

AMERICAN SOCIETY FOR TESTING MATERIALS, PHILADELPHIA, 

PA., U.S.A., AFFILIATED WITH THE INTERNATIONAL 

ASSOCIATION FOR TESTING MATERIALS 

Standard SPEancATioNS for Turpentine 

Serial Designation: D 13-15 

The specifications for this material are issued under the fixed 
designation D 13; the final number indicates the year of original 
issue, or in the case of revision, the year of last revision. Adopted, 
1915. 

General. — i. These specifications apply both to the turpentine 
that is distilled from pine oleoresins, and commonly known as *'gum 
turpentine" or "spirits turpentine," and to the turpentine commonly 
known as "wood turpentine" that is obtained from resinous wood, 
whether by extraction with volatile solvents, or by steam, or by de- 
structive distillation. 



224 CHEMISTRY AND TECHNOLOGY OF PAINTS 

2. The purchaser, when ordering under these ^>ecificatioiiSy may 
specify whether gum spirits or wood turpentine is desired. 

The turpentine shall be clear and free from suspended matta: 
and water. 

Color, — 3. The color shall be ^^Standard" * or better. 

Specific Gravity, — 4. The specific gravity shall be not less than 
0.862 nor more than 0.872 at 15.5° C. 

Refractive Index, — 5. The refractive index at 15.5° C. shall be 
not less than 1.468 nor more than 1.478. 

Initial Boiling Point, — 6. The initial boiling point shall be not 
less than 150° nor more than 160^ C. 

Distillation, — 7. Ninety per cent of the turpentine shall distill 
below 170° C. 

Polymerization. — 8. The polymerization residue shall not ex- 
ceed 2 per cent and its refractive index at 15.5^ C. shall not be less 
than 1.500. 

Methods of Analysis 

9. Color, — Fill a 200-mm., perfectly flat bottom colorimetric 
tube graduated in hiillimeters to a depth of from 40 to 50 mm. with 
the turi)entine to be examined. Place the tube in a colorimeter and 
place on or under it a No. 2 yellow Lovibond glass. Over or under a 
second graduated tube in the colorimeter, place a No. i yellow Lo\i- 
lK)n(l glass and run in the same turpentine until the color matches as 
nearly as possible the color in the first tube. Read the difference 
ill (Iq)th of the tuq)entine in the two tubes. If this difference is 50 
mm. or more, the turpentine is "Standard'^ or better. 

10. Specific Gravity. — Determine specific gravity at any con- 
venient temperature with a plummet, the displacement of which has 
been accunitely determined for that temperature, or by an equally 
accurate method, usin^ the factor 0.00082 for each degree centigrade 
that the temperature of determination difTers from 15.5° C. 

11. Refractive Index. — Determine refractive index at any con- 
venient temperature with an accurate instrument, and calculate the 
results to 15.5° C, usinj; the factor 0.00045 for each degree that the 
temperature of determination dilTers from 15.5° C. 

' The term ''Standard" refers to the color recognized as standard 
by the '* \aval Stores Trade." Turpentine is of '* Standard" color 
when a depth of 50 mm. in a perfectly flat polished bottom tul>c 
approximately matches a Xo. i yellow Lovibond glass. 



TURPENTINE 225 

12. Distillation. — Use an ordinary Engler flask and condenser/ 
and heat the flask by placing it in a glycerin or oil bath of the general 
t\T)e described in Bulletin No. 135, Bureau of Chemistry. Fit the 
flask with a thermometer reading from 145° to 200° C. in such a way 
that the mercury bulb shall be opposite the side tube of the flask 
and the 175° mark below the cork. Place 100 cc. of the turpentine 
to be examined in the flask, connect with the condenser, insert stopper 
bearing thermometer, and heat until distillation of the turpentine 
begins. Conduct the distillation so that the distillate passes over 
at the rate of 2 drops per second. Note the initial distilling tempera- 
ture and the percentage distilling below 170° C. 

13. Polymerization, — Place 20 cc. of exactly 38 N (100.92 per 
cent) sulphuric acid in a graduated, narrow-neck Babcock flask, stop- 
pered, and place in ice water and cool. Add slowly 5 cc. of the tur- 
pentine to be tested. Gradually mix the contents, cooling from time 
to time, and not allowing the temperature to rise above about 60° C. 
When the mixture no longer warms up on shaking, agitate thoroughly 
and place the bottle in a water bath and heat from 60° to 65° C. for 
about 10 minutes, keeping the contents of the flask thoroughly mixed 
by vigorous shaking five or six times during the period. Do not 
stopper the flask after the turpentine has been added, as it may 
explode. Cool to room temperature, fill the flask with concentrated 
sulphuric acid until the tmpolymerized oil rises into the graduated 
neck. Centrifuge at about 1200 r. p. m. from 4 to 5 minutes, or allow 
to stand for 12 hours. Read unpolymerized residue, notice its con- 
sistency and color, and determine its refractive index. 

NAVY DEPARTMENT SPECIFICATIONS 

Turpentine 

General Characteristics, — i. The turpentine must be either a 
properly prepared distillate of oleo-resinous exudation of the proper 
kinds of pine, unmixed with any other substance, with the character- 
istic sweet odor of gum turpentine, or it must be pure wood spirits 
of turpentine, refined, and freed from heavy oils and empyreumatic 
or pyroligneous odors by steam distillation; both of the above shall 
be clear and water-white. 

Specific Gravity, — 2. The specific gravity shall not be below 
0.862 or above 0.872 at 15.5° C. 

^ Stillman, "Engineering Chemistry," p. 503. 



2 26 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Refractive Index, — 3. The refractive index shall not be less than 
1.468 nor greater than 1.476 at 20° C. 

Boiling Point, — 4. The boiling point shall be between 152® C. 
and 158° C. 

Distillation Test, — 5. When 200 ex. of the turpentine is dis- 
tilled, 95 per cent should pass over below 170® C. 

For this test use a 300 c.c. flask, 8 cm. in diameter, with a side 
tube 8 cm. from the main bulb, and the neck extending 8 cm. above 
the side tube. The neck is 2 cm. in diameter and the side tube is 
5 m. m. This flask should be fitted with a thermometer (reading 
from 145° to 200° C.) immersed in the vapor. The mercury bulb 
should be opposite the side tube of the flask and the reading 1 75** C. 
should be below the cork. The distillation should be so conducted 
that there shall pass over about two dropS/ of the distillate per second. 

Polymerization, — 6. When 5 c.c. of the sample is treated with 
sulphuric acid of specific gravity 1.84, according to the method herein 
outlined, there shall remain undissolved at the end of thirty minutes 
not over 0.09 c.c. The residue unpolymerized should show a refrac- 
tion value between 1.50 to 1.52. It should be viscous in nature. If 
the residue is water-white, limpid, and does not show proper refrac- 
tion value, it should be carefully polymerized with 38 N sulphuric 
acid according to Veitch (see p. 30, Bull. 135, or Cir. 85, Bureau of 
Chemistry, U. S. Department of Agriculture). 

Method of Polymerization. — 7. Add slowly 5 c.c. of the turpen- 
tine to 25 c.c. sulphuric acid, 1.84, contained in an ordinary graduated 
narrow-necked Babcock flask. Shake the flask with a rotarv motion 
to insure gradual mixing. Cool, if necessar\', in ice water, not per- 
mitting the temperature to rise above 60° to 65° C. Agitate thor- 
oughly and maintain at about 65°, with frequent agitations, for one 
hour. Cool. Fill the flask with H2SO4, bringing the unpolymerized 
oil into the graduated neck. Allow to stand one hour. Read off 
unpolymerized content, note its consistency and color, and determine 
its refractive index. 

Color Test. — S. Shake 10 c.c. of the turpentine with 10 c.c. of 
concentrated hydrochloric acid in a test tube. The development, 
after three minutes' standing, of a decided red color is indicative of 
the presence of other usually heavy resinous oils. 

Evaporation Test. — 9. When 10 c.c. of the sample are placed in 
a glass crystallizing dish, 2^ inches in diameter and i\ inches high, 
and evaporated on an open steam bath, with a full head of steam, for 



TURPENTINE 227 

three hours, the amount of residue shall not weigh more than 0.15 
gram. A single drop allowed to fall on clean white paper must com- 
pletely evaporate at a temperature of 20° C. without leaving a stain. 

Flash Point. — 10. The turpentine must not flash below 34° C. in 
Abel's enclosed tester. 

II. Bidders must state specifically on proposals whether they 
propose to furnish steam distilled wood turpentine or pure gum 
spirits of turpentine. 



CHAPTER XVIII 

Pine Oil^ 

One of the industries which has developed as a result 
of the policy of conservation in the United States is the 
manufacture of useful products from resinous woods. 
Enormous quantities of the latter, which in previous 
years were considered of little or no use and were deliber- 
ately burned in huge burners especially constructed for 
the purpose, or which were simply allowed to go to waste, 
are now being economically and profitably manipulated 
for the recovery of turpentine, pine oil, and rosin, or the 
production of tar oils, pine pitch, and charcoal. 

The two commercially important methods in vogue 
are, first, the steam and solvent or extraction process, and 
second, the destructive distillation process. 

H. T. Yar\'an2 has taken out letters patent on a 
process for extracting turpentine and rosin from resinous 
woods, which very well illustrates the extraction method 
as practised today. Resinous wood, reduced to fine 
cliii)s by passing through a wood chipper, is charged into 
an iron vessel through a charging door at the top. The 
wood rests upon a false bottom over a coil supplied with 
superheated steam for producing and maintaining the 

^ Journal of Society of Chemical Industry, June 15, 1914, No. 11, Vol. 
xxxiii, by Maximilian Toch. 

- The followinj^ is a list of the Varyan U. S. Patents: 

No. Qi 5,400, March 16, 1909 934,257, September 14, 1909 

015.401, March 16, 1909 964,728. July 19, 1910 

915.402, March lO, 1909 992.325, May 16, 1911 
922,369. May 18, 1909 

228 



PINE OIL 229 

proper temperature within the iron chamber. The door 
at the top and the discharge door at the bottom are 
closed, and the current of superheated steam is driven 
into the mass of chips. This is continued until the more 
volatile turpentine has been vaporized and driven over 
into the condensers. The wood in the extraction vessel 
is left charged with a small percentage of heavy turpen- 
tine, together with pine oil and rosin. Steam is shut off, 
the excess moisture in the hot wood is removed by 
connecting the vessel with a vacuum pump, and finally 
a liquid hydrocarbon (boiling point, 240^-270° F.) is 
sprayed over the top and allowed to percolate down 
through the pores of the wood. The resinous materials 
are thus thoroughly and completely extracted, and passed 
into a storage tank, from which they are pumped into a 
still used for separating the component parts of the solu- 
tion. From the still the hydrocarbon solvent is readily 
separated from the heavier pine oils by distillation under 
reduced pressure, on account of the great difference in 
the boiling point between the pine oils and the hydro- 
carbon solvent, the former boiling between 350° and 370° F. 
The pine oils are in turn separated from the rosin by 
distillation with superheated steam. 

Other so-called "low temperature" processes deserve 
mention as possessing features of merit, although sufficient 
data does not appear to be available to show their true 
value when operated on a large commercial scale. The 
Hough process, for example, is to be considered essentially 
a preliminary treatment in the manufacture of paper 
pulp from resinous woods. Chipped wood is placed in a 
retort and subjected to the action of a dilute alkali. The 
rosins are saponified and the soap separated from the 
alkaline liquor by cooling and increasing the alkali con- 
centration to the desired degree. The rosin soap may be 



230 CHEMISTRY AND TECHNOLOGY OF PAINTS 

sold as such, or treated with acids for recovery of the 
rosin. The turpentine and pine oils are recovered either 
by preliminary treatment with steam or during the early 
stages of the cooking process. • 

It will be noted that in the low temperature processes 
the only products recovered are turpentine, pine oils, 
and rosins, the first two removed by the action of steam, 
either saturated or superheated, and the latter by extrac- 
tion by use of a neutral volatile solvent or a saponifying 
agent. The so-called "spent wood" may be used either 
for the manufacture of paper pulp or as a fuel to generate 
the power necessary to carry out the process. 

In the destructive distillation process, the wood, in the 
form of cordwood 4 ft. to 6 ft. in length and 4 in. to 8 in. 
in diameter, is placed in a horizontal retort and the tem- 
perature gradually raised until the wood is thoroughly 
carbonized. The factor of greatest importance in the 
successful operation of this process is temperature control, 
as it is essential that the turpentines and pine oils be 
removed in so far as is possible before the temperature at 
which the rosins and wood fibre begin to decompose is 
reached. The total volume of distillate, as well as the 
percentage volume of each of the several fractions thereof, 
is largely dependent on the degree of temperature control. 

Destructive distillation of resinous wood was first 
carried out in earthen trenches, the combustion being 
controlled by partially covering the wood with earth. 
Tar and charcoal were the only products recovered. 
Then came the beehive oven, operated in much the same 
crude manner, but recovering the more volatile distillates, 
in addition to tar and charcoal. This was in turn super- 
seded bv the horizontal retort, externallv heated, hot 
gases being circulated either through an outer shell or 
through pipes within the retort. Next came the bath 



PINE OIL 231 

process, wherein the cordwood was immersed in a bath of 
hot pitch or rosin, thereby volatilizing the turpentine and 
lighter pine oils and dissolving the heavier oils and rosins. 
After this preliminary treatment the bath was withdrawn 
and the wood subjected to straight destructive distillation. 

More recently ^ a retort has been devised utilizing the 
basic principle of the laboratory oil bath. The retort is 
heated by means of a layer of hot petroleum oil which is 
kept continually circulating between the retorts and an 
outer cylindrical shell that completely surrounds the re- 
tort proper. In this way it is claimed that the tempera- 
ture of distillation can be accurately controlled. The 
turpentine and pine oil obtained are fractionated and 
rectified by subsequent steam distillation. In running the 
retort the temperature of the oil bath is so regulated that 
the heat inside does not exceed 450° F. before all the 
turpentine and pine oil have been distilled. 

The products of destructive distillation by the several 
processes are in each case of very much the same general 
nature, namely, turpentine, pine oils, tar oils, pine tar, 
pitch, and charcoal. In some instances low-grade rosin 
oils are also produced. 

"Light wood" does not refer to woody fibre which 
has a low specific gravity. The name originated from 
the fact that this particular wood is so rich in oil and 
resinous material that it is readily used for lighting fires. 
In the southern portion of the United States little bundles 
of *4ight wood" are for sale in strips about \ inch in 
diameter and i foot long. When a flame is applied to 
one of these strips of wood it becomes useful for lighting 
fires, hence the name "light wood." The author has seen 
"light wood" so rich in resins and oily material that by 
transmitted light a thin section looked like translucent 

^ T. W. Pritchard, Journal of Society of Chemical Industry, 191 2, 31, 418. 



232 CHEMISTRY AND TECHNOLOGY OF PAINTS 

ruby glass. It is this particular wood which is most 
used for the distillation of wood turpentine, pine oil, and 
rosin. 

The product from that type of pine tree from which 
turpentine is obtained has always been regarded as pro- 
ducing two materials when the sap has been collected and 
distilled. The one material is turpentine, and the other 
rosin. About ten years ago, when destructive and steam 
distillation of pine wood became a practical industry, a third 
substance was recovered. This material, intermediate be- 
tween turpentine and rosin, is now known as "pine oil." 

As far as the author knows, no one has yet determined 
the chemical constitution of this intermediate product of 
the pine tree, which has been designated as "pine oil." 
Two years ago the writer started this investigation, which 
is practically finished. There is as yet no standard of 
purity for pine oil, but that it has a definite chemical 
composition is now fairly well established. The only 
original investigation of the chemical composition of pine 
oil was carried out by Dr. J. E. Teeple^ on long leaf 
pine oil. 

Dr. Teeple says: "The commercial long leaf oil, as 
it comes on the market, is either clear and water white, 
containing 3 or 4 per cent of dissolved water, or it may 
have a very faint yellow color and be free from dissolved 
water. The specific gravity ranges from 0.935 ^^ 0.947, 
dq)cnding on freedom from lower boiling terpenes. A 
good commercial product will begin distilling at about 
206° to 210°, and 75 per cent of it will distill between the 
limits 2ii°-2i8° and 50 per cent of it between 213^-217°. 
A sample having a density of 0.945 at 15.5° showed a 
specific rotation of about \^a'] -J' — 11°, and an index of 

' Journal of American Chemical Society, 1908, 30,412; Journal of Society 
of Chemical lndustr>', 1908, 346. 



PINE OIL 233 

refraction of Np 1.4830. In fractional distillation of the 
oil the specific gravity of the various distillates rises 
regularly with increasing temperature, becoming steady 
at about 0.947 at 217°. 

"If the oil consists essentially of terpineol, CioHisO, 
it should be easy to convert it into terpin hydrate, 
C10H20O2 + H2O, by the method of Tiemann and Schmidt.^ 
The conversion was found to proceed easily when the oil 
was treated with 5 per cent sulphuric acid, either with 
or without admixture with benzine. If agitated contin- 
uously, the reaction is complete within 3 or 4 days. If, 
on the other hand, the mixture is allowed to stand 
quietly, the formation of terpin hydrate extends over 
several months and produces most beautiful large crystals, 
which, without recrystaUizing, melt at 11 7^-1 18°. When 
recrystallized from ethyl acetate they melt at 118°. The 
yield is about 60 per cent of the theoretical. This 
forms such a simple, cheap, and convenient method of 
making terpin hydrate that it will doubtless supersede 
the usual manufacture from turpentine, alcohol, and 
nitric acid, and instead of terpin hydrate serving as raw 
material for the manufacture of terpineol, as heretofore, 
the reverse will be the case." 

The term "pine oil," as now understood, is the heavy 
oil obtained from the fractionation of crude steam dis- 
tilled wood turpentine. When the sap of the pine tree 
is subjected to distillation in a current of steam the 
volatile liquid — turpentine — consists almost entirely of 
the hydrocarbon, pinene (CloHie). When, however, the 
trunk, stumps, and roots of the same tree have been 
allow^ed to remain on the ground for a number of years 
and are then steam distilled, there are obtained, in addition 
to th'e turpentine and rosin, certain heavier oils formed 

1 Bcr., 28, 1 781. 



fJT- -.r t : .• 



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dehydrating the material is necessary with temperature 
control, but the test which the author has devised for 
the determination of water is quite simple. If 5 c.c. of 
pine oil are mixed 
with I c.c. of a neu- 
tral mineral oil, like 
benzine, kerosene, or 
benzol, and a per- 
fectly clear solution 
is obtained on shak- 
ing, no water is pres- 
ent; but if there is 
any water present in 
the pine oil the water 
appears as a colloid, 
and a milky solution 
is obtained which ™ °™ ™ "" '"" '" ^ 

J * ,. Fifi- VI. 

does not separate 

after long standing. The fact that pine oil will take up 
a considerable quantity of water and still remain clear 
makes it useful for emulsion paints such as are very much 
in vogue at the present time for the interior of build- 
ings, and it has been suggested that the addition of water 
up to 5 per cent for such a purpose is beneficial on 
new walls. The United States Bureau of Chemistry • has 
developed a method for the determination of moisture 
by the use of calcium carbide; this is being investigated 
by the author but on account of its being a gas-volu- 
metric method it is not quite feasible for general use in 
technical laboratories. 

.\ number of commercial samples of pine oil were de- 
hydrated and analyzed. The tables following indicate 
the results obtained: — 
■ U. S. Dept. Agricuitur 



, Bure^ku of Chemistr)'. Circular 9 



236 



CHEMISTRY AND TECHNOLOGY OF PAINTS 







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PINE OIL 



237 



Table II. — Fractional Distillation of Commercial Pine Oil 



Temperature 



Water, 100® 
174— 194. . 
104 — 205. 
205 — 208. . 
208 — 210. . 
210 — 213. . 
213 — 216. . 
216 — 218. . 
218 — 




Total 
distillate 


Sp.gr. 

15.5° c. 


2 


0.882 


7 


0.920 


18 
28 


0.933 
0.939 


53 
88 


0.941 
0.942 


94 


0.942 


95 




99 





T.\ble III. — Ultimate .\nalysis of Pine Oil 



Sample Number. 



I 

2 

3 

4 

5 

() 

t 

8 

9 

.VvcraRc 

Teri)ine<)l (theoretical) 

French turpentine 

.American turpentine 

WVmkI turpentine 

Pine oil, first runnings 

Distillate pine oil, 174 — 195° C 




O. 



10.4 


10.7 


II. Q 


7.6 


8.5 


9.6 


10.4 


8.9 


lO.t) 


9.8 



10.38 



2.2 

3-9 
6.0 



CHAPTER XIX 

Benzine 

The petroleum products are used very largely in the 
manufacture of all kinds of mixed paints, the principal 
one used being that known as "benzine." It belongs to 
the series of organic compounds having the general for- 
mula CnH2n + 2. Although it is frequently added to paint 
in its pure form as a diluent it is just as frequently added 
in the form of a liquid drier which is a solution of the 
original thickened drier in benzine. 

Within the past ten years benzine has been so made 
that its odor is not very apparent, and there is much 
discussion as to whether benzine is a detriment to paint 
or not. It is hardly necessary to touch upon the moral 
side of this question. If a man should order a paint 
made according to a given specification and free from 
benzine, or to contain only turpentine as a diluent, the 
addition of benzine would be a palpable fraud. It is, 
however, unnecessar\^ to discuss this point. The prin- 
cipal questions for discussion are, first, "Is a moderate 
amount of benzine harmful to paint?" Second, "How 
much benzine is permissible in paint?" 

Answering the second question first, as to how much 
benzine is permissible in paint, that depends entirely 
upon the paint. A thick, viscous, ropy paint which is 
so difficult to apply that it will not flow evenly is un- 
doubtedly improved by the addition of benzine. It would 
be just as much improved by the addition of turpentine; 

perhaps it would be improved most by the addition of 

238 



BENZINE 239 

kerosene, especially in the case of very quick drying 
paints, since kerosene evaporates more slowly than either 
benzine or turpentine. In the case of such dilution theory 
fails and only practice can dictate how much diluent 
can be added. In the case of a dipping paint where the 
even spreading of a linseed oil paint is desirable, and 
the sudden evaporation of the solvent helps to produce 
a uniform coat, benzine cannot be replaced by any other 
solvent. 

The argument that is held forth by many, that ben- 
zine is of no value in a structural iron paint for the 
reason that its rapidity of evaporation lowers the dew 
point, as then moisture is deposited as it evaporates, is a 
most fallacious argument, although in theory it is cor- 
rect. Turpentine will do exactly the same thing and so 
will any other solvent, depending entirely upon the 
hygroscopic condition of the atmosphere. If painting be 
done in an atmosphere where the humidity is high and 
the temperature near the dew point, it is always found that 
it makes very little difference what solvents are used, 
the condensation being apparent in any case. The 
metallic structure itself lowers the dew point so that 
the painting is being conducted on a film of invisible 
water, to the detriment of the paint and to the detriment 
of the metal. On the other hand a series of experi- 
ments made on this subject showed that where the dew 
point and the humidity are high, condensation easily 
occurs even though the percentage of moisture in the 
atmosphere is relatively small. (See "Causes of Rust in 
the Subway," Journal of the Society of Chemical Indus- 
try, 1905, No. 10, Vol. 24.) A great advantage is to be 
obtained by the moderate use of benzine, for in brushing 
on a quick-drying paint containing benzine the evapora- 
tion carries with it much of the moisture in the paint. 



240 CHEMISTRY AND TECHNOLOGY OF PAINTS 

The low price of benzine in America oflFers a great 
temptation for its unlimited use. In France and Ger- 
many, where the petroleum products are more expensive 
than they are in America, and more particularly in 
France, benzine is not regarded so much as an adulterant. 
However, the physical effects of benzine have been so 
thoroughly overcome since turpentine has reached such 
an abnormal price, that a number of most excellent 
brands have been placed on the market as substitutes, 
all of which are equal in physical characteristics to 
pure spirits of turpentine. The objection, of course, 
to kerosene as a diluent in paint is that it may carry 
a small percentage of paraffin oil that has a tendency to 
produce a "bloom" on paint and particularly on varnish. 

Quite a large number of petroleum products have 
been placed on the market which are so closely analogous 
to turpentine that were it not for the odor, or lack of 
odor, it would be very difficult to differentiate them. As 
an instance it may be cited that turpentine is a better 
solvent for some of the mixing varnishes and fossil and 
semi-fossil resin driers than benzine, but the newer 
petroleum or paraffin compounds, some of which have had 
marked success, are absolutely identical in solvent power, 
speed of evaporation, and viscosity, to turpentine, and 
while the polymerization acid test would clearly show that 
they are not turpentine, they can by no means be said to be 
inferior in working quality or solvent power to turpentine. 
The method bv which these benzines are made consists 
in passing certain paraffin oils over red-hot coke in con- 
junction with wood turpentine. The product which is 
obtained has little or no odor. Thick or \dscous paints, 
particularly the varnish and enamel paints, are so much 
improved by the addition of these materials that even an 
inexperienced painter will notice the free-flowing quali- 



BENZINE 241 

ties of the material to which these diluents have been 
added. 

The petroleum products used in the manufacture^ of 
paint are principally 62° benzine, which means benzine 
having a specific gravity of 62° Baumfi. Some of the 
other naphthas ranging from 71° to 88° are used, but 
these are so light and bring so much higher prices than 
the 62° that they are not used as much as the 62° naph- 
tha. The newer grades, however, which approach tur- 
pentine in physical characteristics, must be counted on as 
an important factor in paint on account of the extremely 
high price of turpentine, and the fact that it is strongly 
held in a few hands. On account of the decreasing amount 
of this product, substitutes must be recognized. After 
all, any solvent, whether it be benzine, turpentine, 
naphtha, benzol or acetone, is nothing but a solvent and 
evaporates completely, leaving the other vehicles to pro- 
tect the paint. Of course, too much solvent is a detri- 
ment to paint, no matter what kind it may be. 

Benzine^ 

Engler Distillation of Commercial ^^^ Naphtha 

Sp. Gr. (Westphal) 15.6° C 0.651 

Np25° 1.3695 

Temperature % Wt. Sp. Gr. 15 . 6° C. Np 25° 

50® 47.7 0.609 1-3605 

50° to 75° 29.2 0.65 1-3756 

75° to 100° 6.8 0.70 I 3930 

Residue 1.4 .... 1.4061 

Engler Distillation of Commercial 62° Naphtha 
Sp. Gr. (Westphal) 15.6^ o. 732 

Np 25"^ 1. 4106 

^ Richardson & Mackenzie, Amer. J. of Sc. XXIX, May, 1910. 



242 CHEMISTRY ASD TECHXOiJOCY OF PAIXTS 



Tcmf>erature 


^cWu 


Sp.t 


r* 3 

ljF. 20 20 


c. 


*>p2^ 


50' 


.... 










so; to 75' 


1.2 








I 3S3O 


75'^ lo 100^ 


20.0 




0.7029 




I 3956 


100'' to 125'' 


51 9 




7286 




I. 4061 


125" lo 150** 


24.6 




0.7462 




I. 4168 


Kcniiduc 


9.2 








I.42S2 



CHAPTER XX 

Turpentine Substitutes^ 

When coal is distilled in the dry form volatile hydro- 
carbon gases are liberated, which when condensed form a 
liquid which has great value in the arts, and is generally 
called crude benzol. Its composition really is about 60 
per cent of benzol, the balance being toluol, xylol and 
solvent naphtha. The latter three are homologues of 
benzol. It is estimated that over forty million gallons 
of these solvents have been wasted in the United States 
in smoke and vapor in the manufacture of coke, but at 
this writing great efforts are being made to collect the 
vapors economically and to put in additional ovens for 
the manufacture of these by-products, so that it is very 
likely that both benzol and toluol will soon be sold again 
at normal prices. At this writing both benzol and toluol 
have risen from 25 and 30 cents per gallon to $1.25 and 
$7.00 per gallon respectively, owing to the great European 
war and to the small amount of benzol and toluol manu- 
factured in the United States. These materials have 
been sought for very eagerly for the manufacture of both 
carbolic and picric acids and trinitrotoluol. 

Benzol 

This material was for many years known under the 
name of benzene, and here it must be noted that the 
benzene which is equivalent to benzol is always spelled 

^ In the chapter on "Turpentine" the author has related how 
turp)entine substitutes came into their own on account of the excessive 
price of turpentine. 

243 



244 CUEMISTRY ASD TECHXOWGV OF PAJXTS 

benzene, and the light naphtha obtamed from paraffin 
crude oil is spelled benzine. 

Benzol is the first volatile liquid which is recovered 
when coal tar is distilled. Benzol when pure is color- 
less has a pleasant odor, a specific gra\^ty of 0.879 and 
a boiling point of 191° F. It flashes practically at air 
temperature. It crystallizes into a solid at the freezing 
I)oint of water and has a peculiar analogy to water 
inasmuch as it melts again at about 37° F. It is insoluble 
in water but is soluble in alcohol, ether and petroleum 
nai)htha. Its formula is CeHc; it attacks, though it 
does not dissolve, all forms of linoxyn, which it wrinkles 
and removes from the base. It is for this reason that 
it is so valuable as a paint remover. 

Benzol has remarkable solvent properties for many 
things which contain water, such as a number of the 
soaps, and is therefore invaluable to the paint manu- 
facturer when used in small quantities, for it prevents the 
livcring or saponification of many of the paints which have 
alkaline tendencies, and which would become unfit for 
use if it were not for the small quantity of benzol 
added. 

The addition of benzol to mixed paints to be used 
for |)riining purposes has been found to be very advan- 
taj^eous, on account of the fact that a firmer bond is 
formed between a j^riming coat and the wood, so that 
when benzol is found in a mixed paint recommended for 
|)riiniiiK purposes it must be looked upon as a valuable 
ingredient. 

The addition of a ver\' small percentage of benzol to 
mixed i)aints does no harm, but if a paint made with 
hen/ol and intended as a priming coat be used as a 
linishing coat it is (juite likely to attack the ground coats 
and produce a shriveled cfTect. 



TURPENTINE SUBSTITUTES 245 

The theoretical chemist will sometimes make a mistake 
when he finds benzol in a black mixed paint by reporting 
the presence of coal tar, from the false reasoning that if 
benzol is present coal tar must be present, because benzol 
is a constituent of coal tar. A chemist must, therefore, 
be very careful in drawing such a conclusion, for the 
presence of either coal or pine tar in a paint can be 
determined by other methods. 



Toluol 

Formula, CeHsCHs 

Toluol is very closely related to benzol, has practically 
the same specific gravity but a trifle lower — .869 to .87 — 
a freezing point of 30° F., and a boiling point of 230°. 
It does not flash at air temperature, and therefore 
is of considerable value where high flash paints are 
wanted. 

In the manufacture of turpentine substitutes out of 
paraffin or petroleum naphthas the addition of toluol is 
of great value, particularly where refractory gums are 
to be dissolved. As for instance, cold petroleum naph- 
tha added to a manila varnish will practically throw it 
out or precipitate it out, whereas the addition of toluol 
prevents this, depending upon the amount of toluol that 
the solvent contains. 

It has been recommended, and from experiments made 
it appears to be a fact, that toluol added to a paint in a 
quantity not over 10 per cent is of great value in the 
painting of cypress wood, but it is doubtful whether it 
is any better than pine oil, which can be used more 
liberally and which has even more penetrative effects 
and a higher flash point than toluol. 



246 chemistry and technology of paints 

Xylol 

Formula, C6H4(CH3)2 

Xylol really consists of three isomers having boiling 
points of 278° and 287° respectively. It cannot be very 
well separated by distillation. Xylol has all the char- 
acteristics of toluol but is not used to any great extent 
in the paint industry on account of its high price. 

Solvent Naphtha 

This is a mixture of different hydrocarbon compounds 
which have not yet been very well worked out; but sol- 
vent naphtha has a very disagreeable odor, which no 
one has been able to remove up to the present time, and 
therefore its use in the paint industry is very limited. 
When someone will discover a method for deodorizing 
solvent naphtha it probably will replace many of our 
solvents, as it is really a better solvent than anything we 
know of at present, and even dissolves such materials 
as gutta percha, balatta and many forms of rubber. 
Its specific gravity is the same as that of xylol and toluol, 
but it boils at a much higher temperature, depending 
upon its composition, from 300° F. to 360°. 



CHAPTER XXI 

Cobalt Driers^ 

The cobalt compounds which are generally offered on 
the market today may be divided into two classes. In 
the first are cobaltous oxid, acetate, sulphate, • chloride, 
nitrate, hydroxid, and basic carbonate. In the second 
class are various grades and qualities of resinates (some- 
times called sylvinates), both fused and precipitated, 
oleates or linoleates, oleo-resinates, tungates and resino- 
tungates, besides some other liquid preparations com- 
posed in whole or part of the foregoing. 

From the varnish manufacturer's standpoint the 
substances in the first division are crude materials which 
are utilized in the production of the compounds in the 
second class, and also in the preparation of some var- 
nishes, liquid driers, drying oils, and the so-called paint 
oils. The materials enumerated under the second class 
are the result of a varnish maker's labor, and when 
properly made and used in mixtures to which they are 
adapted give very good results. 

The inorganic salts of cobalt do not directly come 
under the scope of this paper, and thus will not be 
directly considered except inasmuch as their use as crude 
material affects the driers into whose composition they 
enter. 

It is only within the past three years -that the cobalt 
driers have been offered to the American paint and varnish 

^ By V. P. Krauss, 8th Int. Congress of Applied Chem. From 
the laboratory of Toch Brothers, under the direction of the author. 

247 



248 CHEMISTRY AND TECHNOLOGY OF PAINTS 

manufacturers. Up to the present time their use is not 
general, first, because of the very high price, and second, 
because their use is not thoroughly understood. Many 
experimenters have had unsatisfactory results and there- 
fore refused to further consider the introduction of 
the new material. Furthermore, not all of the cobalt 
driers, whether liquid, paste, or solid, now offered for 
sale, are properly made and truly adapted to the pur- 
poses for which they are recommended. This situation, 
in addition to unsatisfactory results obtained by some 
of those experimenting, would naturally have a retarding 
effect on the introduction of a new type of material. 

The salts of cobalt which are at our disposal in com- 
mercial quantities are all of the cobaltous or divalent 
type. It has been found that although they can be 
readily used in the manufacture of driers and worked 
like the various compounds of manganese, lead, zinc, 
calcium, aluminium, etc., the organic compounds formed, 
which are the basis and active principles of the so-called 
driers, are not efficient while in the cobaltous state. 
The cobaltic combinations, however, are ver}' active 
driers, and it is for the formation of trivalent cobalt 
c()mi)ounds that we strive in the making of driers. This 
transformation can be effected in several ways. By blow- 
ing cold, heated, or ozonized air through the hot cobal- 
tous drier stock, or by the introduction of liquid or solid 
oxidi/in^ agents. The use of cold or even heated air is a 
\vvy long and tedious operation if carried out to the 
I'xlciit to which it is necessary' in order to get the maxi- 
nnini strcngtli in the drier, and greatly adds to the cost 
of an already expensive material. The use of the liquid 
or solid oxidizers can be carried out successfullv and in a 
comparatively short time, although even when great care is 
exercised the batch of material is in danger of catching fire. 



COBALT DRIERS 249 

Since driers are used in a number of industries in 
which drying oils form part of the material produced, 
and since the operating methods of the various manu- 
facturers are widely divergent, the siccatives or driers 
adapted to each will in many instances show widely 
different characteristics, not merely in form but also in 
composition. 

Since the paint manufacturer and also the practical 
painter who mixes his own paints from paste colors and 
raw or treated oil are the principal consumers of what 
are generally known as driers, the materials adapted for 
their use may be first considered. The driers will, in 
practically all instances, be in the liquid state either very 
fluid, of heavy consistency or of a semi-paste nature. 
In composition, they will mostly consist of resinates, 
tungates, oleates, or linoleates, or combinations of the 
three. For the drying of linseed oil, when the proper 
driers are selected, little or nothing can be asked in ad- 
dition to those known at present. When the general lead, 
manganese and other prevalent metallic driers are well 
chosen raw linseed oil can without any difficulty be made 
to dry by the addition of from 5 to 10 per cent or even 
less, the time of drying under average weather conditions 
being from 10 to 24 hours. By the use of cobalt driers, 
the same drying effect can be obtained when only from i 
to 3 per cent of a liquid drier is used. The author is not yet 
prepared to say positively what the ultimate effect of cobalt 
driers is upon paint films, but from the experiments made 
it is deduced that cobalt has not the harmful progressive 
oxidizing action that some of the usual manganese-lead 
compounds have. It has also been noticed that although 
a cobalt drier may be fairly dark in color, it will not have 
as darkening an effect as one of the usual driers of like 
color would have upon a white paint. The cobalt driers 



250 CHEMISTRY AND TECHNOLOGY OF PAINTS 

likewise show the same phenomena as some of the 
others when used in excessive amount; that is, that 
although the paint film will set up well in the usual time 
the drying action apparently reverses and the film remains 
tacky. 

The terms applied to liquid driers are often uncer- 
tain and apt to be misleading. There are no general 
standards for strength or consistency, and, it must be 
admitted, ma-ny of the materials found on the market 
contain more volatile thinners than is conducive to 
obtaining a maximum drying effect with a minimum 
quantity of drier. 

The value of the cobalt specialties depends not on 
their power to dry linseed oil, but on their ability to 
make the lower priced semi-drying oils act like it. 

Soya, fish, and even corn and cottonseed oil are 
adaptable for use in paint, and when correctly treated, 
increase its durability. 

In the making of waterproof fabrics, insulating coat- 
ings, etc., both liquid and solid driers are used. In the 
linoleum, oilcloth, patent leather, artificial leather and 
similar industries, the semi-liquid, paste, and solid driers 
arc in demand since for these products the manufactur- 
ers cook the oils and varnishes in their own factories. 

The paste and solid driers must essentially be con- 
sidered under the caption of crude materials because 
they must be churned or cooked in the oils or varnishes 
in which they are used. 

The methods of making both the solid and liquid 
driers are in general similar in the first stage of the 
process, and thus may be described under the same 
headings. 

Resinate of Cobalt; Precipitated and Fused, — This is 
correctly made by saponifying rosin or colophony with 



COBALT DRIERS 251 

caustic soda or sodium carbonate, care being taken to 
avoid an excess of the reagent, and then precipitating 
with a solution of some salt of cobalt. The chloride or 
sulphate serve best for this purpose. The precipitated 
resinate, or as it is sometinaes called, rosinate or sylvin- 
ate, must then be thoroughly washed, and then pressed 
and dried. This will yield a pinkish, fairly fluffy powder 
when ground, which will readily dissolve in oil at a low 
temperature. The fused variety is made by melting the 
dried resinate in a kettle and then pouring into cooling 
pans. The operation is performed more rapidly by 
taking the cakes from the presses and driving off the 
water and fusing in one operation. 

Cobalt Oleates or Linoleates. — The basis of this class 
is generally linseed oil, although walnut, perilla, soya, 
and some other oils may be used. The oil is thoroughly 
saponified with caustic soda, and, like the resinate, pre- 
cipitated with a salt of cobalt. The material is then 
carefully washed and pressed. It may be melted to form 
a dark viscous heavy fluid. 

Several samples of cobalt linoleate examined 
consisted of bodied linseed in which small amounts 
of inorganic cobalt salts had been dissolved. Another 
was of the same order with the addition of volatile 
solvents. 

True linoleate of cobalt, wheu fused with varnish 
gums and dissolved in volatile oils, yields an excellent 
drier. 

Oleo-resinates. — This type of drier is made by melting 
together the precipitated resinate and linoleate, some- 
times with the further addition of fused fossil gum- 
resins. 

Tungate of Cobalt. — Like the linoleates, the tungate 
of cobalt is made by saponifying pure China wood oil 



252 CHEMISTRY AND TECHNOLOGY OF PAINTS 

(tung oil) with caustic soda, care being taken to avoid 
excess of caustic,- and then precipitating with a salt of 
cobalt. The tungate is then washed thoroughly, pressed 
and generally dried and fused. Great care is necessary 
in the preparation of a tungate since it oxidizes very 
rapidly, and the oxidized material is useless. 

Like the linoleate of cobalt, the tungate may be fused 
with the resinate to form what may be called a resino- 
tungate. 

In general the foregoing substances are incorporated 
in oils by means of heat, the combining temperature be- 
ing between 300° and 500° F. The amount necessarj' will 
vary from about | per cent to 5 per cent. In order to make 
liquid drierSy the paste or solid driers can be melted alone 
or in combination with gum-resins, bodied linseed oil, or 
both, and then thinned to liquid consistency with volatile 
oils. 

Among other cobalt salts, some of the chemical manu- 
facturers offer the acetate, with directions for its use as a 
drier. All agree that between two and four tenths of i 
per cent are necessary to dry linseed oil. The oil should 
be at a temperature between 300° and 400° F., and be 
carefully stirred until all the salt is dissolved. Sova and 
China wood oil may be similarly manipulated. 

It is still a little too soon to make a positive state- 
ment as to how oils thus treated with the acetate with- 
stand wear and exposure. 

Cobalt oxide, like the acetate, can be directly added 
to oil (luring boiling. It, however, dissolves slowly and 
necessitates heating to high temperature; the resulting 
product is also very dark, and mostly consists only of 
bodied oil. Rosin also will directly combine with cobalt 
compounds on heating together in a suitable kettle or 
container. The product possesses a number of objec- 



COBALT DRIERS 253 

tionable features. It still is mostly unchanged rosin, 
has become much darker and lost considerably in weight 
due to volatilization. The effect on oils of quite a number 
of cobalt compounds was tried, but none equal in efficiency 
to those described in the foregoing was found. 



CHAPTER XXII 

\ 

I 

COMBINING MEDIUMS AND WATER 

Combining Mediums 

In certain classes of mixed paints, particularly house 
paints which are made of corroded lead, sublimed lead, 
barium sulphate, etc., there is a likelihood or tendency of 
the pigment to settle. This is more marked in the case 
of corroded lead than in any of the other pigments. To 
prevent this, in a measure, water is added, and up to a 
certain percentage (i per cent) both the manufacturer and 
the consumer have accepted the fact that water is not 
injurious when added for the purpose of combining the 
paint; but beyond this percentage its effect is likely to be 
injurious. 

Sometimes for the sake of an argument, but more 
often for the sake of making a paint which contains no 
more water than the natural moisture of its constituents, 
a manufacturer feels the necessity of adding a combining 
medium other than water to prevent the paint from 
settling hard in the package. Among these are gutta- 
percha solutions, solutions of balata, para-rubber, gum 
chicle, etc. The rubber solutions mentioned serve their 
I)urf)ose very well without injuring the paint, and the 
percentage used is so small that it may be considered 
negligible. This, however, is not true of many of the 
mixing varnishes which are made by varnish manufactur- 
ers who have no experience in the manufacture of paint. 

They sell rosin varnishes neutralized with lime, lead, or 

254 



COMBINING MEDIUMS AND WATER 255 

manganese, and while they assist very well in combining 
the lead with the oil, the wearing quality of the paint is 
proportionately reduced. 

Within the last few years a new combining medium 
has appeared on the market which in itself is an improve- 
ment on all paints. It is made by melting a mixture of 
a resin (free from rosin or colophony) and heavy linseed 
oil, and reducing with China wood oil and naphtha. 
Where a manufacturer uses a combining medium of this 
character the paint becomes more viscous as it grows 
older, and when it dries it produces a satin-like gloss and 
shows fewer brush marks than a paint containing water. 

Water in the Composition of Mixed Paints 

The question of how much water shall be added to 
mixed paints, or how much water mixed paints shall 
contain, either added or incidental, is not fully decided 
upon, as there is a difference of opinion as to its value, 
and likewise a difference of opinion as to the amount 
necessary for certain purposes. There are some paints in 
which 83 high as 2 per cent of water is necessary, and in 
other paints less than i per cent is purposely added. 
That water is of great benefit in certain paints cannot 
be disputed, one large railway corporation permitting 
the addition of i per cent of water to its mixed and 
paste paints. 

A chemist in making an examination of a mixed paint 
must necessarily be careful in giving an opinion as to the 
amount of water in the paint, and great judgment must 
be used in a report. For instance, a paint, made accord- 
ing to a certain specification, containing a large mixture 
of Venetian red and yellow ochre, might contain very 
nearly 2 per cent of moisture, which was a part of the 



256 CHEMISTRY AND TECHNOLOGY OF PAINTS 

composition of the pigment. Then again, linseed oil fre- 
quently contains more than a trace of water, which the 
manufacturer cannot extract nor can he afford the time 
necessary to allow the water to settle out of the oil. A 
mixed paint should not contain over i per cent of water, 
for it is unnecessary to add more than this amount to 
any paint. 

The proper benefits derived from the addition of water 
to a pure linseed oil paint are suspension of the pigment 
and improvement in its working quality. Take the case 
of artists' tube colors which lie on the dealers' shelves 
for years and which are prone to get hard and likely 
to separate so completely that the color will be found 
on one side of the tube and the oil be entirely free on the 
other. Water is an absolute necessity in this case and is 
an improvement for both seller and user. The colors 
made with the correct addition of water are known 
to "pile,'' and artists prefer a color which "piles" 
prop)erly. 

There are many ways of adding water to a paint. 
In some instances the required amount of water, together 
with the oil and the drier, are placed in a churn or mixer 
and the paste paint stirred in. WTiere materials like 
calcium sulphate, calcium carbonate, ochre, Venetian red, 
silicate of magnesia, silicate of alumina, white lead, etc., 
are used, there is no necessity for adding any combining 
material which will form a soap with the linseed oil, 
there being sufficient action between these materials and 
the water. It is an additional advantage that there is 
less likely to be complete saponification in a mixed paint 
to which no "emulsifier'' has been added. 

The following materials arc used for emulsifying 
j)aints: 



COMBINING MEDIUMS AND WATER 257 



Saturated solutions of hypochlorite of lime. 

Five per cent solution of carbonate of soda. 

One-quarter of one per cent solution caustic soda. 

One per cent solution of carbonate of potash. 

Emulsion mixtures of half water and half pine oil. 

Solutions of hypochlorite of lime containing twenty per cent 

wood alcohol. 
Ten per cent solution of borax. 
Five per cent solution zinc sulphate. 
Seven per cent solution \ead acetate. 
Five per cent solution manganese sulphate. 
Solutions of ordinary laundry soap or rosin soap in half 

alcohol and half water. 
Weak solutions of casein dissolved in ammonia water. 
Ordinary lime water emulsified with linseed oil. 



There is no license whatever for the addition of much 
water to paint. Some authorities state that as high as i| 
per cent is permissible, but the author does not by any 
means subscribe to that, as i| gallons of water in loo 
gallons of paint are far in excess of any desirable amount. 
Three-quarters of i per cent or at most i per cent 
would probably be a maximum, and as an explanation 
of this it must be understood that materials like ochre, 
clay, silicate of magnesia, white lead, calcium sulphate 
and many of the pigments which contain moisture or 
water of crystallization may carry a small amount of 
water into paint. 

Yet there may be cases where water is permissible up 
to 5 per cent, but only for interior purposes. Flat wall 
paints which have a tendency to settle hard can be 
emulsified so as to prevent them from settling, and in a 
case of this kind where the wear of the paint is not taken 
into consideration there may be some excuse or license 
for the addition of water. 



258 CHEMISTRY AND TECHyOLOGY OF PAIXTS 

To detect water in paint, particularly in light-colored 
paints, is a comparatively simple matter. The method 
devised by the author is almost quantitative for some 
purposes. The first method ever published by the 
author consisted in placing a strip of gelatin in a mixed 
paint. When a measured or weighed amount of mixed 
paint was taken and the strip of gelatin allowed to remain 
immersed for twenty-four hours a fairly correct quantita- 
tive determination was obtained. Another method de- 
scribed some years ago involved the use of anhydrous 
sulphate of copper, a bluish white powder, which on the 
addition of water returns to the natural dark blue color 
of crystallized copper sulphate. 

The author has, however, devised the scheme of 
using a glass plate and mixing a paint with a dyestuflf 
such as "Erythrosine B." When about ^ gram of the 
dye and 5 grams of mixed paint are rubbed together 
with a palette knife on a sheet of glass, a paint con- 
taining no water will produce a distinct pearl-gray color; 
if there is water in the paint the mixture changes almost 
immediately to a brilliant cerise red, and if there is much 
water in the paint (over 2 per cent) the color changes 
into a crimson, so that the reaction is clearly marked. 
The test must not be allowed to stand more than four 
minutes, since even paints which contain no added water 
but which naturally contain traces of moisture will begin 
to change into a rosy color, in which the presence cannot 
be rci)orted. In red, black or dark colored paints Er\'- 
throsine B is just as indicative of water in paint, par- 
ticularly when the mixture is viewed by transmitted light. 
Kvcn in the case of black paint the erythrosine emulsion 
j)aint will produce a beautiful purple color. 



CHAPTER XXIII 

Fiyit Grinding 

There is a great difference of opinion on the question 
of how paints should be ground, and a careful canvas on 
this subject reveals the fact that most paint manu- 
facturers believe that all paints should be very finely 
ground. This is a great error, for there are many con- 
ditions where a paint should be slightly coarse in order 
to give proper results, for if paints do not have a slight 
amount of coarseness, or "tooth'' as it is called, one coat 
will not hold successfully on the other, and it is for the 
very reason of producing a mechanical bond that fillers 
are used which have a distinct grain. Without making 
any general rule on the subject, all priming coats should 
have suflScient tooth to enable the succeeding coat to 
hold. 

Those familiar with the subject are aware of the 
fact that a gloss coat on a gloss coat very frequently 
peels, and the same is sometimes true of a gloss coat on a 
priming coat which is too finely ground. This does not 
apply to a finishing coat, because the finer a finishing 
coat the longer it lasts and the cleaner it remains, for a 
coarse finishing coat will hold dust and dirt which even a 
heavy rainstorm will not always dislodge, while a smooth, 
finely ground finishing coat acts like a glaze and remains 
clean until it perishes. It may therefore be taken as a 
general statement that priming coats should be slightly 
coarse and finishing coats should always be fine. 

259 



I 



26o CHEMISTRY AND TECHNOLOGY OF PAINTS 

If you take the case of the finishing of a very fine 
object like a piano or an automobile, rubbing varnishes 
are used on the undercoat, and these varnishes are 
scarified with pumice stone for two reasons: first, so as 
to smooth the coat thoroughly because the succeeding 
coat when applied will then itself produce a smooth and 
glossy effect, and secondly, so that the next coat which 
is applied can bind itself mechanically to the undercoat. 
If, therefore, rubbing is a practice where varnished objects 
are to be finished, it must be taken as a rule that where 
paints are applied and rubbing is not practiced a slight 
grain is of great benefit, so that the question of fine 
grinding does not apply to every case. 



CHAPTER XXIV 

The Influence of Sunlight on Paints and 

Varnishes^ • 

It may properly be said that direct sunlight has a 
vety destructive action on paint and varnish films, and 
the author had noted as far back as 15 years ago that 
many of the paint materials that were perfectly water- 
proof in places where sunlight never reached became 
permeable to water and disintegrated very rapidly when 
exposed to direct sunlight. As an example of this, it 
might be cited that pure asphaltum, when applied in a 
good continuous coat on cast iron pipes in a cellar, will 
last from three to four years, yet the same asphaltum 
when applied on the roof of a building will show al- 
most complete decomposition within 20 days. In order, 
therefore, to determine the cause, the first experiments 
with a series of bitumens were made as follows: Sheets 
of clean steel and wood were painted with a variety of 
bitumen compoimds and exposed to direct sunlight under 
various colored glasses, finally reduced to the three 
colors, violet, green, and red; for obvious reasons these 
three served all purposes. It was found at the end of 
four weeks that the bitumens exposed under the blue 
rays showed marked signs of decomposition, those under 
the green showed some signs, and those under the red 
none whatever. The same experiments were tried again 
by cementing the glass to the painted surface, when 
little or no decomposition followed in any case. A large 

^ Reprinted from the Journal of the Society of Chemical Industry', 
April 15, 1908. No. 7, Vol. XXVII, Maximilian Toch. 

261 



262 CHEMISTRY AND TECHNOLOGY OF PAINTS 

variety of experiments was then tried by mixing the 
bitumens with various pigments, and a preservative 
action was obtained in direct ratio to the pigment used, 
so much so that a sample of paint made to contain 80 
per cent of bitumen, 15 per cent of linseed oil, and 5 i>er 
cent of finely divided carbon, showed only slight deterio- 
ration at the end of six months; this was easily accounted 
for by the fact that the finely divided carbon prevented 
the absorption of many actinic rays. While these 
experiments were very conclusive, it was necessary to 
determine the cause, and to this end a large variety of 
experiments was conducted, all of which were productive 
of excellent results. 

All asphaltums are bitumens, but all bitumens are 
not asphaltums, and it is necessary to look into the com- 
position of the asphaltums which decompose in the sun- 
light and of those resins which do not. The difference 
between a resin and an asphaltic bitumen may generally 
be stated as follows: — Asphaltums and bitumens are 
composed principally of carbon and hydrogen, w^hereas 
the resins are semi-fossilized, and composed of carbon, 
hydrogen, and oxygen. Asphaltums, whether they be 
natural or artificial, consist largely of hydrocarbons of 
the series of CnHon-o, CnH>n-4, CnHjn-s, etc., and according 
to Clifford Richardson * and others, these hydrocarbons 
are i)robably polymethylenes. From a large number of 
combustion determinations made with bitumens, it may 
be safely stated that many of the bitumens are probably 
polymethylenes of various series, as above. There are, 
of course, substances in bitumens such as sulphur and 
nitrogen, which probably exert very little influence on 
the material from an actinic i)oint of view. Assuming, 

' St'c '* The Modern Asphalt Pavement " and * Origin of Asphalt/' 
1)V ClitTord Richardson. 



INFLUENCE OF SUNUGHT ON PAINTS AND VARNISHES 263 

therefore, that the hydrocarbons are of the character 
described, we should have under the combined action 
of the oxygen of the air and the actinic rays of the light, 
sometimes, in conjunction with moisture, a favorable 
condition where oxygen would combine with hydrogen, 
and carbon be set free. Therefore, if this reaction takes 
place, all bitumens in a short time ought to become car- 
bonized and deposit relatively pure carbon on their sur- 
faces, and this is exactly what takes place, the action of 
the sunlight probably resulting in a combination of the 
hydrogen with oxygen, and a deposit of what appears to 
be carbon takes place. If this, then, is the first lucid 
explanation of the decomposition of bitumens in sunlight, 
it is the explanation of the cause of the valuelessness of 
pure bitumens as protective paints for exterior purposes. 
Even the addition of a small amount of bitumen to a 
large percentage of otherwise good paint will result in the 
decomposition of this paint when exposed to the direct 
action of moisture and light. 

We have no such action when materials are used which 
are glycerides of fatty acids, such as fish oil, Chinese 
wood oil, and linseed oil. Indeed, any one of these three 
oils are light-proof in a very large degree, and fish oil 
and Chinese wood oil are both heat-proof and light-proof. 
Linseed oil, however, unless prepared with fossil resins, 
is not water-proof, but fish oil is more water-proof, and 
Chinese wood oil most water-proof of all. At the same 
time, pure Chinese wood oil is less light-proof, next comes 
fish oil, while linseed oil is most light-proof, and there 
would appear to be an established ratio that a paint or 
varnish containing the least amount of oxygen is the 
least light-proof and the most water-proof, and the paint 
containing the largest amount of oxygen is most proof 
against light, and least water-proof. 



264 CHEMISTRY AND TECHNOLOGY OF PAINTS 

In conclusion, and as evidence of the correctness of 
these statements, if a sheet of metal or wood be painted 
with asphaltum or bitumen-paint and exposed to sunlight 
and air, the coating will be rapidly decomposed, and after 
a lapse of 20 days probably carbon will be set free. 
At least, this is a deduction from the nature of the 
bitumens. Minute scrapings from the surface of exp)osed 
bitumens show that the principal constituent is carbon, 
and, whereas the original material contains much less, 
the exposed bitumen shows over 95 per cent of carbon, 
the remainder being principally hydrogen, with a small 
difference, which is evidently oxygen. This shows that 
the general reaction tends to produce carbon. 

The painting of concrete to preserve it against the 
action of moisture and frost is destined to become as large 
an industrj^ as the painting of wood, and those who have 
tried asphaltum paints for this purpose have already 
found to their sorrow that disintegration takes place in 
a very short time, even though the material be perfectly 
proof against the alkaline action of the lime in the con- 
crete, and as linseed oil paint is rapidly destroyed by 
concrete itself, owing to the interaction of the lime and 
the linseed oil, we have to look for other materials with 
which we can coat concrete in order to preserve not only 
its appearance, but the very structure itself. 

Regarding the action of sunlight on pigments, it is 
well known that lithopone is rapidly acted upon by light, 
and direct sunlight turns it a dark gray, but frequently 
overnight the color leaves it and it is brilliant white 
again in the morning. English vermilion (mercuric 
sulj)hide) is also acted upon by sunlight, and forms first 
a brown comi)ound and then a black compound of mer- 
cury. This has been regarded as mercurous sulphide or 
as a sub-suli)hide of mercury, but on this question the 



INFLUENCE OF SUNLIGHT ON PAINTS AND VARNISHES 265 

writer has doubts. Some of the oxids oi iron, par- 
ticularly the bright red ferric oxids, are affected by light, 
and a compound results which from bright red turns to 
brown, probably a change tending towards the formation 
of ferrous oxid. 

We know that a large number of the organic dyestuffs 
tend to bleach in the sunlight, but sunlight alone is 
never very active regarding the decomposition of colors 
when air is excluded, for even mercury vermillion is 
regarded as permanent when it is covered by a coat of 
varnish. This is largely true of the organic lakes and 
finer colors used for coach painting. Linseed oil itself 
is bleached by sunlight, but this is a chemical change 
produced by the actinic rays in which the green chloro- 
phyll is changed to pale yellow. 



CHAPTER XXV 

Paint Vehicles as Protective Agents Against 

Corrosion ^ 

A careful search of the literature of the past twenty 
years has failed to reveal anything like a systematic 
investigation of the relative value of different vehicles 
used ifi the manufacture of paints for structural steel 
and the prevention of corrosion. There are a. few isolated 
cases in which boiled linseed oil,^ Kauri linseed oil var- 
nish ' and spar varnish as protective coatings on structural 
steel were studied. For many years past much has been 
written and many investigations have been made on the 
protective quality of the pigments, but no one has appar- 
ently made any study of the vehicles. 

It is quite obvious that without a vehicle a pigment is 
useless, and the author knows of no instance where a pig- 
ment could be used alone, with perhaps the single exception 
of Portland cement, if that may be classed as a pigment; 
even then, Portland cement would be useless unless water 
were used as a vehicle. The example need hardly be called 
to your attention of taking a dry pigment and using water 
as a vehicle to show you that when the water evaporated 
it would leave the pigment, and the pigment in turn 
would leave the metal ; and yet, to the best of the author's 

^ Journal of Society of Chemiail Industry, June 15, 191 5. No. 
II, Vol. XXXIV, by Maximilian Toch. 

- C. \'on Krcybi^, harbcn /Ag., 17, 1766-8; J. N. Friend, 
Camc^ic Scholarship Report, Iron and Steel Inst., May, 191^, pp. i-g. 

* Address of Prof. A. H. Sahin before .\merican Society of 
C^ivil Engineers, Xov. 4, 1896, reported in Engineering Xews, July 
28, 1898. 

266 



PROTECTIVE AGENTS AGAINST CORROSION 267 

knowledge, nobody has paid any attention to the very im- 
portant role that is played by the vehicle itself. There is 
an old proverb which says, "One hand is useless, for one 
hand washes the other," and it seems that the same is 
true with reference to vehicle and pigment, for one is of 
little value without the other, and if any value is to be 
attached to either of them the vehicle has by far the 
advantage, because there are some vehicles which protect 
for a considerable length of time. 

With this end in view exposure tests were made in 
191 3, in which fifty- two steel plates (in duplicate) were 
carefully freed from grease by washing with benzol, 
dried, sanded, and rubbed clean with pumice, and then 
coated with all the paint vehicles or protective vehicles 
to the extent of fifty-two in number, many of which, of 
course, are seldom, if ever, used alone, and some of 
which are failures a short time after they are put on. 
However, the author wanted to do this thing thoroughly, 
and for this purpose selected the same quality of steel, 
known as cutlery steel, which has been used by him for 
many years for his exposure tests. It is a steel which 
rusts very rapidly. 

Those plates must be eliminated which have shown no 
rusting in the year and five months that they have been 
exposed. These were coated with the paraffin or machin- 
ery oil compounds, and it would be poor advice to any 
engineer to coat steel with paraffin compounds, for the 
method of cleaning before the application of any good 
paint would have to be very carefully followed out, 
since no protective paint would hold on steel that re- 
tained the least trace of a paraffin coat. Then the 
paraffin, or non-drying oils, all collect a great deal of 
dirt, which showed that this would have to be entirely 
removed before any paint could be applied. 



268 CHEMISTRY A\D TECHNOLOGY OF PAINTS 

Plate No. 41 showed excellent results, and a material 
of this kind would not be so very expensive where en- 
gineers demand that steel be coated with a clear liquid 
in the shop so that the steel may be inspected in the 
field. This was composed of half spar varnish and half 
stand oil. Stand oil is practically a polymerized linseed 
oiL Linseed oil when heated to 550° F., with a drier 
like Japanner's Prussian brown or borate of manganese 
will produce a ver\' thick viscous liquid, which is largely 
used as a patent leather finish. This can be reduced 
with 50 per cent of thinner and still have the fluid- 
ity or viscosity of raw linseed oil, and is, therefore, 
inexpensive. 

Plate No. 50 was coated with a material containing 
10 per cent of paraffin oil, which might be classed as 
an adulterated linseed oil, and while it showed up xexy 
well, it could not be recommended because on an exp)osed 
structure like a bridge a coat of good protective paint 
would not adhere very thoroughly. 

Plate No. 52 has taught a valuable lesson with regard 
{o the use of raw China wood oil which is heated to a suf- 
ficient ilogree of heat to take 10 per cent of a tungate 
drier, and then thinned with 15 per cent of benzine. This 
made a material which is hardly more expensive than 
gcHxL boiled linseed oil, and left a most excellent surface 
for repainting. In fad, this has proved itself the equal 
o\ plates No. 22 and No. 23, with the addition of a better 
surface for repainting. 

Plate No. 40 was coated with kettle-boiled linseed oil, 
and is very good, but this material might be regarded 
h\ some engineers as too expensive for application, as 
it took all dav to make this oil. A carefullv selected 
linsecil oil was chosen to start with, to which was added 
5 l)er cent of litharge and no other drier. This oil dried 



PROTECTIVE AGENTS AGAINST CORROSION 269 

very badly, but when it did dry produced a good flexible 
film which lasted. This must not be confounded with 
the average boiled linseed oil of commerce. 

The various coatings used in these exposure tests 
have been divided according to their protective value 
into five classes : 

1 and lb — Those vehicles "which have little or no 
value for the prevention of rusting. 

(a) The raw and refined drying and semi-drj^ing 
vegetable oils. (Plates Nos. i, 7, 8, 13, 35, 36, 47, 48.) 

(b) The same oils to which 10 per cent of drier 
had been added. (Plates Nos. 2, 3, 4, 6, 9, 10, 11, 12, 

14, 34.) 

(c) The more or less volatile paint thinners. (Plates 

Nos. 17, 18, 19, 20, 33.) 

(d) Solutions of celluloid and pyroxylin. (Plates Nos. 

24, 25.) 

(e) The liquid (at room temp.) paraffin oils. (Plates 
Nos. 21, 30.) 

2 — Those vehicles which showed some degree of 
protection, though not very much at best. 

(a) Wood-oil varnishes containing a certain percentage 
of rosin. (Plates Nos. 26, 29.) 

(b) Copal-wood-oil varnishes. (Plates Nos. 27, 28.) 

(c) Varnishes made from linseed oil which had been 
thickened and oxidized by blowing with air, oxygen or 
ozonized air. (Plates Nos. 32, 37.) 

This compared with the results obtained below with 
cooked-oil varnishes proves conclusively that the film 
yielded by a blown oil is not nearly as waterproof and 
resistant to severe weather conditions as that formed by 
a boiled or polymerized oil. 

3 — Varnishes or varnish mixtures which protected 
the steel very nicely as long as weather conditions were 



PROTECTIVE AGENTS AGAINST CORROSION 271 

seed oil which contains paraffin oil in some quantities when 
apparently dry shows minute globules of paraffin oil in 
w^et condition when the film is heated over ioo° C. A 
film of linseed oil containing lo per cent of paraffin oil 
after it is six months old can be extracted with naphtha 
and shows uncombined paraffin oil. These experiments 
prove conclusively that it is dangerous to mix a paraffin 
oil with linseed oil for any purpose, excepting where 
it is not necessary, or not the intention, to repaint 
subsequently. 

Note: All the photographs submitted (see pages 274- 
27s) were taken during December, 1914. 



CHEMISTRY AXD TECHKOLOCY OF PAIXTS 



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CHAPTER XXVI 

The Electrolytic Corrosion of Structural Steel* 

Engineers have commented publicly on the electro- 
lytic corrosion of structural steel, particularly those parts 
known as grillage beams, supporting columns and base 
posts, which are either in the ground or surrounded by 
concrete and partly above the ground, with a view of 
determining beyond question at which of the poles corro- 
sion occurs, and whether one pole is more active than the 
other. 

The author performed an experiment by taking two 
sheets of high grade watch spring steel, which is ex- 
tremely susceptible to corrosion, and connecting them 
with the ordinary bluestone telegraphic cell. A volt am- 
meter was placed in the circuit and the two pieces of steel 
buried up to 5 in. in sand. Careful observation was made 
every day to see that the current was uniform, and the 
sand was first moistened with salt water and then contin- 
ually moistened with distilled water so that the same 
strength of salt solution was maintained. This experi- 
ment was conducted for 100 days, and assuming that the 
current travels from plus to minus, or from anode to 
cathode, the anode being connected with the copper and 
the cathode being connected with the zinc, corrosion was 
noticed almost immediately at the anode, and the plates 
showed violent corrosion at the anode and practically no 
corrosion at the cathode. These plates indicated some 

' By Maximilian Toch. Reprinted from Proceedings of 
American Society for Testing Materials, Volume VI, 1906. 

276 



ELECTROLYTIC CORROSION OF STRUCTURAL STEEL 277 

slight corrosion on the cathode, which, however, was 
principally chemical corrosion. 

The strength of the current was .05 of a volt and the 
distance between the plates, varjdng in the damp sand, 
was i^ inches, and the amperage varied from .02 to .05. 

The current was measured by a "Pignolet," direct 
reading, continuous current volt-ammeter, and the amount 
of current which produced this corrosion was exceptionally 
small. 

Another experiment was tried exactly in the same 
manner, for a shorter period of time, but instead of using 
two plates, three plates were used, the third one being 
designated as the "free" plate, in which chemical corro- 
sion had full sway. At the end of six days these plates 
were removed; the anode showed marked corrosion, the 
cathode plate showing practically no corrosion at all, and 
the "free" plate showed a fair average between the 
cathode and the anode, and it can be deduced that the 
difference between the cathode and the anode corrosion 
is equal to the "free" corrosion. In other w^ords, there 
is many times more corrosion on the anode than there is 
on the "free" plate, and no corrosion on the cathode 
plate. 

The rust first produced was the green ferrous oxid, 
Fe(0H)2, which, being a very unstable product, was 
quickly converted in the air into FegOa, N(H20). 

The current was .1 of a volt and .1 of an ampere 
which produced this result. The salt solution was four 
times as strong as that produced in the first experiment. 

A third experiment was, however, of the greatest im- 
portance, owing to the fact that the author attempted 
to imitate the conditions exactly as they existed in 
buildings. The same kind of steel was taken and bedded 
in various mixtures of concrete, starting from neat 



278 CHEMISTRY AND TECHNOLOGY OF PAINTS 

cement and going up to 1:3:5. There is a -well-known 
law in physical chemistry that reactions which take place 
with an increase of pressure are retarded by an increase 
of pressure, and the question has come up as to whether 
it is possible for steel to corrode when surrounded by 
concrete, many engineers holding that the alkaline na- 
ture of the cement will prevent the corrosion, and others 
holding that in conjunction with this condition the pres- 
sure exerted by the concrete prevents chemical decom- 
position. The author is glad to be able to throw some 
Ught on this subject, and the following experiment was 
carried out: 

In the first place cement was taken of known com- 
position, agreeing practically with the definition as quoted 
in the Journal of the American Chemical Society, July, 
1903, when the question of the permanent protection of 
iron and steel by means of cement was thoroughly 
gone into. The cement for these experiments was 
what might be termed the tri-calcic silicate and 
calcium aluminate. This is in contradistinction to the 
general classes of Portland cements containing dicalcium 
ferrite as a part of their composition and free calcium 
sulphate in excess. A cement of the calcium aluminate 
class, free from iron and free from calcium sulphate, is a 
well-known protector of steel and iron against corrosion, 
and this class of cement was used in these experiments. 
The pieces of steel were connected up with six elementar}'' 
cells of sufiiciently high voltage and amperage, and it was 
impossible to get a direct reading from the volt-ammeter, 
the instrument being too sensitive. The seven parts of 
cement containing the steel strips were then put into the 
circuit and wet every few hours with solutions of 5 per 
cent sodium chloride and i per cent nitric acid, and water, 
in order to increase their conductivity and produce corro- 



ELECTROLYTIC CORROSION OF STRUCTURAL STEEL 279 

sion as rapidly as possible. The average strength of the 
current was .05 volts and .05 amperes throughout the entire 
experiment. Corrosion was immediately noticed at the 
anode pole, and the pat of neat cement, which should have 
protected the steel most perfectly against all kinds of corro- 
sion, showed a hair line split colored with rust at the end 
of the third day, which demonstrated that the chemical 
reaction of rusting had taken place at the anode ; that the 
molecular increase had likewise taken place, and the pres- 
sure caused by the molecular increase had split the block. 
The steel in each alternate pat was painted half the length 
which was embedded in the cement with an insulating 
paint of known composition having a voltage resistance of 
625 volts per millimeter. The results obtained after these 
various briquettes were broken open demonstrated that 
electrolytic corrosion takes place most violently at the 
anode unless the steel be coated with an insulating 
medium. 

Cement, concrete, or even neat cement, is therefore no 
protection against electrolytic corrosion, unless the steel be 
insulated as heretofore mentioned, and there was absolutely 
no corrosion where coated with insulating material. It 
must be noted that the cathode in all these experiments 
was perfectly free from any signs of oxidation. 

The result of this entire series of experiments is to 
prove conclusively that electrolytic corrosion of struc- 
tural steel embedded in concrete or sand takes place only 
at the anode and there with great violence; and further- 
more, that the cathode is protected by the electrical cur- 
rent. The popular impression that cement is a protector 
against all kinds of corrosion is fallacious. The anode 
does not only rust very violently, but a molecular in- 
crease of volume may take place which will split the con- 
crete shell. 



28o CHEMISTRY AND TECHNOLOGY OF PAINTS 

Another conclusion arrived at is that the electrolytic 
rusting of grillage beams of buildings need not be feared 
if the structural steel be protected by a good insulating 
material, but the insulating medium should form a bond 
with concrete. 



CHAPTER XXVII 

Painters' Hygiene 

All paints should be regarded as poisonous, and even 
though it may be understood as a general rule that 
materials like ultramarine blue are non-toxic or that 
silica has no effect upon the system, it is unwise for the 
paint manufacturer to permit his men either to breathe 
these in dry dust form or to allow his workmen to eat 
their meals before washing themselves thoroughly. We 
are all very familiar with the fact that white lead pro- 
duces lead poisoning, but in any well-regulated factory 
there is no excuse for this, and the amount of lead 
poisoning produced in factories like the large lead manu- 
factories in the United States is reduced to a minimum 
because the workmen are looked after most thoroughly. 
Workmen who are employed in a dusty atmosphere should 
always wear respirators, and workmen who work with 
lead products should not be permitted to grow mous- 
taches, as the dust of many of the poisonous pigments 
settles in the moustache and is then absorbed through 
the nose. White lead under the finger nails is absorbed 
into the system, and a careful watch of these things will 
prevent any disease among the men; but all in all there 
is more sensationalism and hysteria on this subject than 
is warranted by the results, for in paint factories where 
sufficient care is taken there is practically no illness 

among the men. 

281 



282 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Paint vapors are all toxic, and any painter who is 
ignorant enough to apply any paint material in a closed 
room does not deserve to be a painter. Even materials 
like pure spirits of turpentine, which are known to have 
medicinal qualities, when bre.athed in large quantities are 
supposed to produce headache and vertigo, and the fumes 
of benzol, benzine and alcohol give the same results; 
therefore all people who apply paint should do so in well- 
ventilated rooms. Large vats which are varnished on the 
interior like brewers' vats, or water tanks which are 
painted on the inside, are generally ventilated by the 
engineers in charge by having fresh air pumped in con- 
tinually to the men from the top and by simply pumping 
out the vapors from below, as practically all of the 
materials used in the manufacture of paint give oflF vapors 
which are heavier than air. 

Paint vapors are also inflammable, and any fire 
resulting from careless smoking or throwing lighted 
matches near paint is likely to produce disastrous results, 
but much information has been disseminated on this 
subject, particularly through the railroads, who now 
demand caution labels printed on each package before 
it is shipped with the result that many lawsuits which 
were instituted formerly against the manufacturer are 
not permitted today. The same is true with regard 
to the vapors arising from paint. It has been a practice 
among certain questionable lawyers to institute suits 
against paint manufacturers for illness, headaches, nausea, 
vertigo and such other physical ills as have resulted from 
the fumes of paint, and few of these lawsuits have ever 
been tried, because the paint manufacturer in former 
times has been inclined to settle a suit of this kind 
rather than go to court, but these cases are not as 
frequent as they formerly were on account of the wide- 



PAINTERS' HYGIENE 283 

spread knowledge of the subject. Fumes arising from 
paint are not dangerous in the open air, but if a painter 
is careless in a closed room it is certainly his fault, and a 
man who knows so little about paint should not be per- 
mitted to use it. 



CHAPTER XXVIII 
The Growth of Fungi on Paint 

Fungi must not be confounded with bacteria. Bac- 
teria are invisible micro-organisms, and whether they 
thrive on paints has never yet been established. Their 
existence in oil or paint media has never been proved. 
Experiments made by the 
author in which various 
bacteria were grown in 
gelatin or agar agar have 
^ demonstrated that when 
I turpentine, benzine, linseed 
I oil, vamish or jmints of 
any character, excepting 
^'' those containing water, were 
added, they rapidly per- 
ished. Fungi, howe\'er, are 
K(]. 71. ()i.i\h: c.KKFv iiNcrs, srowing totally different organisms. 
"," !'■''"* — '''"■"""'^'^'K'^i* ^"°°- A fungus is derived from a 
spore which floats in the 
air and which jiracticall}- is a microscopic seed. When 
this falls on fertile ground it sprouts and becomes a white 
downy mass, which is known as the hypha. This 
downv mass later on assumes a color, which may be 
cither grav, green, yellow or black, and is known under' 
the i)opular title of mildew, which is in reality a fungus 
or micro-organic growth of the vegetable t\-pe. 

What mav be poistjnous to a human being is evi- 
dently non-poisonous or neutral to a fungus, for fungi 




THE GROWTH OF FrNGI O.V PAI.\T 285 

can grow and do grow on practically all of the barium 
precipitates, which are known to be highly poisonous. 

A fungus needs both warmth and moisture for its 
propagation, and so we will frequently find that on the 
south side of a house at the seashore, where moisture will 
collect and the temperature will be fairly uniform, fungi 
will sprout on a painted surface and frequently destroy 
the paint. This is more noticeable in the tropics than it 





No. 71. Pemc'ilil'u Chustaceiim — No. 71, Asi'ikmii-i^^ Nk.ik 

Pholomirrogniph x'kjo. a comniiiii — I'h.iioniu Ti.i;r,i]>h > 100, 

green or cellar fungus (vhich groivs on old funitus fouiul un piiint. 
many forms of puinl. 

is in the North, and more noticeable in the European 
countries than it is in America, for the humidity in the 
United States is way below normal for more than half 
of the j^ear whereas the humidity is fairly constant in 
Europe and in the tropics. Some of these fungi are very 
disagreeable, particularly the black types, which will 
grow on the interior of houses, and which always, propa- 
gate better in a cellar than they do in a garret, for light 
has a tendency to kill them. 

The fungi that are found on paint may be classified 
into the following varieties: 



_J 



• .•1 



286 CHEitlSTRY AXD TECHNOLOGY OF PAIXTS 

1. Peniciiium Crustaceum tj^s, of which there are 
many varieties, but all of which are greenish or olive 
grayish. 

2. Aspergillus Niger, 
which is distinctly black 
and ver>' tenacious. ' 

3. Rhizopus Nigricansy 
which is brown and black, 
and which appears gener- 
ally in the Fall of the year. 

4. Aspergillus Flavus, A^ 
which is yellow and orange, ^9 

and which grows freely on n^. „ AsPEKonxos Niger -Pbot^ 

a putrid Stwl or near de- micrograph xioo, blact (ungus fre- 
quently (ound on paint in cellars. 

understood that the use of 
to be recommended, for in 
breweries, malt houses, 
rooms which have swim- 
ming pools, and cellars 
which have been used for 
storage, these fungi grow 
at times, and it seems as 
if there is nothing which 
kills them. The best way 
to get rid of them is to 
wash the surface copiouslv 
with soap and water and 
then sjiray a mixture of car- 
bolic acid and formaldehyde 
and afterward bichloride of 
mercury, but a man apply- 
ing a material of this kind must use a mask and a 
resi)irator. 



caying vegetable matter. 

It must be generally 
fungicides is net always 




THE GROWTH OF FUNGI ON PAINT 287 

Many a complaint has reached a paint manufacturer 
that his paint has turned black in spots under the eaves 
of a roof or in a ground- 
floor room, and the manu- 
facturer on account of 
ignorance has supplied 
fresh paint free of charge, 
or the painter has done 
the work over again, when 
as a matter of fact the 
fault was due entirely to 
fungus growth. It is well, 
therefore, for the paint 
chemist to familiarize him- 
self with at least these 
few fungi, as they are the 
principal types which flourish on paint. 




No. 76. CLADOSPOHIUU HERBAkUM — 

Photomicrograph x6oo, a pale fungus 
growing on damp walls. 



ANALYSIS OF PAINT MATERIALS 
Analysis of White Lead 

Gravimetric Methods — Estimation as PbS04 

Lead. — Dissolve i g. in dilute acetic acid, filter, wash 
and weigh the insoluble residue. To the filtrate add lo 
c.c. of dilute sulphuric acid (i:i) and evaporate on the 
steam bath. Allow to cool, dilute cautiously to loo c.c, 
add ID c.c. of alcohol and stir well. Filter on a Gooch or 
alundum crucible, wash with water containing i p)er cent 
of sulphuric acid and lo per cent of alcohol, and finally 
with alcohol alone. Dry at iio° C. 

Lead sulphate is appreciably soluble in concentrated 
sulphuric acid and slightly soluble in water. It is practi- 
cally insoluble, however, in i per cent sulphuric acid and 
in alcohol. It is ver\' soluble in hot, concentrated am- 
monium acetate solution. 

Estimation as PbCr04 

Treat i g. in a beaker with hot water and just suf- 
ficient acetic acid to dissolve the white lead, using no 
more than 5 c.c. of acetic acid in excess. Filter off from 
the insoluble residue. Dilute to 100 c.c, heat to boiling 
and add an excess of a neutral, saturated solution of 
potassium dichromate solution. Allow to cool. Filter 
on a Gooch or alundum crucible, wash and dr>' at 130° C. 

Volumetric Methods — Estimation as Molvbdate 

Dissolve 0.5 g. of white lead in 5 c.c. of concentrated 
hydrochloric acid by boiling. Add 25 c.c of cold water 

2SS 



ANALYSIS OF PAINT MATERIALS 289 

and proceed as indicated below, under "Standardization 
of Ammonium Molybdate." 

Lead is precipitated as PbMo04 by a standard solu- 
tion of ammonium molybdate from hot solutions slightly 
acid with acetic acid. The solutions required are: 

(a) Ammonium molybdate — Dissolve 4.25 g. in i litre of water 

(b) Tannic acid solution — Dissolve o.i g. in 20 c.c. of water 

Standardization of Ammonium Molybdate. — Weigh off 
about 0.2 g. pure lead foil in a small Erlenmeyer flask 
and dissolve in 6 c.c. of nitric acid (1:2). Evaporate 
the solution just to dryness. Treat the residue with 
30 c.c. of water and 5 c.c. of concentrated sulphuric acid 
and shake well. The precipitated lead sulphate is allowed 
to settle, filtered and washed with dilute sulphuric acid 
(1:10). Filter and precipitate are placed in an Erlen- 
meyer flask and boiled with 10 c.c. of concentrated 
hydrochloric acid until completely disintegrated. Then 
add 15 c.c. more of concentrated hydrochloric acid, 25 c.c. 
of cold water and neutralize with ammonia until slightly 
alkaline to litmus paper. Reacidify with acetic acid. 
Dilute to 200 c.c. with hot water and heat to boiling. 
Titrate, using the tannic acid solution as outside indicator, 
until a brown or yellow coloration is obtained with the 
latter. 

Precautions. — Titration must be carried out hot, at 
about 90° C. If the solution should cool down in the 
course of titration, reheat it. Here, as in the case of the 
titration of zinc with potassium ferrocyanide, the scheme 
of dividing the solution into two unequal parts may be 
used. 

To determine the excess of ammonium molybdate 
necessary to affect the indicator, place in an Erlenmeyer 
flask 25 c.c. of hydrochloric acid, neutralize until slightly 
alkaline to litmus, then reacidify with acetic acid. Dilute 



290 CHEMISTRY AND TECHNOLOGY OF PAINTS 

to 200 c.c, heat to boiling, and add ammonium molybdate 
drop by drop until the outside indicator is affected. 

Antimony and bismuth do not affect the results 
obtained by this method. Barium and strontium give 
ver>^ low results, while calcium yields but slightly low 
results. The alkaline earth sulphates tend to retard the 
solution of the lead. This difficulty can be overcome by 
thoroughly washing the lead sulphate and then boiling it 
with sufficient ammonium acetate. 

Carbon Dioxid and Combined Water. — i g. of white 
lead is weighed off in a porcelain boat. -The latter is 
then placed in a combustion tube and heated in a current 
of dry air free from carbon dioxid. The water is col- 
lected in calcium chloride tubes, and the carbon dioxid 
in potash bulbs or soda lime tubes. 

Carbon dioxid may be determined by evolution by 
treating white lead with dilute nitric acid. Use a reflux 
condenser in connection with the evolution flask and dr>' 
the carbon dioxid by passing through calcium chloride 
before absorbing in the potash bulbs or soda lime tubes. 

Basic Lead Sulphate 

Lead and Zinc {gravimetric), — Digest i g. for ten min- 
utes in the cold with 20 c.c. of 10 per cent sulphuric acid. 
Filter, keeping most of the residue in the beaker, and 
wash twice by decantation with i per cent sulphuric acid. 
The filtrate from the sulphuric acid teatment is re- 
served for the determination of zinc which is carried out 
by any of the methods outlined under ^*Zinc Oxid/* 
Preferably precipitate as phosphate. Calculate the zinc 
to ZnO. 

Dissolve the residue in the beaker with hot concen- 
trated slightly acid ammonium acetate solution pouring the 
solution through the filter. Wash the latter with ammo- 



• ANALYSIS OF PAINT MATERIALS 291 

nium acetate and then with hot water. Dilute to 200 c.c, 
add an excess of a neutral saturated solution of potassium 
dichromate and bring to boiling. Allow to cool, and filter 
on a Gooch or alundum crucible. Dry at 130° and weigh 
as PbCrO;. 

Lead (volumetric). — Treat 0.5 g. sample with 30 c.c. of 
water and 5 c.c. of concentrated sulphuric acid, and 
proceed as outlined under "Estimation as Molybdate." 

Sulphates.^ — Dissolve 0.5 g. by boiling in a mixture of 
25 c.c. water, 10 c.c. aqua ammonia and enough con- 
centrated hydrochloric acid to give a slight excess. Dilute 
to 200 c.c. and add a piece of pure thick aluminium foil 
large enough to nearly cover the bottom of the beaker. 
This should be kept at the bottom by means of a glass 
rod. Boil gently until the lead is precipitated. When 
the lead no longer adheres to the aluminium, the precipi- 
tation may be considered complete. Filter and wash 
wath hot water. A little sulphur-free bromine water is 
added to the filtrate, the latter is boiled, and sulphates 
determined by precipitation with barium chloride in 
the ordinary way. 

If desired the sulphates may be determined as indicated 
under Analysis of "Zinc Lead." 

Sulphur Dioxid. — Digest about 2 g. in the cold with 
5 per cent sulphuric acid, and titrate with — iodine solu- 
tion, using starch as indicator. 

Analysis of Zinc Lead 

Lead. — i g. of the material is heated on the steam 
bath with 20 c.c. of hydrochloric acid (1:1) and 5 g. 
of ammonium chloride. The solution is diluted to 250 
c.c. with hot water and boiled. This treatment should 
suffice to dissolve a pure zinc lead. 

^ Holley, "Analysis of Paint and Varnish Products," 191 2, p. 104. 



292 CHEMISTRY AND TECHNOLOGY OF PAINTS 

The insoluble residue, if any, is filtered, weighed, and 
examined for impurities. Neutralize the filtrate with 
ammonia, reacidify slightly with hydrochloric acid, and 
precipitate the lead with hydrogen sulphide. 

Allow the precipitate to settle, filter oJ0F the liquid, 
and wash the precipitate several times by decantation 
with hydrogen sulphide water. The precipitate is finally 
dissolved in hot, dilute nitric acid, treated with an excess 
of sulphuric acid, and evaporated to SO3 fumes. 

Allow to cool, dilute cautiously with 100 c.c. of cold 
water, filter off the precipitated lead sulphate on a Gooch 
crucible, wash several times with dilute sulphuric acid, 
and finally once with alcohol. Dry at 130° C, and 
weigh as PbS04. 

Zinc. — The filtrate from the lead sulphide precipitate 
is boiled to expel hydrogen sulphide, treated while hot 
with a few drops of HNO3, then rendered slightly am- 
moniacal, and any precipitate which is formed is filtered 
off. The filtrate is then slightly acidified with acetic 
acid, heated to boiling and a stream of sulphuretted 
hydrogen passed in to precipitate the zinc. The latter 
is filtered and washed with water containing a small 
amount of acetic acid saturated with hydrogen sulphide, 
using a Gooch or alundum crucible for filtering. 

In filtering zinc sulphide, keep the crucible full of 
liquid or wash water until the precipitate is completely 
washed. Only then may the precipitate be allowed to 
drain free from wash water. 

The zinc sulphide is then dissolved in dilute hydro- 
chloric acid, the sulphuretted hydrogen expelled by boiling, 
and the zinc determined either volumetricallv bv the 
ferro-cyanide method or gravimetrically by precipitation 
with a slight excess of sodium carbonate, and ignition to 
ox id. 



ANALYSIS OF PAINT MATERIALS 293 

Calcium and Magnesium. — The filtrate from the zinc 
sulphide is evaporated to a small bulk and the calcium 
determined by precipitating hot from a slightly ammoni- 
acal solution with ammonium oxalate. Magnesium is 
determined as usual. 

Soluble S(Uts. — To determine the presence of zinc sul- 
phate, I g. is digested with loo c.c. of water, filtered, 
and the sulphate determined in the filtrate as usual, with 
barium chloride. 

Total Sulphates. — Dissolve 2^ g. of sodium car- 
bonate in a beaker with 25 c.c. of water, add 0.5 g. 
of the sample, boil gently for about ten minutes and 
allow to stand for several hours. Dilute with hot water, 
filter and wash until the filtrate is about 200 c.c. 

Render the filtrate slightly acid with hydrochloric, 
boil to expel carbon dioxid and precipitate the sulphate 
with a slight excess of barium chloride solution. 

Filter, wash and weigh as BaS04. Calculate the lat- 
ter to PbS04. 

Zinc Oxid 

Insoluble. — Dissolve i g. in hot dilute acetic acid. 
Filter, wash and weigh any insoluble residue. If the 
latter is very small in quantity, it should be deter- 
mined by dissolving a proportionately larger quantity of 
zinc oxid. 

Zinc. — Neutralize the filtrate with ammonia, then 
make faintly acid with acetic acid, dilute to 300 c.c, and 
precipitate with sulphuretted hydrogen. The solution 
should be kept hot during the precipitation, and should 
smell strongly of hydrogen sulphide at the end. Allow 
the precipitate to settle, decant through an alundum or 
Gooch crucible, keeping the crucible full of liquid during 
the filtration, wash the precipitate in the beaker with a 



294 CHEMISTRY AND TECHNOLOGY OF PAINTS 

hot 2 per cent acetic acid solution saturated with hydro- 
gen sulphide, finally transferring the zinc sulphide to the 
crucible and allowing the last wash water to drain com- 
pletely. The zinc sulphide is dissolved in dilute hydro- 
chloric acid and boiled to expel H2S (test with lead acetate 
paper held in the escaping vapors from the beaker or 
flask to show the presence of hydrogen sulphide). 

Gravimetric Methods for Zinc, — (a) Precipitation as Phosphate 

The solution is rendered very faintly acid by almost 
completely neutralizing wdth ammonia, diluted to 150 c.c. 
and heated on the steam bath. Add to the solution on 
the steam bath about ten times as much di-ammo- 
nium phosphate ^ as zinc present. Heat for 15 minutes 
longer. The crystalline zinc ammonium phosphate is 
filtered through a Gooch or alundum crucible, washed 
with hot I per cent ammonium phosphate solution until 
free from chlorides, then with cold water and finally with 
50 per cent alcohol. Dry at 120° C. for one hour and 
weigh as ZnNH4P04. 

(h) Precipitation as Carbonate 

The zinc chloride solution is carefully neutralized in 
the cold with sodium carbonate solution until a precipi- 
tate begins to form. The solution is then heated to 
boiling, and precipitation completed by adding a slight 
excess of sodium carbonate (use phenolphthalein as indi- 
cator). Ammonium salts must not be present. Filter on 
a Gooch crucible, wash, ignite and weigh as ZnO. 

Volumetric Method. - -YAnc is precipitated from hot 
somewhat acid solutions by the addition of potassium 
ferro-cyanide according to the following reaction: 

^ Dissolve in cold water and add dilute ammonia until faint I v 
pink with phenolphthalein. 



ANALYSIS OF PAINT MATERIALS 295 

3ZnCl2 + 2K4FeC6N6 = ZnsKzFeoCCN)^ + 6KC1 • 

The end point is indicated by a solution of uranium ni- 
trate as outside indicator. A brown coloration is produced 
when a drop of the solution containing the excess of 
potassium f errocyanide is added to a drop of uranium 
nitrate solution on a spotting tile. 

Solutions Potassium F errocyanide, — Dissolve 21.6 g. 
of crystallized salt, K4FeC6N6-3H20 in cold water and 
dilute to one liter. One c.c. of this solution is equivalent 
to about 0.005 g. zinc. 

Uranium nitrate 5% solution 

Ammonium chloride 10 g. per liter 

Standardization of Ferrocyanide. — Weigh out two or 
three portions of 0.2 to 0.25 g. of pure ignited zinc oxid. 
Dissolve in 10 c.c. of hydrochloric acid (1:2), add sodium 
carbonate solution or ammonia until a slight permanent 
precipitate is formed, redissolve the latter with one 
or two drops of hydrochloric acid, add 6 c.c. of concen- 
trated hydrochloric acid and 10 g. of ammonium chloride. 
Dilute to 180 c.c, heat to 70° C. and titrate with ferro- 
cyanide solution until the end point is reached. To 
determine the end point rapidly divide the zinc solution 
into two unequal parts. Titrate the smaller part run- 
ning in the ferrocyanide solution i c.c. at a time. When 
an excess has been added pour in the rest of the zinc so- 
lution, run in i c.c. less than the quantity of potassium 
ferrocyanide previously added, and finish the titration 
drop by drop. 

A blank must be deducted because of the excess of 
potassium ferrocyanide required to develop the brown 
coloration with uranium solution. 

To determine the allowance, add 6 c.c. of concentrated 
hydrochloric acid and 10 g. of ammonium chloride to 200 



296 CHEMISTRY AND TECHNOLOGY OF PAINTS 

c.c. of water in a beaker, heat to 70^ C, and add the 
ferrocyanide solution until the brown coloration is obr 
tained with the outside indicator. The correction should 
be less than 0.5 c.c. Deduct this amount from all future 
titrations. 

Determination of Zinc. — To determine zinc in the 
solution obtained by dissolving ZnS in hydrochloric add 
and expelling hydrogen sulphide, neutralize with ammonia 
or sodium carbonate, reacidify slightly with dilute hydro- 
chloric acid, and proceed as outlined under '^ Standardiza- 
tion of Ferrocyanide." The presence of a small amount 
of lead does not interfere with the accuracy of the above 
method. 

Soluble Impurities. — Most zinc oxids are contami* 
nated with small quantities of cadmium and traces of iron, 
copper and lead. The cadmium ^ is best determined by 
dissolving a relatively large amount, 25 to 50 g., of adnc 
oxid in dilute sulphuric acid, filtering, diluting to 400 c.c. 
and precipitating as sulphide in the presence of an 
excess of about 5 c.c. of concentrated sulphuric acid in 100 
c.c. of solution. Filter, wash, redissolve in sulphuric acid 
and reprecipitate as sulphide. Dissolve into a crucible 
with as small an amount of sulphuric acid as possible. 
Evaporate cautiously and ignite to CdS04. 

LiTHOPONE 

Method I 

Zinc Oxid. — Digest i g. with 100 c.c. of i per cent 
acetic acid at room temperature for one half hour. 
Filter, wash and weigh the insoluble. The loss in 
weight represents the zinc oxid present. 

* For electrolytic meth(xi of determining Cadmium, see E. F. 
Smith's " P^lectro-Analvsis/' 



ANALYSIS OF PAINT MATERIALS 297 

Insoluble and Total Zinc. — Treat i g. in a 200 c.c. 
beaker with 10 c.c. of concentrated hydrochloric acid, 
mix, and add in small portions i g. of potassium chlorate 
(this should be carried out under a hood); evaporate on 
the steam bath to ^ the volume. Dilute with hot water, 
add s c.c. of dilute sulphuric acid (1:10), boil, filter, and 
weigh the insoluble. The latter is barium sulphate. The 
zinc is determined in the filtrate by the methods outlined 
under "Zinc Oxid." 

Method II 

Soluble Salts. — Treat 2 g. of lithopone with 100 
c.c. of hot water. Digest for a few minutes and filter 
on a Gooch crucible (test the filtrate for Ba, Zn and SO4). 
Wash with hot water and finally once with alcohol. 
Dry the crucible in the air oven at 100° C. and deter- 
mine loss in weight. The latter is equal to the per- 
centage of moisture present plus the water soluble 
salts. 

Zinc Oxid. — Digest for § hour, without warming, a i 
g. sample with 100 c.c. of i per cent acetic acid. Filter, 
wash, and determine the zinc in the filtrate gravimetrically 
or volumetrically, as outlined under "Zinc Oxid.'' Cal- 
culate to ZnO. 

Zinc Sulphide. — Transfer the filter paper and residue 
to a beaker, treat with dilute hydrochloric acid (1:4) and 
boil to drive off H2S. Filter, wash with hot water, and 
determine the zinc in the filtrate by the usual methods. 
Report as ZnS. 

Barium Sulphate. — The residue is dried, ignited, 
treated with a few drops of concentrated sulphuric acid 
in the crucible, again ignited and weighed as BaS04. 
Test the latter for clay or silica. Should any be present, 
treat the residue with hydrofluoric and sulphuric acids 



298 CHEMISTRY AND TECHNOLOGY OF PAINTS 

in a platinum crucible and evaporate to dryness. The 
loss in weight represents silica. 



Red Lead and Orange Mineral 

Lead Peroxid {Metliod I). — Dissolve 0.5 g. in a beaker 
with 30 c.c. of 2N nitric acid, heat to boiling to complete 
solution. Add 25 c.c. N/5 oxalic acid, accurately meas- 
ured from a pipette or burette, boil and titrate hot 
with KMn04. 

A blank containing the same quantities of nitric acid 
and oxalic acid is also titrated against the permanganate. 
The difference between the two titrations represents the 
amount of Pb02 reduced by oxalic acid. 

Pb304 + 4HNO3 = 2Pb (N03)2 + H2O+ HaPbO, 
PbOa + H2C2O4 = PbO H- H2O+ 2CO2 

Lead Peroxid {Metliod II). — Mix together in a small 
beaker 1.2 g. of potassium iodide, 15 g. sodium acetate 
and s c.c. of 50 per cent acetic acid. Weigh off 0.5 g. of 
red lead in a 150 c.c. Erlenmeyer flask and add the above 
mixture to it. Stir until the lead is completely dis- 
solved. Dilute to 25 c.c, and titrate with N/io sodium 
thiosulphate, using starch as indicator. 

A little red lead, especially when it is not ver>'' fine in 
texture, at first resists solution in the potassium iodide 
mixture, but dissolves, on mixing, toward the end of the 
titration. Proceed with the titration as soon as the lead is 
in solution, so as to avoid loss of iodine by volatilization. 

The reaction involved in the above method is 

PbOo -f 4HI = Vhh + 2H2O 4- 12 

The lead peroxid is reduced in the presence of an 
excess of sodium acetate when treated with potassium 
iodide in acetic acid solution. 



ANALYSIS OF PAINT MATERIALS 299 



Analysis of Iron Oxids 

Moisture. — Heat 2 g. in the air oven at 105° C. for 
two hours. 

Loss on Ignition. — Ignite i g. in a porcelain crucible 
to a red heat. The loss in weight consists of hygros- 
copic moisture, water of combination, sometimes organic 
matter, and carbon dioxid due to the presence of car- 
bonates. 

Insoluble. — Digest i g. of the oxid with 20 c.c. of 
hydrochloric acid (1:1) on the hot plate for 15 minutes. 
Filter, wash and weigh the insoluble residue. The 
latter may be examined to determine the presence of 
barytes, clay or silica. 

Iron Oxid. — Weigh off from 0.3 to i.o g., depend- 
ing upon the amount of iron oxid present, treat with 
20 c.c. of hydrochloric acid (1:1) on the hot plate until 
the residue is white, and while hot reduce with a strongly 
acid stannous chloride solution until the iron solution 
is colorless, using only one or two drops in excess. Wash 
down the sides of the beaker and the cover glass with a 
little water, add all at once 10 c.c. of a saturated solution 
of mercury bichloride, stir, and wash the whole into a 
large beaker containing 400 c.c. of cold distilled water to 
which has been added 10 c.c. of preventive solution. 
Titrate with N/io potassium permanganate to a faint 
pink. 

In the case of magnetic oxids and certain purple 
oxids, solution is facilitated by the addition of i to 3 c.c. 
of a 25 per cent stannous chloride solution. Should the 
residue after digestion on the hot plate still show greenish 
or black, filter, wash, and determine the iron in the soluble 
portion as outlined below. 



300 CHEMISTRY AND TECHNOLOGY OF PAINTS 

To determine iron in the insoluble portion, fuse in a 
porcelain crucible with five times its weight of potassium 
bisulphate for about } hour. Cool, dissolve in water and 
filter. Determine iron in the filtrate after reduction as 
outlined below. 

Stannous Chloride Solution. — Dissolve 50 g. of stan- 
nous chloride in 100 c.c. of hydrochloric acid and dilute 
to 1000 c.c. To preserve the solution, always keep a 
few pieces of metallic tin- at the bottom of the bottle. 

Preventive Solution: 

Crystallized Manganese Sulphate 67 g. 

Water 500 c.c 

Syrupy Phosphoric Acid (Sp. Gr. 1.7). . .138 c.c. 
Concentrated Sulphuric Acid 130 c.c. 

Dissolve in the order named and dilute to i liter. 

Analysis of Umbers and Siennas 

To 0.5 to i.o g., depending upon the amount of iron 
oxid present, in a casserole, add 20 c.c. of hydrochloric 
acid (1:1) and 0.35 g. potassium chloride (or 0.25 g. 
ammonium chloride), and evaporate to dryness on the 
steam bath. Heat for 10 minutes longer to expel hydro- 
chloric acid. Dissolve the soluble salts in about 25 c.c. 
of hot water, filter and wash the insoluble residue. The 
latter is dried, ignited and weighed, and reported as 
insoluble or silicious matter. (When necessary analyze 
this separately as indicated under "Analysis of Silica, 
Asbestine or Clay'\) 

To the filtrate, heated almost to boiling, there is 
added 3.0 g. of sodium acetate for every 0.3 g. of iron 
in solution, and 400 c.c. of boiling water. Heat to 
incipient boiling. By this means the iron is quantita- 
tix'cly precipitated as a basic acetate, while manganese 



ANALYSIS OF PAINT MATERIALS 301 

and other divalent metals of the group stay in solution. 
The precipitate is allowed to settle, the solution decanted 
off and filtered; the precipitate is washed several times 
with hot water, dissolved in a small amount of hot dilute 
hydrochloric acid, and either precipitated with ammonia 
or determined volumetrically as under "Analysis of Iron 
Oxids.'' The filtrate is evaporated to about half its 
volume, treat-ed with an excess of bromine water, and 
then boiled until the precipitated manganese dioxid be- 
comes floccular. The precipitate is then filtered off, 
washed, and ignited to Mn804. 

Calcium and magnesium are determined in the fil- 
trate in the usual way. When appreciable quantities of 
these two elements are present, it is best to separate the 
manganese by precipitation as sulphide. 

To determine manganese as sulphide, heat the neutral 
solution to boiling, add an excess of ammonia and am- 
monium sulphide, and continue the boiling until the man- 
ganese sulphide becomes a dirty green. Decant through 
a Gooch crucible, using gentle suction, keeping the cru- 
cible filled all the time. Wash the precipitate twice by 
decantation with 5 per cent ammonium nitrate solution con- 
taining a little anunonium sulphide, add to the crucible 
and filter, allowing the crucible to drain. The filtrate 
is acidified with dilute acetic acid boiled to expel hydro- 
gen sulphide, and the calcium and magnesium deterr 
mined as usual. The precipitated manganese sulphide 
is dissolved in a little hot dilute hydrochloric acid, 
evaporated to expel hydrogen sulphide, and precipitated 
as carbonate or phosphate. In the first case the man- 
ganese is ignited and weighed as Mn304. 

Colorimetric Determination of Manganese.^ — Dissolve 

^ Treadwell, Volume II, pages 127, 128. Marshall, Chem. News, 
83, 76 (1904). Walters, Chem. News 84/239 (1904). 



302 CHEMISTRY AND TECHNOLOGY OF PAINTS 

0.5 g. of umber or sienna in about 10 c.c. of hydrochloric 
acid (1:1) in a casserole, add an excess of nitric acid and 
evaporate to dryness to drive oflF the hydrochloric acid. 
Cool, add 20 c.c. of cold nitric acid (specific gravity 1.2) 
filter and wash with the least quantity of cold water into 
a 100 c.c. graduated flask. Make up to the mark. 
Remove 10 c.c. by means of a pipette to a graduated 
test tube, add 10 c.c. of silver nitrate ^ solution, and 2.5 
c.c. of ammonium persulphate 2 solution, mix, and place the 
tubes in water at 80 to 90° C. until bubbles of gas arise, 
and remain at the top for a few seconds. Cool the test 
tubes and compare against standard tubes made with 
known amounts of manganese. 

Mercury Vermilion 

This pigment is very expensive and therefore quite 
often adulterated. The possible adulterants are organic 
lakes, orange lead chromes, red lead, and iron oxids, as 
well as bar>les, silica or clay. 

Its high specific gravity (8.2) and its insolubility in 
alkalies, and in any one acid, distinguish it from all other 
pigments of like color. 

A pure vermilion can be volatilized completely on 
heating, leaving no residue. On account of the ex- 
tremely toxic properties of mercur>' vapors, such volatili- 
zation should be carried out in a hood having a good 
draft. 

BarytcSj Silica or Clay. — Dissolve 2 g. in aqua regia, 
or hydrochloric acid with a little potassium chlorate, and 
after evaporating to dryness take up with boiling water 
and a little hydrochloric acid. Filter and weigh the 
residue. 

^ i..:^8 g-AgnOs in 1000 c.c. of water. 
* 20^0 solution. 



ANALYSIS OF FAINT MATERIALS' 303 

Lead. — Evaporate the filtrate from the above with an 
excess of dilute sulphuric acid to SO3 fumes, and deter- 
mine lead as PbSOi. (Calcium must be absent.) 

Free mercury, free sulphur and iron may be identified 
by dissolving the mercury vermilion in potassium mono- 
sulphide (1:1), in which it dissolves readily. The solu- 
tion is colorless after the iron sulphide has settled out. 
Free mercury settles to the bottom of the dish as a gray 
sediment. 

Free sulphur is recognized by the yellow coloration of 
the solution. It may also be detected in the usual way by 
digesting with potassium hydroxid or extraction with 
carbon disulphide (if present in crystalline form). The 
quantitative determination is carried out by extracting with 
soda solution and oxidation to sulphate. 

For separating foreign adulterations such as bar>les, 
clay, litharge, chrome red, brick dust, etc., potassium sul^ 
phide may be used to advantage. After filtering, wash 
with dilute KOH solution and not with water, otherwise 
the Brunner's salt decomposes with separation of black HgS. 

The coal tar colors are identified by extraction with 
alcohol; carmines by the drop test with anmionia on filter 
paper. 

For detecting arsenic sulphide, boil with caustic soda, 
acidify with hydrochloric acid and introduce H2S gas into 
the solution. 

Analysis of Chrome Yellows and Oranges 

Organic Matter. — Test with alcohol to determine pres- 
ence of organic coloring matter. 

Insoluble. — Boil i g. for about 5 minutes with 20 c.c. 
of concentrated hydrochloric acid, adding i or 2 c.c. of 
alcohol drop by drop. Dilute with about 100 c.c. of 
boiling water. Boil a few minutes longer. Filter, wash 



304 CHEMISTRY AND TECHNOLOGY OF PAINTS 

with boiling water, and weigh the insoluble. Test the 
latter for barium sulphate, clay or silica. 

Lead. — Neutralize the filtrate with ammonia until a 
slight permanent precipitate appears. Reacidify sligfatlyy 
using an excess of not more than 1.5 c.c. of concentrated 
hydrochloric acid in 100 c.c. of solution. Dilute to 200 
c.c. Precipitate the lead with hydrogen sulphide. Fil- 
ter, wash with H2S water, dissolve the PbS in hot dilute 
nitric acid, boil to expel HsS, add 10 c.c. of dilute HsSOt 
(1:1), evaporate to fumes of SOs and determine lead 
gravimetrically or volumetrically as outlined under 
"White Lead." 

Chromium. — Evaporate the alcoholic filtrate- from the 
PbS04 almost to dryness and mix with the filtrate from 
PbS. The chromium is determined by precipitating hot 
with a slight excess of ammonia. Filter, wash, ignite and 
weigh as Cr208. 

Zinc. — The filtrate from chromium hydroxid is ana- 
lyzed for zinc by precipitating with hydrogen sulphide: 
See "Zmc Oxid." 

Chrome Greens 

Preliminary Test. — Determine the presence of organic 
coloring matter by extraction with alcohol. 

Insohihle. — In a small evaporating dish heat i g. 
sami)le at as low a temperature as possible until the blue 
color is completely discharged. Transfer to a beaker, and 
boil with 20 c.c. of concentrated hydrochloric acid and a 
little alcohol to dissolve the soluble portion. Dilute with 
hot water, boil, filter, wash, and weigh the insoluble por- 
tion. Examine the latter for silica, clay or barytes. 

Lead. — Determine in the filtrate after neutralizing 
with ammonia and reacidifying slightly with hydro- 
chloric acid as under "Chrome Yellows." 



ANALYSIS OF PAINT MATERIALS 305 

Ckromiumy Iron and Aluminium. — Boil the filtrate from 
the lead sulphide to expel hydrogen sulphide, add a few 
drops of nitric acid and about 2 g. of ammonium chloride. 
Heat to boiling, and precipitate iron, aluminium, and 
chromium as hydroxids with ammonia in slight excess. 
Filter and wash the precipitates. Dissolve the mixed 
hydroxids in a small amount of hot dilute hydrochloric 
acid and dilute to 150 c.c. Heat to boiling and treat with 
an excess of sodium hydroxid, and bromine water. 
Filter and wash. Redissolve the ferric hydroxid in 
dilute hydrochloric acid, and determine iron by the usual 
methods. 

The filtrate is acidified faintly with hydrochloric acid 
and aluminium hydroxid precipitated with a slight excess 
of ammonia. 

The filtrate from aluminium hydroxid is carefully 
acidified with acetic acid, and the chromium precipitated 
by the addition of barium acetate to the hot solution. 
Allow to stand for some time, and filter through a Gooch 
or alundum crucible (using gentle suction). Wash with 
alcohol, and dry in hot closet. Finally ignite at a dull 
red heat by suspending the crucible inside a larger por- 
celain crucible by means of an asbestos ring. If desired 
the chromium present as alkali chromate may be reduced 
to chromic salt by evaporating with hydrochloric acid 
and alcohol. The chromium may then be precipitated 
by ammonia and weighed after ignition as Cr203. 

Calcium and Magnesium. — Determine as usual in the 
filtrate from iron, aluminium and chromium hydroxids. 

Sulphates. — Treat i g. as mentioned in the second 
paragraph of this section. Determine sulphates as under 
"Zinc Lead." 

Nitrogen. — Determine by the Kjeldahl-Gunning 
method. 



3o6 chemistry and technology of* paints 

Prussian Blue 

Hygroscopic Moisture. — Determine on a i g. sample 
by heating for 2 hours at 105*^ C. 

Water of Composition. — Determine by difference after 
the other constituents have been obtained. 

Ferrocyanic Acid.^ — Treat 0.5 g. with 10 c.c. of nor- 
mal, potassium hydroxid solution in a flask. Boil for 5 
minutes, dilute with 50 c.c. of hot water, filter, and 
wash the ferric hydroxid. 

The filtrate containing a solution of potassium fer- 
rocyanide is slightly acidified with sulphuric acid, 2 to 3 
g. of ammonium persulphate are added, and the liquid 
boiled from 20 to 30 minutes. Any blue color which 
persists is removed by the addition of hydrochloric acid 
and a little more persulphate. 

The iron is precipitated with ammonia by the usual 
method gravimetrically or volumetrically. Calculate as 
FeCcNfl. 

Cyanogen. — If desired, the total nitrogen in Prussian 
blue may be determined by the Kjeldahl-Gunning method 
as outlined in Bulletin 107, Bureau of Chemistrj^ U. S. 
Dept. of Agriculture. 

To determine the amount of Prussian blue, multiply 
the total iron content by 3.03 or nitrogen content by 4.4. 
The results thus obtained are fairly approximate. They 
are not exact since the composition of Prussian blue is 
variable. The pure Prussian blue should contain about 
20 per cent of nitrogen and 30 per cent of iron, and less 
than 7 per cent of moisture. The sulphuric acid used in 
determining the nitrogen by the Kjeldahl-Gunning method 
should not be blackened due to the presence of organic 
adulterants. 

* Ber. 1903, 36, 1929. 



ANALYSIS OF PAINT MATERIALS 307 

Iron. — To determine the total iron in Prussian blue, 
ignite i g. gently until the blue color is completely dis- 
charged. Dissolve the residue in lo c.c. of hydrochloric 
acid (i : i), filter, make up to loo c.c. in a graduated flask. 
Determine Fe208 in 50 c.c. in this solution (calculate to 
metallic iron). 

In the other 50 c.c. of the filtrate determine Fe203 + 
AI2O3 by the usual methods. Calculate AI2O3 by difference. 
Report as metallic aluminium. 

Calcium. — Determine as usual in the filtrate from 
Fe203 + AI2O3. 

Alkali Metals. — Determine by the usual methods. 

Analysis of Ultramarine 



The ultramarine is finely powdered and dried at 100°. 
2 to 10 g. are weighed off, digested with water, filtered, 
the filtrate diluted to 500 c.c, and 100 c.c. taken for each 
of the following determinations. 

(a) Na2S203 — determine with iodine solution and 
starch. Calculate to Na2S203 + Ag. 

(ft) Na2S04 — determine by precipitating with barium 
chloride in acid solution. 

{c) NaCl — determine by precipitating with AgNOs 
(NaCl is rarely present in ultramarine). 

10 to 20 grams of ultramarine are washed two or three 
times by decantation (to obtain a clear filtrate, alcohol is 
added). Evaporate almost to dryness with a dilute solu- 
tion of sodium sulphite ^ on the water bath. Wash until 
a test of the ultramarine moistened with water and fil- 
tered gives no trace of turbidity with barium chloride. 

^ In order to remove free S, for CS2 extracts only 40 to 60% 
of the same. 



3o8 CHEMISTRY A^D TECIIXOLOCY OF PAIXTS 

The ultramarine dried at 130 to 140° is again powdered 
and placed hot into a glass stoppered flask. 

II 

Estimation of silicic acid, silica, clay and total sulphur. 

I g. of the dried substance is weighed into a porcelain 
dish, stirred up with water and treated with i.to 2 c.c. of 
bromine. If it is partially dissolved (as shown by the yellow 
coloration of the liquid) 15 to 20 c.c. of nitric acid are added 
and the whole evaporated to dryness on the water bath. 

Take up with water, add 20 c.c. of hydrochloric acid 
and evaporate again (to remove nitric acid which would 
increase the BaS04 precipitate, and to render silicic acid 
insoluble). Treat with hydrochloric acid, digest warm 
for a few hours, dilute with water and filter. On the 
filter are left silicic acid and sand. 

To determine total sulphur, the filtrate is heated to 
boiling and precipitated with barium chloride. 

Ill 

Estimation of alumina and of soda. 

I g. of ultramarine, washed and dried as in number 
I, is carefullv mixed with water and treated with an ex- 
cess of hydrochloric acid. After standing for a while it 
is heated until the solution settles clear. It is then fil- 
tered, leaving sulphur, sand and silicic acid undissolved. 
The residue is weighed after ignition. The filtrate is 
evaj^orated to dryness, the residue moistened with water 
and hydrocloric acid and again dried. Take up with 
hydrochloric acid, dilute with water after standing for 
some time and filter. On the filter is left silicic acid, 
which, added to the residue obtained in the first filtra- 
tion, gives the content of total silicic acid and sand. The 
filtrate is evaporated to dryness to remove excess hydro- 



ANALYSIS OF PAINT MATERIALS 309 

chloric acid. The residue is dissolved in water, precipi- 
tated with ammonia and the whole thoroughly dried in 
the water bath. (This facilitates complete washing of 
the alumina.) / 

Take up the residue with hot water, add a few drops 
of ammonia, heat and filter. Alumina on the filter is 
determined and weighed. 

For determining soda, the filtrate is treated with sul- 
phuric acid and a little fuming nitric acid and evaporated 
to dryness. The residue is strongly ignited and the 
Na2S04 calculated to Na. 

Black Pigments 

(Carbon Black, Lampblack, Vine Black, Bone Black) 

Moisture. — Determine on a 2 g. sample by heating 
for two hours at 105° C. 

Volatile, — Heat for 10 minutes over a Bunsen flame 
in a well-covered porcelain crucible. 

Ash. — Determine on a i g. sample, ignite over a 
Bunsen burner with free access of air. When the ash is 
large in quantity, cool, moisten with a solution of ammo- 
nium carbonate and ignite again gently. 

Soluble and Insoluble Ash. — Treat the ash obtained 
by the above procedure with 5 to 10 c.c. of dilute hydro- 
chloric acid, heat, filter, wash and weigh the insoluble 
portion. Calculate the percentage of acid-soluble ash 
from the total ash and the acid-insoluble ash. 

Certain blacks are sometimes adulterated with Prus- 
sian blue. To detect the latter, boil with dilute caustic 
soda, filter, acidify the filtrate with dilute hydrochloric 
acid, and add a mixture of ferric chloride and ferrous 
sulphate. The formation of a blue precipitate indicates 
the presence of Prussian blue. 



3io chemistry ajftd technology of paints 

Graphite 

Heat I g. of the finely powdered graphite to a dull 
red heat and calculate the loss in weight as water. The 
dried substance is intimately mixed with 3 g. of a mixture 
of equivalent parts of K2CO3 and NasCOs and placed in a 
crucible, i g. of KOH or NaOH is sprinkled over the 
surface of this mixture and the whole heated slowly to 
redness. The mass fuses, swells and forms a crust on b^, 
which must be broken with a stout platinum wire. 

After fusing for one half hour, the melt is cooled, 
heated with water for J hour almost to boiling, filtered, 
washed well and the liquids set aside. The insoluble is 
dried, placed in a dish, the filter ash added and about 3 g. 
of HCl (specific gravity 1.18) poured in. After several 
minutes a slight gelatinization sets in due to the decom- 
position of the small residue of alkali silicate. The addi- 
tion of a little more hydrochloric acid brings the silicic 
acid into solution. After digestion for one hour, dilute 
with water, filter and wash out. The residue on the fil- 
ter is pure carbon, which, after drying and gentle ignition, 
is weighed. The acid filtrate is united with the alkaline 
one obtained above, more HCI added until weakly acid, 
evaporated to drj^ness, and silicic acid, alumina and iron 
oxid determined as usual. 

Blanc Fixe 

Water Soluble Salts, — Owing to the variety of methods 
emT)loycd in the technical production of blanc fixe, a 
prcliminar}' qualitative examination of the material is 
always essential before proceeding with the quantitative 
analysis. 

Digest about 5 g. with 150 c.c. of hot water and 
filter. Examine the filtrate to detect the presence of 



ANALYSIS OF PAINT MATERIALS 311 

water soluble salts. Determine the amount of water 
soluble salts, by difference, on a i g. sample. 

Acid Soluble. — Digest r g. of blanc fixe with hot water, 
wash by decantation and filter, keeping as much of the 
residue as possible in the beaker. Discard the filtrate 
and treat the residue in the beaker with about 25 c.c. of 
hot dilute HCl (1:3); filter through the filter paper used 
above, wash and ignite. Add i drop of nitric and 2 drops 
of sulphuric acid, evaporate, ignite again and weigh. Cal- 
culate % acid soluble from loss in weight, % water soluble 
and % moisture. 

BaS04. — Proceed as outlined below under barytes 
(fusion in platinum with Na2C03) to determine barium 
sulphate and silica (Page 314). 

Iron. — Determine colorimetrically. 

Silica. — To determine qualitatively ^ whether a sample 
of blanc &xe is free from silica or clay, heat about 0.5 g. 
with 10 to 15 c.c. of concentrated sulphuric acid. A pure 
blanc fixe or barytes dissolves completely. Silicious matter 
remains undissolved. Determine the amount of silicious 
matter on a i. g. sample by evaporating with a few c.c. 
of hydrofluoric acid and several drops of sulphuric acid. 

Analysis of Whiting 

Carbon Dioxid. — Determined as outlined under " White 
Lead.'' 

Calcium. — Determined by the usual methods. 

Gypsum or Calcium Sitlphate 

Calcium and Sulphates. — Determine by the usual 
methods. 

Moisture. — Dry 2 g. in a vacuum dessicator over 
sulphuric acid to constant weight. 

^ Method developed in the laboratory of Toch Brothers. 



312 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Combined H2O and Moisture. — Heat i g. in a covered 
porcelain crucible on an asbestos plate for 15 minutes, 
then heat the bottom of the crucible to dull redness for 
10 minutes over a Bunsen burner, remove the cover and 
heat for 30 minutes at a slightly lower temperature. 
Cool and weigh rapidly. 

Silica, Asbestine, Clay (Barytes) 

Hygroscopic Moisture. — Determine on a 2 g. sample 
by heating for i hour at 105° C. 

Loss on Ignition. — Determine on a i g. sample. This 
is largely water of composition, unless carbonates are 
present. 

Complete Analysis. — Mix 0.5 g. in a platinum crucible 
intimately with about 5 g. of anhydrous sodium car- 
bonate. Add a thin layer of the latter on top, cover 
the crucible and heat gently over a Tirrill or Tech burner 
for a short time. Raise the temperature gradually to 
the full heat of the burner. Finally heat for a short 
time over the blast lamp. Allow to cool, then heat the 
lower part of the crucible to dull redness, and cool again. 
Add a little water, heat carefully to boiling and the melt 
will readily separate from the crucible. Place the melt 
in an evaporating dish; wash the crucible with a little 
hot water, and add to the dish. If barytes, or blanc fixe 
is present, the melt is digested with hot water until 
com])letely disintegrated, the barium carbonate is fil- 
tered ofT and washed, and the barium determined as 
outlined under barium carbonate. The filtrate is then 
treated in a large covered beaker with concentrated 
hydrochloric acid. After a certain amount of acid has 
been added, the silicic acid separates out as a gelatinous 
mass, which has to be broken up in order to obtain inti- 
mate admixture with the acid. After an excess of acid 



ANALYSIS OF PAINT MATERIALS 313 

has been added, the solution is heated to boiling, trans- 
ferred to a porcelain or platinum dish and evaporated to 
dryness. 

It is essential that dehydration of the silica be carried 
out twice ^ at the temperature of the steam bath and that 
the insoluble silica be filtered off before evaporating the 
second time. 

Filter, wash, combine the insoluble residues from the 
two dehydrations, ignite in a platinum crucible and weigh. 
Drive off Si02 with a few c.c. of HF and several drops of 
H2SO4. Ignite and reweigh. The loss in weight is silica. 

Iron and Aluminium Oxids. — Treat the filtrate from 
the silicic acid with a few drops of concentrated nitric 
acid and lo to 20 c.c. of a cold saturated solution of 
ammonium chloride. Heat to boiling and precipitate 
with a slight excess of ammonia. Allow the precipitate 
to settle, filter off the clear liquid and wash twice by 
decantation with hot water. Redissolve the ferric and 
aluminium hydroxids by running hot dilute hydrochloric 
acid through the filter paper into the beaker containing 
the major portion of the precipitate. Reprecipitate with 
ammonia, as before, filter, wash and ignite wet in the 
platinum crucible containing the residue obtained after 
Si02 was volatilized with HF and H2SO4. Weigh as 
FeaOs + AI2O3. 

For the determination of iron in the mixed oxids, sae 
Treadwell and Hall, Vol. II, p. 109. 

Calcium. — Evaporate the filtrates from the ferric and 
aluminium hydroxids to a small volume. Heat to boil- 
ing and precipitate with a boiling solution of ammonium 
oxalate. Allow to stand for several hours. Filter and 
wash. Puncture the filter paper with a glass rod, wash the 
precipitate into a beaker with a stream of water from the 

^ Hillebrand, "Analysis of Silicate and Carbonate Rocks." 



314 CHEMISTRY AND TECHNOLOGY OF PAINTS 

wash bottle, and pass 20 c.c. of hot .dilute sulphuric acid 
(1:1) over and through the filter paper. . Heat to 90® C. 
and titrate with N/io KMn04. 

Magnesium. — Evaporate the filtrate from the calcium 
oxalate to dryness, and ignite in a porcelain dish. Moisten 
the residue with a little concentrated hydrochloric acid 
and dissolve in hot water. Filter and determine mag- 
nesium in the filtrate. Heat to boiling and treat with an 
excess of sodium or anunonium phosphate. Add an 
amount of 10 per cent ammonia equal to | of the volume of 
solution. AUow to cool and set aside for a few hours. 
Filter through an alundum crucible, wash with 2.5 per cent 
ammonia, dry, ignite slowly at first and finally strongly 
until the precipitate is white. Weigh as MgiPjOi. 

Alkalies. — See J. Lawrence Smith (Bulletin 422, U. 
S. Geologic Survey). 

Barytes 

Make a preliminary test for lead compounds. In 
the absence of the latter weigh ofiF i g. sample and mix 
with 5 g. anhydrous sodium carbonate in a platinum 
crucible. Fuse over the blast lamp for a half hour, occa- 
sionally imparting a rotary motion to the crucible to 
insure thorough reaction. Allow to cool, then heat the 
lower part of the crucible to dull redness, and cool again. 
Add a little water, bring carefully to boil, and the melt 
will readily separate from the crucible. Place in an 
evaporating dish, add 100 c.c. of water, and digest on 
the steam bath until com])letely disintegrated. Filter 
and wash the insoluble residue (BaCOs) until free from 
soluble salts. Dissolve the BaCOa with 25 c.c. of hydro- 
chloric acid (1:3), catching the filtrate and passing it 
through the filter to insure complete solution of the 
barium carbonate. Boil to expel carbon dioxid, neu- 



^i^ALYSIS OF PAINT MATERIALS 315 

tralize the filtrate with ammonia, reacidify with a few 
drops of hydrochloric acid, heat to boiling, and precipi- 
tate with dilute sulphuric acid. Filter and wash on a 
Gooch crucible, dry at 130° C. and report as BaS04. 

In the presence of lead, first extract the barytes with 
hot concentrated ammoniimi acetate solution before 
proceeding with the sodium carbonate fusion, since the 
presence of metallic lead in the fusion will ruin the 
platinum crucible. 

Iron. — Determine colorimetrically . 

Clay and Silica. — Acidify the filtrate from the barium 
carbonate with hydrochloric acid, evaporate to dryness 
on the steam bath, heat for 20 minutes longer on the 
steam bath, and extract with hot water and a little 
hydrochloric acid. Filter, wash and weigh the insoluble 
Si02. Determine alumina in the filtrate from Si02 as 
usual. See also determination of silica in blanc fixe 

(p. 311). 

In reporting the presence of silica and alumina, it 

must be remembered that the reagents used in the above 
determination, sodium carbonate and ammonia, almost 
always contain appreciable quantities of silica and alu- 
mina. Especially is this true of aqua ammonia, except 
when kept in bottles lined with ceresin or paraffin wax. 

Analysis of Barium Carbonate 

Water Soluble Sails. — Determine by difference in a i 
g. sample, treat with hot water, filter, wash, and weigh 
the insoluble. 

Insoluble. — - Dissolve about 10 g. in dilute hydro- 
chloric acid. Heat to boiling, filter, wash and weigh 
the insoluble residue. The latter is generally silicious, 
but should be examined to determine the presence of 
barium. 



3l6 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Barium. — Dissolve 0.5 g. in dilute hydrochloric acid, 
neutralize with ammonia, then reacidify faintly with 
hydrochloric acid. Dilute to 100 ex., heat to boiling, 
and precipitate with hot dilute sulphuric acid. Filter on 
a Gooch crucible, wash, and dry at 130° C. Calculate 
BaS04 to BaCOs. For the separation of barium, cal- 
cium, and strontium from each other, see Treadwell and 
Hall, Anal. Chem., Vol. II, p. 79. 

Carbon Dioxid. — Determine by evolution as outlined 
under "White Lead." 

Iron.^ — Treat 2 g. in a beaker with 15 c.c. of water 
and sufficient nitric acid to dissolve the barium carbonate. 
Boil for several minutes to expel carbon dioxid and to 
convert all the iron to the ferric state. Filter and 
wash the residue. Cool the filtrate, neutralize with 
ammonia and acidify faintly with nitric acid. 

Wash the contents of the beaker into a 100 c.c. 
Nessler cylinder, add 15 c.c. of dilute ammonium thio- 
cyanate (1:20) and dilute to the mark. The depth of the 
blood red color developed is a measure of the amount of 
iron present. Compare with a blank made as follows: 

Prepare a standard solution of ferric ammonium sul- 
phate by dissolving 0.7022 g. of ferrous ammonium sul- 
phate in water. Acidify with sulphuric acid, heat to 
boiling and oxidize the iron by the addition of a solu- 
tion of potassium permanganate. Only the faintest 
excess of permanganate should be added. The faint pink 
tinge due to the latter soon disappears. The solution is 
cooled and diluted to i liter. One c.c. of this solution 
is equivalent to o.oooi g. of iron. 

Into a 100 c.c. Nessler cylinder add about the same 
amount of nitric acid as was used to dissolve the barium 

^ Modified Thompson & SchacfTcr method. J. Ind. Eng. Chem. 
1912, 659. 



ANALYSIS OF PAINT MATERIALS 317 

carbonate, and 15 c.c. of ammonium thiocyanate solution. 
Dilute to 100 c.c. and add the standard ferric ammonium 
sulphate solution, drop by drop, until the color exactly 
matches that developed in the sample being tested. 
One c.c. of the solution is equivalent to o.oi per cent 
iron when a i g. sample is used. Not more than 
2 or 3 c.c. of the standard should be required to equal 
the color; otherwise, the color becomes too deep for 
comparison. 

Sulphur . — For colorimetric determination see Tread- 
well & Hall, Vol. II, pages 354-7. 

Chlorine. — Determine in the water soluble portion 
(acidified with nitric acid) by precipitating hot in the 
presence of a slight excess of silver nitrate, filter on a 
Gooch or aluridum crucible, wash, and weigh the insoluble 
AgCl after drying at 130° C. 

Analysis of Mixed White Paints 

I. By use of Acetic Acid 

Treat i g. of the mixed white pigment with 22 c.c. of 
water and 10 c.c. of glacial acetic acid. Boil, filter, and 
wash with water. The filtrate is heated to boiling, and 
precipitated with hydrogen sulphide. Filter off the lead 
and zinc sulphides, dissolve in hot dilute nitric acid, and 
determine lead and zinc as usual. Calculate the lead to 
white lead, and zinc to oxid. The filtrate from lead and 
zinc sulphides is tested for Ba, Ca, and Mg. Determine 
and calculate to carbonates. 

To the residue from the acetic acid treatment add 
10 c.c. of water, 10 c.c. of strong hydrochloric acid, and 
5 g. ammonium chloride. Heat on steam bath for 5 
minutes, dilute with boiling water to 400 c.c, boil, filter, 
wash, ignite and weigh the insoluble. Examine for 
silica, clay, barytes or asbestine. 



3i8 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Precipitate the lead in the filtrate with hydrogen sul- 
phide, filter and wash. Dissolve in hot dilute nitric acid, 
and determine as usual. Report as PbS04. The fil- 
trate is boiled to expel hydrogen sulphide, a few drops 
of nitric acid, ammonium chloride, and anmtionia in excess 
are added to precipitate iron and aluminium. Calcium 
is determined in the filtrate as usual. Report as CaSOf. 

II. By G. W. Thompson, {Jour. Soc. Chem, Ind. i§, 4J2) 

"The qualitative examination for the elements pres- 
ent may be determined as follows: Effervescence with 
concentrated hydrochloric acid indicates carbonic acid, 
sulphuretted hydrogen if zinc sulphide is present, or sul- 
phurous acid if lead sulphite is present. These latter 
two may be recognized by their odors. Boil a portion 
of the paint with acid ammonium acetate and test a 
portion of the filtrate for sulphuric acid with barium 
chloride. Test another portion of the same solution 
with sulphuric acid in excess for lead and test filtrate 
for zinc by making alkaUne with ammonia, and adding 
ammonium sulphide. Test another portion of the am- 
monium acetate solution for lime by making alkaline 
with ammonia, adding ammonium sulphide, filtering and 
adding ammonium oxalate to filtrate. The portion 
insoluble in ammonium acetate, in the absence of sul- 
phite of zinc and sulphate of lead may be barytes, China 
clay, or silica. The qualitative examination of this 
residue is best combined with quantitative examination 
given further on.'' 

'*The oxids and elements, the presence of which is 
usually possible in a white paint, are: carbonic acid, 
water (combined), sulphuric acid, sulphurous acid, sulphur 
(combined as sulphide), silica, barium oxid, calcium 
oxid, zinc oxid, and zinc combined as sulphide, lead 
oxid, aluminium oxid." 



ANALYSIS OF PAINT MATERIALS . 319 

"In the absence of sulphuric acid^ the lead soluble in 
acetic acid may be directly calculated to white lead." 

"Sulphuric acid may exist in two conditions, in one 
it is soluble in ammonium acetate, and in the other, as 
in barytes, it is insoluble in ammonium acetate. That 
soluble in ammonium acetate may be determined by 
precipitating with barium chloride in that solution. 
Sulphuric acid in barytes is best calculated from the 
barium present, and determined as described later on. 
Sulphurous acid may be determined by oxidation to sul- 
phuric acid, or its determination may be based on the 
insolubility of lead sulphite in ammonium acetate. For 
instance, one portion of the sample is oxidized with 
nitric acid and the total lead determined. Another 
portion is treated directly with ammonium acetate, and 
the lead soluble in that menstruum determined. The 
diflFerence between the two determinations is the lead 
present as sulphite, from which we may calculate the 
sulphurous acid present. Sulphur as sulphide is always 
present as zinc sulphide, which is never used in the 
presence of lead compounds. It may be determined by 
oxidation with bromine water and precipitation with 
barium chloride, or by determining the zinc insoluble 
in ammonium acetate. Silica may be determined by 
treating the matter insoluble in ammonium acetate with 
hydrofluoric acid and sulphuric acid. The loss on 
ignition is silica, or it may be determined by fusing the 
residue in the regular way. Barium oxid is determined 
by precipitation with sulphuric acid from hydrochloric 
acid solution of that part of fused residue insoluble in 
water." 

Rapid Methods for White Pigments 

"Sample i is a mixture of barytes, white lead, and 
zinc oxid. 



320 CHEMISTRY AND TECHNOLOGY OF PAINTS 

"Two i-gram portions are weighed out. One is 
dissolved in acetic acid and filtered, the insoluble matter 
ignited and weighed as barytes, the lead in the soluble 
portion precipitated with dichromate of potash, weighed 
in Gooch crucible as chromate, and calculated to white 
lead. 

"The other portion is dissolved in dilute nitric acid, 
sulphuric acid added in excess, evaporation carried to 
fumes, water added, the zinc sulphate solution filtered 
from barytes and lead sulphate and precipitated directly 
as carbonate, filtered, ignited, and weighed as oxid. 

"Sample 2 is a mixture of barytes and so-called sub- 
limed white lead. 

"Weigh out three i-gram portions. In one determine 
zinc oxid as in Case i. Treat a second portion with 
boiling acetic acid, filter, determine lead in filtrate and 
calculate to lead oxid. Treat third portion by boiling 
with acid ammonium acetate, filter, ignite, and weigh 
residue as barj^tes, determine total lead in filtrate, deduct 
from it the lead as oxid, and calculate the remainder 
to sulphate. Sublimed lead contains no hydrate of lead, 
and its relative whiteness is probably due to the oxid of 
lead being combined with the sulphate as basic sulphate. 
Its analysis should be reported in terms of sulphate of 
lead, oxid of lead, and oxid of zinc. 

"Sample 3 is a mixture of barytes, sublimed lead, and 
white lead. 

"Determine barj'tes, zinc oxid, lead soluble in acetic 
acid and in ammonium acetate, as in Case 2; also deter- 
mine carbonic acid, which calculate to white lead, deduct 
lead in white lead from the lead soluble in acetic acid, and 
calculate the remainder to lead oxid. 

"Sample 4 is a mixture of barytes, white lead, and 
carbonate of lime. 



ANALYSIS OF PAINT MATERIALS 321 

"Determine barj^tes and lead soluble in acetic acid 
(white lead) as in Case i. In filtrate from lead chromate 
precipitate lime as oxalate, weigh as sulphate, and cal- 
culate to carbonate. Chromic acid does not interfere 
with the precipitation of lime as oxalate from acetic acid 
solution. 

'^Sample 5 is a mixture of barytes, white lead, zinc 
oxid, and carbonate of lime. 

"Determine barytes and white lead as in Case i. 
Dissolve another portion in acetic acid, filter and pass 
sulphuretted hydrogen through the boiling solution, filter, 
and precipitate lime in filtrate as oxalate; dissolve mixed 
sulphides of lead and zinc in dilute nitric acid, evaporate 
to fumes with sulphuric acid, separate, and determine 
zinc oxid as in Case i. 

"Sample 6 is a mixture of barytes, white lead, sub- 
limed lead, and carbonate of lime. 

"Determine barytes, lead soluble in acetic acid and in 
ammonium acetate, as in Case 2, lime and zinc oxid, as 
in Case 5, and carbonic acid. Calculate lime to car- 
bonate of lime, deduct carbonic acid in it from total 
carbonic acid, calculate the remainder of it to white lead, 
deduct lead in white lead from lead soluble in acetic acid, 
and calculate the remainder to oxid of lead. 

"Sample 7 contains sulphate of lime. 

"Analyses of paints containing sulphate of lime 
present peculiar difficulties from its proneness to give 
up sulphuric acid to lead oxid if white lead is present. 
Sulphate of lime and white lead boiled in water are more 
or less mutually decomposed with the formation of sul- 
phate of lead and carbonate of lime. A method for the 
determination of sulphate of lime is by prolonged washing 
with water with slight suction in a weighed Gooch 
crucible. This is exceedingly tedious, but thoroughly 



52J CHEMISTRY AXD TECHSOLOGY OF PAJSTS 

accurate. A reservpir containing water may be placed 
above the crucible, and the water allowed to drop slowly 
into it. This may take one or two days to bring the 
Siunple to constant weight, during which time several 
liters of water will have passed through the crucible. 
Another method for separating the sulphate of lime is 
by treatment in a weighed Gooch crucible with a mixture 
of nine jxirts of 95 per cent alcohol and one part of 
glacial acetic acid. Acetates of lead, zinc, and lime being 
sohible in this mixture, the residue contains all the sul- 
phate of lime and any sulphate of lead and barytes which 
may be present. Determine the lead and lime as in 
s;\mple 4, and calculate to sulphates. Sulphate of lime 
should be fully hydrated in paints. To determine this, 
obtain loss on ignition; deduct carbonic acid and water 
in other constituents; the remainder should agree fairly 
well with the calculated water in the hydrated sulphate 
of lime, if it is fully hydrated. If, after washing a small 
portion of the sample with water, the residue shows no 
sulphuric acid soluble in ammonium acetate, the sulphate 
oi lime may bo obtained by determining the sulphuric 
;uid soluble in ammonium acetate and calculating to 
sulphate oi lime. The dilTiculty is in determining the sul- 
pluilc of lime in the presence, or possible presence, of 
sulphate oi lead. To illustrate the analysis of sample of 
w hilc paint contaiuing sulphate of lime and the difliculty 
atlciuling thereon, wc would mention a sample containing 
suhlimed lead, while lead, carbonate of lime, and sulphate 
o\ lime. In such a samj^le we would determine the 
lead, lime, sulphuric acid, carbonic acid, loss on ignition, 
the portion soluble in water, and the lime or sulphuric 
acid in that portion, calculating to sulphate of lime. 
Deduct the lime in the sulphate of lime from the total 
lime, and calculate the remainder to carbonate of lime; 



ANALYSIS OF PAINT MATERIALS 323 

deduct the carbonic acid in the carbonate of lime from 
the total carbonic acid, and calculate the remainder to 
white lead; deduct the sulphuric acid in the sulphate of 
lime from the total sulphuric acid, and calculate the 
remainder to sulphate of lead. The lead unaccounted for 
as sulphate or white lead is present as oxid of lead. 
Deduct the carbonic acid and water in the carbonate of 
lime and white lead from the loss on ignition, the re- 
mainder being the water of hydration of the sulphate of 
lime. 

*^ Sample 8 contains as insoluble matter, barytes, 
China clay and silica. 

'* After igniting and weighing the insoluble matter, 
carbonate of soda is added to it, and the mixture fused. 
The fused mass is treated with water, and the insoluble 
portion filtered off and washed. This insoluble portion 
is dissolved in dilute hydrochloric acid, and the barium 
present precipitated with sulphuric acid in excess. The 
barium sulphate is filtered out, ignited, weighed, and if 
this weight does not differ materially — say by 2 per 
cent, — from the weight of the total insoluble matter, 
the total insoluble matter is reported as barytes. If the 
difference is greater than this, add the filtrate from the 
barium sulphate precipitate to the water-soluble portion 
of fusion. Evaporate and determine the silica and the 
alumina in the regular way. Calculate the alumina to 
China clay on the arbitrary formula 2SiOi. AI2O3. 2H2O, 
and deduct the silica in it from the total silica, reporting 
the latter in a free state. It is to be borne in mind that 
China clay gives a loss of about 13 per cent on ignition, 
which must be allowed for. China clay is but slightly 
used in white paints as compared with barytes and 
silica." 

"Sample 9 contains sulphide of zinc. 



324 CHEMISTRY AND TECHNOLOGY OF PAINTS 

'^Samples of this character are usually mixtures in 
var>'ing proportions of barium sulphate, sulphide of zinc, 
and oxid of zinc. Determine barytes as matter insolu- 
ble in nitric acid, the total zinc as in Case i, and the zinc 
soluble in acetic acid, which is oxid of zinc. Calculate 
the zinc insoluble in acetic acid to sulphide." 

"Sample lo contains sulphite of lead. 

"This is of rare occurrence. Sulphite of lead is in- 
soluble in ammonium acetate, and may be filtered out 
and weighed as such. It is apt on exposure to the air in 
the moist state to become oxidized to sulphate of lead. 

"There are certain positions which the chemist must 
take in reporting analyses of white paints: 

^^ First. White lead is not uniformly of the composition 
usually given as theoretical 2PbC0j- Pb(OH)i, but in 
reporting we must accept this as the basis of calculating 
results, unless it is demonstrated that the composition of 
the white lead is very abnormal. 

^^ Second. In reporting oxid of lead present this 
should not be done except in the presence of sulphate of 
lead, and if white lead is present, then only where the 
oxid is more than i per cent; otherwise calculate all 
the lead soluble in acetic acid to white lead. 

" ThiriL China clav is to be calculated to the arbi- 
trar>' formula given. 

"In outlining the above methods we have in mind 
many sami)les that we have analyzed, and the combinations 
we have chosen are those we have actually found present." 

Analysis of Paints 

Separation -of Pigment from Vehicle. — The can of paint 
is weighed off and if free from water, heated on the steam 
bath for 1 5 to 30 minutes. Owing to the marked decrease 
in the s])ecific gravity and the viscosity of the i)aint 



ANALYSIS OF PAINT MATERIALS 325 

vehicle at the higher temperature, the pigment generally 
settles to the bottom very quickly. 

In the case of paints which show the presence of 
water, it is best to allow the pigment to settle out in 
the cold in order to avoid any saponifying action which 
the pigment might exert on the vehicle. The clear 
liquid is then drawn off as far as possible and set 
aside for analysis. The can is carefully wiped and 
weighed again. 

About 25 g. of the residue in the can are weighed 
into a tall weighing tube. A mixture of benzol and 
alcohol 1:1 is added and the contents carefully stirred 
up with a glass rod. Another tube containing a similar 
weighed quantity of the same material is balanced to 
within 0.1 of a gram against the first tube, after adding 
the solvent and stirring. 

The two are then placed in the opposite receivers of a 
centrifuge and whirled at a moderate or high speed, 
(depending upon the facility with which the pigment set- 
tles out) for about five or ten minutes. The clear liquid 
is then drawn off, the tubes balanced, and after the 
addition of fresh solvent, stirred and again centrifuged. 
This is continued until no more of the vehicle can be 
extracted. 

The tubes are then placed in an air oven first at 80° 
C. and then at 100° C. until dry. From the weights of 
the tubes before and after extraction, the weight of paint 
extracted, and the weights of the can with and without 
the supernatant liquid, the percentage of vehicle and 
pigment can be calculated. 

There is generally left with the extracted pigment a 
small percentage of unextracted matter (probably soaps 
resulting from the interaction of pigment and vehicle, 
or linoxyn), for which allowance must be made. 



326 CHEMISTRY AND TECHNOLOGY OF PAINTS 

The extracted pigment is analyzed as outlined in the 
chapter on "Methods of Analysis of Pigments." 

Determination of Volatile Matter.^ — Weigh oflF into a 
round bottomed flask, 50 to 75 g. of the ready mixed 
paint. Connect with a condenser by means of a steam 
trap. Pass live steam through until no more of the 
volatile oil comes over. Allow the distillate to separate 
from the water and analyze separately. Shut oflF the 
steam and drive air through the apparatus. At the same 
time, heat the contents of the flask to 130° C. The 
residue is analyzed for non-volatile oils. Acetone, if 
present, will be- found in the aqueous as well as oily 
layers of the distillate. 

. Analysis of Non-volatile Portion Extracted from the 
Ready Mixed Paint, as Previously Outlined. — As a rule, 
very little information can be obtained, in the present 
state of our knowledge of this subject, from the analysis 
of a varnish or the non- volatile portions of a paint vehicle. 

Most of the constants or characteristics of the various 
ingredients which go to make up the varnish are so altered 
in the process of cooking that it is often extremely difficult, 
if not impossible, to distinguish them in the final material. 

Rosin can generally be determined qualitatively and 
quite often, quantitatively, but even here it is some- 
times impossible to detect it in admixture with other 
varnish resins. 

Determination of Rosin 

(Tu^tcheU Method) ^ 

Fatty or aliphatic acids are converted into ethyl 
esters when acted upon by hydrochloric acid gas in their 

' Amer. Soc. Testinjr Mat. Report t)f Comm. on Preservative 
Coatings for Structural Materials, 190^^-1913. 
- J. Soc. Chem. Ind. 1891, 10, 804. 



ANALYSIS OF PAINT MATERIALS 327 

alcoholic solution; rosin acids undergo little or no change, 
abietic acid separating from the solution. 

Weigh oflf 2 .to 3 g. of the mixed fatty or rosin acids 
in a flask, dissolve in 10 volumes of absolute alcohol and 
pass a current of dry, hydrochloric acid gas through the 
solution, the flask being kept cool by immersion in cold 
water. After about 45 minutes the reaction is complete, 
when unabsorbed HCl gas escapes. 

The flask is allowed to stand for one hour to permit 
complete esterification and separation of the ethyl esters 
and rosin acids. Dilute the contents of the flask with 
five times its volume of water and boil until the aqueous 
solution has become clear. 

Gravimetric Method. — Mix the contents of the flask 
with a little petroleum ether (b.p. below 80°) and trans- 
fer to a separatory funnel. The flask is washed out with 
the same solvent. The petroleum ether layer should be 
about 50 c.c. in volume. 

After shaking, the acid solution is removed, the 
petroleum ether layer washed once with water, then 
treated in the same funnel with 45 c.c. N/5 KOH and 5 
c.c. of alcohol. The liquids in the funnel then separate 
into: 1° a petroleum ether solution floating on top, and 
2° an aqueous solution containing rosin soap. The 
soap solution is run off, the rosin esters liberated by 
decomposition with dilute hydrochloric acid, dissolved in 
ether, and separated by evaporating the solvent on the 
steam bath. 

Volumetric Method. — The acidified mixture is poured 
into a separatory funnel and the flask washed a few 
times with ether. The mixture is thoroughly agitated, 
then allowed to separate, the acid layer run out, and the 
remaining ethereal solution containing the mixed ethyl 
esters and rosin acids washed with water until free from 



328 CHEMISTRY AND TECHNOLOGY OF PAINTS 

hydrochloric acid. 50 c.c of alcohol is then added and the 
solution titrated with standard alkali, using phenolphthalein 
as indicator. The rosin acids react immediately, forming 
rosin soaps; the ethyl esters remain unaffected. 

The number of c.c. of N alkali is multiplied by 0.346, 
giving the amoimt of rosin acids in the sample. 

The gravimetric method is the more accurate one, due 
to the difference in combining weights of the rosin acids 
in different samples of rosin. The results obtained by 
the Twitchell method are only approximately accurate. 

In the case of a mixture of rosin acids, fatty and un- 
sap>onifiable, saponify with alcoholic KOH and drive 
off the alcohol (after dilution with water) by continued 
boiling. Disregarding the undissolved unsaponifiable, 
the aqueous soap solution is transferred to a separatory 
funnel and shaken out with petroleum ether; this removes 
the unsaponifiable. On treating with mineral acids, the 
soap solution yields a mixture of rosin and fatty acids 
which are separated by the Twitchell process. 

In the volumetric method, the unsaponifiable need 
not be separated as above. 2 g. of the mixed acids 
and unsaponifiable are weighed off accurately, titrated 
with N alkali and the number of c.c. (a) noted. Another 
2 g. are treated with HCl gas and titrated with N alkali, 
using (b) c.c; taking 346 as the combining weight for 
rosin and 275 for the fatty acids (palmitic, stearic and 
oleic), the weight of the rosin acids is b X 0.346; the weight 
of fatty acids is (a — b) X 0.275, and the weight of the un- 
saponifiable equals 100 — {b X0.346 + (a — b) X 0.275} . 

Separation of Rosin Acids from Fatty. — After the 
esterification process, we get a mixture of free acid and 
esters, and after titration (e.g. in the volumetric process) 
we get a mixture of rosin soap and ethyl esters of fatty 
acids. If the alcohol is distilled off and the remaining 



ANALYSIS OF PAINT MATERIALS 329 

mixture treated with water, the soap is dissolved, leaving 
the esters floating on top of the soap solution. The 
two layers are separated and the soap solution, after 
washing with ether to remove traces of esters, yields 
rosin acids on acidulating. The ethyl esters are saponi- 
fied by caustic alkali and the fatty acids separated. 

Determination of Rosin 

(Woljf dr Scholze Method) ' 

Quick Titrimetric Determination. — 2 to 5 g. of the 
rosin — fatty — acid mixture, according to the quantity 
weighed off, are dissolved in 10 to 20 c.c. of absolute 
methyl or ethyl alcohol, treated with 5 to 10 c.c. of a 
solution of one part of sulphuric acid in four parts 
alcohol (methyl or ethyl) and boiled for two minutes 
wth reflux condenser. 

The reaction liquid is then treated with 5 to 10 volumes 
of 7 to 10 per cent sodium chloride solution and the fatty 
acid esters together with the rosin acids extracted with ether 
or a mixture of ether and a little petroleum ether. The 
aqueous solution is drawn off and agitated once or twice 
with ether. The ethereal solutions are united, washed 
twice with dilute sodium chloride solution (or when the 
washed water is not neutral, to neutrality), and after 
the addition of alcohol, titrated with N/2 KOH. 

Assuming an average of 1 60 as the acid value of the 
rosin acids and a correction for unsaponifiable fatty acids 
of 1.5, and further taking "m'' as the amount of the 
weighed fatty — acid — rosin mixture and "a" as the 
number of c.c. of KOH used for neutralization, we obtain 
as the rosin acid content in per cent, the following: 

a. 17. 76 

— ^ ^-5 

m 

1 Chem. Ztg. 7,^ (igu), 369, 382. 



330 CHEMISTRY AND TECHNOLOGY OF PAINTS 

The amount of rosin is approximately obtained. by 
multiplying this value by 1.07. 

Gravimetric. — 2 to 5 g. of the fatty acid mixture 
are treated as in the first method. After neutraliza- 
tion, I to 2 c.c. more of alcoholic KOH are added 
and the ethereal solution repeatedly washed with water. 
The wash water and soap solution are concentrated to a 
small volume, transferred to a separatory funnel, acidi- 
fied, and after the addition of the same amoimt of sodium 
chloride solution, extracted two to three times. The 
ethereal solution is dried with fused sodium sulphate and 
the ether distilled off in a small flask. 

The residue on cooling is dissolved in 10 c.c. of 
absolute ethyl alcohol, and 5 c.c. of a mixture of i part 
sulphuric acid with 0.4 parts alcohol are added. The 
mixture is allowed to stand for i^ to 2 hours at 
room temperature. It is then treated with 7 to 10 volumes 
of 10 per cent sodium chloride solution, extracted with 
ether two to three times, and the united ether extracts 
(after twice washing with dilute sodium chloride and 
drying with fused sodium sulphate) distilled off. 

The percentage of the thus isolated rosin acids may be 
multiplied by 1.07 in order to yield approximately the 
rosin content. 

Rosin and Rosin Oils 

LicbermanU'Storch Reaction, — Dissolve the washed and 
dried mixed acids (obtained by saponification of the 
material to be analyzed and liberating the acids with 
dilute hydrochloric or sulphuric acid) in acetic anhydride 
on the water bath, cool and add a few drops of sulphuric 
acid (specific gravity 1.53). 

This acid is made by mixing 34.7 c.c. of concentrated 
sulphuric acid with 35.7 c.c. of water, yielding 62.53 



ANALYSIS OF PAINT MATERIALS 331 

per cent sulphuric acid. The presence of rosin or rosin 
oil is detected by a very fine reddish violet coloration 
produced on the addition of the acid. 

Detection. — Rosin oil may be detected by the Lie- 
bermann-Storch reaction already mentioned, or by the 
following : ^ 

Stannic bromide is prepared by adding bromine drop- 
wise to granulated tin in a dry flask immersed in cold 
water until an excess is present. Then a little more 
bromine is added and the whole diluted with three to 
four volumes of carbon disulphide. The reagent thus 
obtained is stable. 

To carry out the test, a few drops of the rosin oil are 
placed in a dry test tube and dissolved in i . c.c. of car- 
bon disulphide. Add the stannic bromide reagent grad- 
ually. If rosin oil is present, the liquid assumes an 
intense, brilliant, violet coloration. 

It may be necessary to dilute with more carbon disul- 
phide in order to bring out this color. 

On standing, a violet sediment is formed in the tube 
from which, after removing the liquid and warming the 
residue with carbon disulphide, the purple coloration 
is again obtained free from impurities. 

In the presence of much mineral oil, mix the sample 
with the solution of stannic bromide in carbon disulphide, 
and then add, drop by drop, a solution of bromine and 
carbon disulphide. This yields the coloration unmasked 
by any due to the mineral oil. 

. Rosin Oil 

Rosin Spirit. — This is the lighter and more volatile 
portion obtained in the dry distillation of rosin. It is 
separated from the aqueous acetic acid layer, purified with 

^ Allen, "Commercial Organic Analysis.^' 



332 CHEMISTRY AND TECHNOLOGY OF PAINTS 

sulphuric acid and caustic soda, and then re-distilled. 
It is insoluble in water or alcohol, but soluble, in all pro- 
portions, in ether, petroleum-ether and turpentine. The 
specific gravity varies from 0.856 to 0.883. 

Composition. — The hydro-carbons,^ of which this is 
principally composed, include pentane and pentene and 
their homologues, toluene and its homologues, tetra and 
hexahydrotoluene and their homologues, terpenes, etc. 
The characteristic constituent of rosin spirit is hep- 
tine, C7H12, (methyl-propyl-allene). The compound boils 
at 103° to 104° C, and has a specific gravity of 0.8031 
at 20° C. It is soluble in alcohol and ether, absorbs 
oxygen very readily, but does not affect ammoniacal 
cuprous chloride or silver nitrate. 

Rosin Oil. — This is the heavier and less volatile por- 
tion obtained after the rosin spirit has been collected. 
It generally has a strong fluorescence although the lat- 
ter can be more or less destroyed by hydrogen i>eroxid, 
the addition of nitro-benzol, nitro- or dinitrotoluene, 
dinitronaphthalene, or by heating with sulphur. The 
specific gravity of the crude rosin oil varies from 0.96 
to I.I while the refined generally has a specific gravity 
of 0.97 to 0.99. 

Determination of Water 

Qualitative. — Water in an oil, paint, dryer or varnish 
may be detected by adding a few c.c. of dry mineral oil 
to an equal quantity of the sample in a test tube and 
shaking vigorously with a few grains of a strong dye like 
er\'throsine, rhodamine or methylene blue. Coloration 
proves the presence of water. Solvents like alcohol, 
acetone or amyl acetate which dissolve these dyes must 
of course be absent. 

* Rcnard, Amer. Chcm. Phys. 1884 (6) i, 323. 



ANALYSIS OF PAINT MATERIALS 333 

The presence of an appreciable quantity of water in 
an oil is indicated by the crackling produced when some 
of it is heated in a test tube beyond 212° F. 

Quantitative. — (i) In the case of non-volatile oils, about 
5 g. are accurately weighed into a small evaporating dish 
or watch-glass and dried in the air oven at 100-110° C. 
for two hours. The loss in weight (except where volatile 
fatty acids are present) is reported as moisture. 

For accurate determinations, however, the above 
method is open to serious objection. In the case of soya 
bean oil, for example, owing to its comparatively high 
content of volatile acids and glycerides, the results 
obtained may be somewhat high; whereas in the case of 
linseed oil the loss due to moisture may be more than 
counter-balanced by the gain in weight due to oxidation. 

With drying oils, the following method^ is therefore 
recommended : 

(2) A small Erlenmeyer flask fitted with a cork 
through which pass two tubes, a long tube reaching down 
to the bottom of the flask and a short one ending just 
below the cork, is carefully dried and weighed. 5 g. of 
oil are then introduced, the flask placed upon a steam 
bath, and dry carbon dioxid, hydrogen or coal-gas 
passed through the oil for i or 2 hours by connecting the 
short tube to an air pump or aspirator. The flask is then 
carefully dried and weighed. 

(3) For the determination of water in oils like pine 
oil, which always contain an appreciable quantity of 
water, as well as in ready mixed paints, the method ^ 
outlined on the next page is very useful: 

^ Determination of moisture in oils in a current of air — Son- 
nenschein-Zeit. anal. Chem. 25, 373. J. Soc. Chem. Ind. 1886, 
508. 

- Michel, Chem. Ztg., 1913, 353. 



334 CHEMISTRY AND TECHNOLOGY OF PAINTS 

The substance containing water is distilled in an inert, water- 
insoluble medium, lighter than water and having a higher boiling 
point. For this purpose a mixture of toluene and xylene (1:2) is 
found most suitable. On condensing the water sef)aratQ3 quanti- 
tatively from the toluene-xylene mixture. 

150 c.c. of a dry mixture of i pure toluene (b. p. 110° to 112® C.) 
and I commercial, pure xylene are placed in a 300 c.c. Jena flask, and 
the substance to be examined added. It is well to add a small spiral 
of aluminium to produce uniform ebullition. The distillate is col- 
lected in a separatory funnel about 10 cm. in diameter, and provided 
with a glass cock having a bore of at least 5 mm. A 10 c.c. tube, 
graduated in o.i or 0.05 c.c, in which the water is collected is at- 
tached. The distillate, which is milky in appearance on account of 
suspended water, is best separated by centrifuging. The amount of 
water is then read off on the graduated tube. The toluene-xylene 
may be dried over calcium chloride and used again. 

(4) Determination of water by means of calcium 
carbide (see U. S. Circular No. 97, of the Bureau of 
Chemistry) . 

Analysis of Oils 

Specific Gravity, — This is determined at 15.5° C. 
(60° F.). For most technical purposes the hydrometer 
is universally used. Where, however, a greater degree of 
accuracy is desired or where the amount of oil available 
is rather small, the Westphal or Mohr's balance, the 
si)ecific gravity bottle, SprengeFs picnometer or finallv 
the analvtical balance mav be used. In the latter case 
the si)ecific gravity is determined by means of a plummet 
suspended from one of the balance beams and immersed 
in the oil maintained at 15.5^0. The latter is contained 
in a beaker or short cylinder placed upon a bridge so as 
not to interfere with the balance pans. 

If the i)lummct weighs in air a grams, in water w grams, and in 
the oil at 15.5° C. grams. 



ANALYSIS OF PAINT MATERIALS 335 

a — w= loss in weight of plummet when immersed in water 

= weight of vol. of water equal to vol. of plummet 
a— o = wt. of vol. of oil equal to vol. of plummet 

a — 

= sp. gr. of oil 

a — w 

For the determination of the specific gravity of 
viscous oils Lewkowitsch mentions the use of BruKl's 
picnometer. 

Eichhorn's araeopicnometer is used in the case of 
very small quantities of oil. 

In the latter case also the specific gravity of the oil 
may be obtained by preparing a mixture of alcohol and 
water so that a drop of the oil remains in suspension 
wherever it is placed in the mixture. The sp. gr. of the 
alcohol-water mixture is then determined by means of a 
hydrometer. 

It is advisable to determine the specific gravity at 
^S'S^ C. Where, however, this is not feasible a correc- 
tion^ must be made. This has been found by Allen to 
be approximately the same for most vegetable and hydro- 
carbon oils, and is equal to 0.00064 for 1° C. or 0.00035 
for 1° F. 

Saponification Value. — This expresses the number of 
mgms. of potassium hydroxid necessary to completely 
saponify the glycerides and fatty acids in i g. of oil. 

Weigh„off in a 200 c.c. Erlenmeyer flask about 2 g. of 
oil, add 25 c.c. (from a pipette) of N/2 alcoholic potash, 
and heat on the steam bath for ^ to i hour with reflux 
condenser. The contents of the flask should boil gently, 
and should be agitated occasionally. When saponification 
is complete, cool, add 5 drops of i per cent phenolphthalein 
solution, and titrate the excess of alkali with N/2 hydro- 
chloric acid solution. A blank titration is made with 

^ Allen, Comm. Org. Anal. 1910, Vol. 2, pp. 49-51. 



336 CHEMISTRY AND TECHNOLOGY OF PAINTS 

25 c.c. N/2 alcoholic potash which has been heated as 
outlined above.' The difference between the two titra- 
tions shows the number of c.c. of N/2 HCl equivalent 
to the KOH required to saponify the oil. 

The alcoholic potash must be prepared from pure grain 
alcohol (95 per cent) and chemically pure caustic potash. 
Dissolve 40 g. of the stick potash in about 25 c.c. of 
water and dilute with alcohol to i liter. After standing 
for one day the solution may be filtered from the precipi- 
tated potassium carbonate (which the stick potash always 
contains) and set aside in a uniformly cool place. 

The saponification value of an oil is valuable as a cri- 
terion of its freedom from adulteration with mineral oils. 
It does not, however, assist in detecting adulteration with 
other vegetable oils, since most of the naturally occurring 
vegetable oils have saponification values which vary be- 
tween rather narrow limits. (See table, page 343.) 

Acid Value. — This expresses the number of mgms. of 
potassium hydroxid necessary to neutralize the free 
fatty acids in i g. of oil. 

Weigh oflf s to 15 g. of oil in an Erlenmeyer flask, 
add 50 c.c. of alcohol, amyl alcohol, or ether-alcohol 
mixture (1:1), add 2 to 3 drops of phenolphthalein and 
titrate against N/io or N/5 caustic potash or soda. Of 
the above solvents amyl alcohol and ether-alcohol dis- 
solve most oils and resins almost completely. They 
are especially valuable in the case of viscous oils. Where 
alcohol alone is used it is generally best to heat it with the 
oil for a short time on the steam bath before titrating in 
order to completely extract the free fatty acids. Titrate 
cold. 

In the case of resins, and especially fossil resins, the 
method must be modified somewhat. Dissolve about i g. 
of the sample in 50 c.c. of a mixture of absolute alcohol 



ANALYSIS OF PAINT MATERIALS 337 

and benzol (i:i) or a similar mixture of alcohol and ether 
by boiling, with reflux condenser, on the steam bath. 
Titrate against N/2 or N/5 alcoholic alkali. It has been 
found in this laboratory that aqueous alkali yields acid 
values much higher than those obtained with alcoholic 
alkali. 

Oils which have been thickened by blowing generally 
have a lower acid value. On the other hand we have 
found that boiled bodied oils show a fair content of free 
fatty acids. 





Same OH Boiled 


Varnish Oil 


and Bodied 


Sp.gr. 0.933 


973 


Acid. Val. 3 . i 


14.8 


Sapon. Val. 194.2 


194.2 


Iodine Val. 193 . 2 


93-5 



Iodine Value. — This figure represents the percentage 
of iodine chloride (expressed in terms of iodine) absorbed 
by the unsaturated glycerides and acids in i g. of oil. 

Hiibl Method. — About 0.15 g. of drying oil, 0.25 g. of 
semi-drying oil or i g. of non-drying oil is weighed off in 
a capsule, placed in a 500 to 1,000 c.c. glass-stoppered 
bottle, and dissolved in 10 c.c. of chloroform or carbon 
tetrachloride. 25 c.c. of mercury iodochloride prepared 
as shown below are added from a pipette. Empty the 
pipette each time in exactly the same way, draining until 
one or two drops have fallen. Moisten the glass stop- 
per with potassium iodide solution, and set the bottle 
aside in the dark. If after two hours the color of the 
solution in the bottle is not a deep brownish red, 
add another 25 c.c. of mercury solution. When the 
reaction is complete the solution should contain an excess 
of iodine at least equal to the amount absorbed. For 
semi-drying oils allow 8 hours for complete absorption 



338 CHEMISTRY AND TECHNOLOGY OF PAINTS 

of the -iodine; for drying oils allow i8 hours. 15 c.c. 
of 10 per cent potassium iodide solution (or more in case 
a red ppt. of mercuric iodide is formed) are added, 
and the contents of the flask diluted to about 500 c.c, at 
the same time washing in any volatilized iodine trapped 
by the potassium iodide solution on the stopper. The 
excess iodine in the aqueous and chloroformic layers is 
titrated against N/io sodium thiosulphate with frequent 
agitation until the color of both layers is but faintly 
yellow. A few c.c. of freshly prepared starch solution 
are then added, and the titration continued imtil the 
blue color is discharged. A blank containing exactly 
the same quantities of solvent and mercury iodochloride 
solution must be set aside along with the oil, and then 
titrated after the addition of the same quantity of potas- 
sium iodide and water. 

The difference between the number of c.c. of sodium 
thiosulphate required to neutralize the free iodine in the 
blank and the excess iodine with the oil represents the 
amount of iodine absorbed by the oil; from the latter 
the iodine value can be calculated. 

To prepare the mercury iodochloride solution (i) 
25 g. of pure resublimed iodine are dissolved in 500 c.c. 
of pure alcohol; (2) 30 g. of mercuric chloride are dis- 
solved in the same quantity of alcohol in another bottle. 
On mixing the above two solutions and allowing to stand 
for 12 to 24 hours a solution of mercury iodochloride is 
formed containing i molecule of iodine (I2) to one mole- 
cule of HgClj. The mixed solution cannot be used for 
making iodine value determinations when it is older than 
24 hours. However, the two solutions in themselves 
will keep indefinitely. It is therefore best to prepare 
only as much iodochloride solution as is required. 

The sodium thiosulphate solution is made by dis- 



ANALYSIS OF PAINT MATERIALS 359 

solving 25 g. of the crystals in i,ocx> c.c. of water. It 
may be standardized by either of the following methods: 

(a) Against Potassium Permanganate 

Dissolve I or 2 g. of pure potassium iodide in a 400 
c.c. flask, using a small amount of water; add 5 c.c. of 
hydrochloric acid (1:1) and then 20 or 25 c.c. of an 
accurately standardized N/io potassium permanganate 
solution; the liberated iodine is titrated with the sodium 
thiosulphate solution after diluting to 200 c.c. The 
reaction involved is indicated below: 

2KMn04-f loKI-f i6HCl= i2KCl-f 2MnCl2-f SHaO-f lol. 

(b) Agaijist Potassium Dichr ornate 
KaCraOi + 6KH-14HCI = 8KC1 -f 2CrCl3 -f 7H2O -f 61 

Weigh off accurately 3.8633 g. of pure potassium 
dichromate and dissolve in exactly 1,000 c.c. of water. 
This quantity of dichromate solution is equivalent to 
exactly 10 g. of iodine liberated according to the above 
equation. In a 600 c.c. Erlenmeyer flask place 10 c.c. 
of 10 per cent potassium iodide solution and 5 c.c. of 
hydrochloric acid (1:1), and add exactly 20 c.c. of the 
dichromate solution from a burette. Dilute to 300-400 
c.c. and titrate against sodium thiosulphate after adding 
starch solution. The end point is indicated by a change 
in the color of the solution from deep blue to pale green. 

The starch solution is best prepared, as needed, by 
shaking up about 0.5 g. starch with 50 c.c. of water, 
heating, and boiling for i or 2 minutes. The solution 
should be cooled before being used. The dichromate 
solution keeps indefinitely and may be used for stand- 
ardizing the thiosulphate solution, the strength of- which 
varies slightly with age. 



340 CHEMISTRY AND TECHNOLOGY OF PAINTS 

Wijs Method. — Dissolve 13 g. of iodine in glacial 
acetic acid, and determine accurately the amount of 
iodine present, using 25 c.c. for the determination. Then 
pass dry chlorine gas into the solution until the color 
changes suddenly from deep reddish brown to pale yellow, 
due to the complete transformation of the iodine . into 
iodine chloride. The iodine equivalent of this solution 
must be exactly twice that of the original iodine solution. 
If a titration shows more than double the iodine equiva- 
lent, there is an excess of chlorine and enough iodine 
should be added to combine with it. If the analysis 
shows less than double the amount of iodine there is still 
an excess of iodine and more chlorine should be added. 

The iodine value determination is carried out exactly 
as in the case of the Hiibl method; the time of absorp- 
tion, however, is very much less, being ^ hour for non- 
drying oils, I hoiu" for semi-drying oils, and 2 to 6 hours 
for drying oils and marine animal oils. 

According to Allen, absorption in the case of oils of 
low iodine value is complete in 4 minutes, while those 
of higher value require not more than 10 minutes, provided 
too much oil is not taken. In this laboratory we have 
made it a practice to allow about i hour for semi-drying 
and drying oils. 

The values obtained by the Wijs method are as 
accurate as those obtained by the Hiibl method, and agree 
very closely with the latter. 

Bromide Test 

It has been founds that on treating the ethereal 
solutions of certain oils with a slight excess of bromine, 
an insoluble precipitate is obtained. 

^ Hehner & Mitchell, Analyst, 1898, 23, 313. 



ANALYSIS OF PAINT MATERIALS 341 

Method. — Dissolve i or 2 g. of oil in 40 c.c. of 
ether, add a few c.c. of glacial acetic acid (the precipi- 
tate formed with bromine is more granular when the acid 
is used), stopper the flask, and cool to 5° C. Add 
bromine, drop by drop, from a very fine pipette until the 
brown coloration persists. The temperature must not 
be allowed to rise. 

Allow to stand for 3 hours at 5° C, filter (preferably 
by suction); and wash four times with- ice-cold ether. 
The residue is dried in the water oven and weighed. 

The insoluble bromides obtained from linseed oil melt 
at 140 to 145° C. and contain about 56 per cent bromine. 
Those obtained from marine animal oils decompose be- 
fore melting. This property, therefore, furnishes a good 
method of detecting small amounts of the latter in 
linseed oil. 

The bromide test is useful in the examination of 
boiled and bodied oils. Lewkowitsch ' has found that 
the process of boiling linseed oil decreases the yield of 
insoluble bromides. 

On the other hand, an oil which has been bodied bv 
blowing at a low temperature will give as high a yield 
of bromides as the oil from which it is prepared. 

Lewkowitsch recommends that the mixed fatty acids, 
carefully prepared in an atmosphere of carbon dioxid 
or hydrogen, be used in making the bromide test. The 
precipitate then obtained is much easier to filter than 
when the oil is used. 

According to Eibner and Muggen thaler, ^ the bromide 
test is carried out as follows: 

2 g. of the mixed fatty acids are dissolved in 20 c.c. 
of dry ether, and cooled to minus 10° C; 0.5 c.c. 

^ Farben Ztg., 191 2, 33 ff. 

^ Muggenthaler, Inaug. Dissert., 191 2, Augsburg. 



342 CHEMISTRY AND TECHNOLOGY OF PAINTS 

of bromine are added, drop by drop, from a very fine 
pipette, allowing about 20 minutes for the addition of 
this amoimt of bromine. Another 0.5 c.c. of bromine 
are then added in 10 minutes' time. The temperature 
must not go beyond — 5® C. The flask is corked and set 
aside for 2 hours at — 10® C. The solution is then filtered 
through a weighed asbestos filter, and washed 5 times 
with dry ice cold ether, using 5 c.c. each time. 

The precipitate is then dried for 2 hours at 80 to 85® 
and cooled in a dessicator. 

Hexabromides by the above Method 

Fatty Adds from Per Cent 

PerillaOil 64.12 

Linseed Oil (Baltic) 57-96 

Linseed Oil (Dutch) 51 . 73 

Linseed Oil (La Plata) 51 .66 

Linseed Oil (Indian) 50. 50 

Tung Oil nil 

Soya Bean Oil up to .78 

Poppy Seed Oil nil 

The melting point of the bromides obtained by Eibner 
and Muggenthaler from the mixed fatty acids of linseed 
oil was 177° C. 

The following table will give an idea of the yield of 
bromides obtained from various oils: 

Material Per Cent * 

PeriUaOil 53.6 

Linseed (iodine value 181.) 23 . 14 : 23 . 52 

Linseed Oil (iodine value 186.4) 24. 17 

Linseed Oil (iodine value 190.4) 37-72 

Tung Oil nU 

Hempseed Oil 8.82 

Walnut Oil i .42 : i . 9 

Soya Bean Oil 3 . 73 

Poppy Seed Oil nil 

^ Lewkowitsch, Vol. I, p. 477. 



ANALYSIS OF FAINT MATERIALS 343 

Material Fer Cent 

Soya Bean Oil 3 . 62 

Com Oil nil 

Cottonseed Oil " 

Menhaden Oil 61.8 

Cod Oil 32.68 : 30.62 

Seal Oil 27 . 54 : 27 . 92 

Whale Oil 15.54 125 . 

Some Characteristics and Variables of Commercial Boiled Oils 



Description 



Somewhat thin and fluid. 

Very viscid 

Tacky, yielding strings. . 



Ver>' thin. 

Thin 

Thin 

Stout 

Stout 

Very stout. 
Solid 



\'ar>nng in consistence in the 
same order, from thin to very 
viscous 



Double boiled oil, I 

Commercial boiled oils, 8 samples. 



Specific 

gravity 

at is-s"" C 



0.947 
0.948 
0.961 
0.972 
0.982 
0.983 



0.9493 

0.9595 
0.9621 

0.9355- 
0.9474 



Acid 
value 



13-4 
24.9 

32.6 



8.8s 
7.06 

12.43 
19.69 

20.89 

24.97 

14.02 

4.8 

,2 

,8 

5 
,1 

7 
.8 



5 
7 
9 
9 
II, 

18. 



0.98 

3 00 

2.8-6.4 



Saponifi- 
cation 
value 



188.1-192 

• • • • • 

182.2 
180.9 

1795 

189.3 
185.6 

183.0 

193 9 
188.7 

189. 1 

189. 1 

186.6 

187 

187 
192 
191 
192 
192.8 

187.5 
192.2 



2 
2 

3 
o 

3 



Iodine 
value 



Per cent 
101.3 

77-3 

73-7 
145.1-157 



149 



7-153 



159 
100 

95 

83 

79 
76 

71 
16 



o 

7 
6 
6 
I 
2 
I 
1 .0 



2 
4 



180. 4-183. 3 



Characteristics op Boiled Oils (Lewkowitsch) 



Name 


Specific gravity 


Iodine value 


Ether-insoluble 

bromides from 

glycerides 


Linseed oil (raw) 


0.9308 
0.9429 

0.9449 
0.9310 

0.9388 
0.9483 


186.4 

171. 
169.96 

180. 1 

171. 2 
169.7 


Per cent 

24.17 

20.97 

13.03 

36.26-36.34 

25 -73 
30.19 


Pale boiled linseed oil 

Double " " " 

Ozonised " " 

(( << it 

n n tt 

# • • • • 



344 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



The Conversion of French (Metric) into English Measure 



1 cubic centimeter - 


17 mmmis. 






2 cubic centimeters - 


34 










3 


SI 










4 " - 


68 




or I dram 


8 minims. 




5 " - 


8S 




(( T « 


25 " 




6 " - 


lOI 




« . U 


41 " 




7 " - 


118 




<i - f( 


58 " 




8 " - 


ns 




" 2 drams 


IS " 




9 " - 


152 




<c 2 " 


32 " 




ID " - 


169 




« J u 


49 " 




20 " - 


338 




u ^ u 


38 " 




30 " 


507 




" I ounce 


dram 27 minims. 


40 " 


676 




« - it 


3 drams 16 




50 " 


84s 




tt - tt 


6 " S 




60 " - 


1014 




" 2 ounces 


" 54 




70 " 


1 183 




« 2 «« 


3 " 43 




80 " - 


1352 




« 2 " 


6 " 32 




90 " - 


1521 




" 3 " 


I " 21 




100 " - 


1690 




" 3 " 


4 " 10 




1000 " » 


I liter - 


34 


fluid ounces nearly, or 2^ pints. 



The Conversion of French (Metric) into English Weight 

The following table, which contains no error greater than one-tenth of a 
grain, will suffice for most practical purposes: 



I gram 


■• 


iSj grau 


2 grams 


— 


30I " 


3 




» 


46i " 


4 




« 


6ii " 


5 




a 


77i " 


6 




« 


92! " 


7 




s 


108 


8 




» 


123? " 


9 




» 


154* " 


10 




» 


II 




a 


i69t " 
185* " 


12 




a 


13 




a 


200i " 


14 




=. 


216 


15 




= 


231} " 


16 




a 


247 ** 


17 




a 


202^ " 


18 




a 


277^ " 


19 




1^^ 


293i " 


20 




» 


308? " 


30 




» 


4^>3 " 


40 




a 


6i7^T " 


50 




= 


//If 


(K> 




a 


026 


70 




B 


loSol " 


80 




«. 


1234! " 


90 




- 


1389 " 


100 




-0 


1543^ " 


1000 




- 


1 kilogram 



32 "Z-, I 



or I dram li grain. 
17JI grains. 
325 



I 
I 
I 



2 drams 

2 

2 

2 

3 
3 
3 
3 

4 
4 
4 
4 

^ 

:> 

7 
10 
12 

15 
18 

20 
23 

25 
dr., 125 gr. 



48 

3? 
i8t 

34! 

49J 

5i 

205 
36 

7 

S3i 
8?. 
43 
I7i 

si; 

26 
o\ 

345 

9 
43I 



14 

u 
u 
It 
tt 
tt 
tt 
tt 
tt 
tt 
tt 
It 
tt 
It 
tt 
tt 
tt 
tt 
tt 
tt 
tt 
it 
tt 



ANALYSIS OF PAINT MATERIALS 



345 



Metric System of Weights and Measures 
Measures of Length 



Denominations and Values 


Equivalents in Use 


Mvriameter 


10,000 meters. 
1 ,000 meters. 
100 meters. 
10 meters. 
I meter, 
i-ioth of a meter, 
i-iooth of a meter, 
i-ioooth of a meter. 


6.2117 miles. 


K.ilometer 


328 

393 

39 

3 


62137 mile, or 3.280 ft. 10 ins. 


Hectometer 

Dekameter 

Meter 

Decimeter 

Centimeter 

Millimeter 


feet and i inch. 
7 inches. 
37 inches. 
937 inches. 
3937 inch. 
0394 inch. 



Measures of Surface 



Denominations and Values 


Elquivalents in Use 


Hectare 

Are 

Centare 


10,000 square meters. 
100 square meters. 
I square meter. 


2.471 acres. 
119.6 square yards. 
1,550. square mches. 



Measures of Volume 



Denominations and Values 


Equivalents in Use 


Names 


No. of 
Liters 


Cubic Measures 


Dry Measure 


Wine Measure 


Kiloliter or stere. 

Hectoliter 

Dekaliter 

Liter 


1,000 

100 

10 

I 

I-IO 

l-IOO 

I-IOOO 


I cubic meter, 
z-ioth cubic meter. 
10 cubic decimeters. 
I cubic decimeter, 
i-ioth cubic decimeter. 
10 cubic centimeters. 
I cubic centimeter. 


1 . 308 cubic yards. 

2 bu. and 3.35 pecks. 

9.08 quarts. 

. 908 quart. 
6. 1023 cubic inches. 

.6102 cubic inch. 

.061 cubic inch. 


264.17 gallons. 
26.417 gallons. 
2.6417 gallons. 
1.0^67 Quarts. 


Deciliter 

Centiliter 

Milliliter 


.845 Rill. 
.338 fluid oz. 
.27 fl. drm. 



Weights 



Denominations and Values 


Equivalents 
in Use 


Names 


Number of 
Grams 


Weight of Volume of Water 
at its Maximum Density 


Avoirdupob 
Weight 


Millier or Tonneau 


1,000,000 

100.000 

10,000 

1,000 

100 

10 

I 

l-IO 

I-IOO 

I-IOOO 


I cubic meter. 

I hectoliter. 
10 liters. 

I liter. 

I deciliter. 
10 cubic centimeters. 

I cubic centimeter. 

z-ioth of a cubic centimeter. 

10 cubic millimeters. 

I cubic millimeter. 


2204.6 pounds. 
220.46 iwunds. 
22.046 pounds. 
2 . 2046 pounds. 
3.5274 ounces. 
.3527 ounce. 
15 432 grains. 
I ■ 5432 grains. 
.1543 grain. 
.0154 grain. 


Quintal 


Mviiasram 


Kilosrram or Kilo 


Hectosram 


Dekaeram 


Gram 


Decieram 


Centiirram 


Milligram 





For measuring surfaces, the square dekameter is used under the term of ARE: the hectare, or 100 
ares, is equal to about 2^ acres. The unit of canity is the cubic decimeter or LITER, and the series 
of measures is formed in the same way as in the case of the table of lengths. The cubic meter is the 
unit of measure for solid bodies, and b termed STERE. The unit of weight is the GR.XM, which is 
the weight of one cubic centimeter of pure water weighed in a vacuum at the temperature of 4 deg. 
Cent, or 39.2 deg. Fahr.. which is about its temperature of maximum density. In practice, the term 
cubic centimeter, abbreviated c.c, is generally used instead of milliliter, and cubic meter instead of 
kiloliter. 



546 



CHEMISTRY AND TECHNOLOGY OP PAINTS 
Specific Gravity of Various Materials 



Acetic Add 

Acetone 

Acetylene 

Acrylic Add 

Agate 

Alabaster 

Aluminium Oxid 

" Sulphate 

" i8H,0. 
Alum, Potassium 

" Soda 

" Ammon. Chrome. . 

" Potass. Chrome. . . 

Amber 

Ammonia (gas) 

(liq.) 

Ammonium Carbonate 

NHiHCQ,.. 

Chloride . 

" Nitrate 

" Sulphate 

" add 

Amyl Acetate 

" Alcohol 

" Valerianate 

Aniline 

Anthracene 

Anthracite 

Antimony Oxid, Tri 

" Tetra . . 
" " Penta.. 

" Pentasulphide. 

Arsenic Disulphidc 

" Pentoxid 

•* Trioxid 

Asbestos 

Asphalt 



<< 



1.0607 V 

.788-.790 

.92 

1.063 1 y 

2.5-2.8 

2.3-2.8 

3-75-3.99 

2.71 
1.62 

I.7S 
1.65 

1.81278 (o.'O 

I.O-I.I 

•5971 
.6234 (o. ) 

1.586 

1.520 (i7.p 
1.725 (15. ) 
1.7687 V 

1.787 
.8792 (20. J 

.8144-8430 

.8812 (o.^) 

1.0276 (12.**) 

1.147 
M-1.7 

5.2-5.7 
4.07 

3.78 ^ 
4.120 (o. ) 

3-4-3.6 
3.99-4.25 

3.646 

1.2 
I.I-I.5 



(t 



tt 



it 



ti 



Barium Carbonate 4.27-4.37 

Chloride 2H2O. .3.097 V 

I*croxid 4958 

Sulphide 4.25 

Sulphate 4.33-4.476 

Barley 51-69 

Baryles 4-476 

Basalt 2.7-3.2 

Bees Wax (see wax). 
Beef suet m.p. 3i.°-3i.5° 

C 968 

Bellmetal 8.81 

Benzene b. p. 80.5"^ C 8799(2o.°C.) 

Benzoic Acid 1.201 (21.°) 

Blanr Fi.xc 4.02-4.53 

Blue Vitriol 2.27 

Bones 1.7-2.0 

Borie Acid 1.46 

Butter 865-868 

Butyric Acid 9599 ^ 



« 

({ 
« 
« 
« 
« 
« 
« 



admium Sulphide (artif.). . . 3.9-4.8 C 
" " (Greenockitc).4.&-4.9 

Caldum Carbide 2.22 

Carbonate 2.72-2.95 

Chloride (6 HtO) 1.654 

" 2.26 

Fluoride 3.15-3.18 

Hydroxid 2.078 

Oxid 3.i5-3«40 

Sulphate 2.964 

(Gypsum) 2.32 

Sulphide 2.8 

Tungstate 6.062 

Camphor 992 

Caoutchouc 92-.96 

Carbolic Add 1.0597 (33.**) 

Carbon (Amorphous). . . .z. 75-2. 10 

" (Graphite) 2.10-2.585 

" (Diamond) 3.47-3.5585 

" Dioxid 1.529 

** Disulphide 1.28 

'' Monoxid 0.967 

" Tetrachloride 1.59 

Cast Iron 7.25 

Cellulose 1.27-1.45 

Charcoal (Airfilled) 0.4 

" (Airfree) 1.4-1.5 

Chlorine 2.491 

Chloiofonn 1.5264 

Chrome Alum Crt(S04)s. 

KtS04. 24H,0 1.81278 

Chromic Oxid 5.04 

Chromium 6.92 

Chromium Trioxid 2.67-2.82 

Citric Add 1.542 

Clay 3.85 

Cobalt Chloride 2.94 

Cobaltic Oxid (CoA) • • .4.81-5.6 
Cocoabutter (m.p. 33.5°- 

34.° Q 89-.91 

Copal 1.04-1.14 

Copper 8.91-8.96 

Copper Carbonate, Basic. 3. 7-4.0 

Cork 24 

Corundum 4.0 

Cotton (Airdr>') 1.4 7-1. 5 

Cr>'olite AlFs3NaF 2.9 

Cupric Hydroxid Z-S^ 

Oxid (Black) 6.32-^.43 

Sulphate 3.516 

Sulphate (5HsO).. 2.284 

Sulphide 3.8-4.16 

Cuprous Oxid (Red) 5.75-<>.oq 

C>'mene b. p. 175.°-! 76.® 0.862 (20.**) 

Dextrin 1*0384 

Diamond 3.49-3.52 

Dolomite 2.9 



II 



u 



u 



tt 



ANALYSIS OF PAINT MATEIRALS 



347 



Specific Gkavity of Various Materials — Continued 



Earth: 

Gravel, dry 1.4 

Humus 1.3-1.8 

Lean 1.34 

Loam 1.6-1.9 

Ethane 1.036 

Ether (Diethyl) 0.7183 (17.°) 

Ethyl Acetate 8920-.9028 

Ethyl Alcohol 7937 y 

Ethylene 9784 

Eucal>'ptol 9267 (20.°) 

Eugenol 0630 (i8.°) 



t< 



« 



(( 



n 



Ferric Chloride 2.804- (10.8 ) 

Hydroxid 3.4"~3.9 

Oxid 5.12-5.24 

Ferrous Carbonate 3.70-3.87 

Sulphate 1.86-1.90 

Sulphide 4.75-5.04 

Flax (airdry) - 1.5 

Fish Oil 0.920-0.928 

Formaldehyde (-20.°) 8153 

Formic Acui 1.219-25° 

1.244—0 

Fumaric Acid 1.625 

Furfural i.i594 -V 

Gasoline (b. p. 70^.-90.°) . .66-.69 

Gas Carbon i . 88 

Glass: 

Window 2.4-2.6 

Mirror 2.45-2.72 

Crystal 2.95 

Flint 3-0-5-9 

Glue 1.27 

Gneiss 2.4-2.7 

Granite 2.51-3.05 

Graphite (Natural) 2.17-2.32 

" (Artificial) 2.10-2.25 

Gum Arabic 1.31-1.45 

Guttapercha 981 

Gypsum 2.32 

Hemp (Air-dry) 1.5 

Hornblende 3.0 

Hydriodic Acid 4.3737A 

Hydrobromic Acid 1.278A 

Hydrochloric Acid 1.195 (8°) 

Hydrocyanic Acid .697 (i8.°) 

Hydrofluoric Acid 9879 (15.°) 

Hydrogen 06949 

Hydrogen-peroxid 1.4584 (0.°) 

Hydrogen-sulphide 9-1. 1895 

Hydroquinone 1.326 

India Rubber 93 

Indigo 1.35 

Iodic Acid 4.629 (0.°) 



Iodine 4.948 (17.°) 

Iodoform' 4.09 

Iron (pure) 7.85-7.88 

" (gray pig) 7.03-7.13 

" (white pig) 7.58-7.73 

" (cast) 7.217 

" (wrought) 7.86 

" Bisulphide 4.86-5.18 

" Sesquioxid 5.12 

Ivory 1.82-1.92 

Japan ^Wax (m. p. 53.5°- 
54.5°) 992 

Kaolin 2.2 

Lactic Acid 1.2485 

Lard (m. p. 41.5-42.C.). . .92-.94 

Lava 2.00-3.00 

Lead (milled sheet) 11.42 

" (wire) 11.28 

Acetate. 3H2O 2.50 

Carbonate 6.43 

** , Basic. . .6.323-6.492 

" Chloride 5.8 

Chromate 6.123 (15.*^) 

Hydroxid 

(3PbOH20) 7.592 

** Iodide 6.12 

" Nitrate 4.5 

" Oxid (PbO) 9.2^.5 

" (PbaOO 9.096(15.°)° 

Sulphate 6.23 

Sulphocyanate 3.82 

Tungstate 8 235 

Leather 86-1.02 

Lime (unslacked) 1.3-1.4 

" (slacked) 2.3-3.2 

Limestone 1.86-2.84 

Linolemn 1.15-1.3 

Linseed Oil (raw) 93 -.934 

" " (boiled) 934-.940 

Litharge (natural) 7.83-7.98 

" (artificial) 9.3-9.4 

Lithimn Carbonate 2.1 1 1 

Chloride 1.998-2.074 



II 



ii 



It 



II 



u 



u • 
tt 
it 
It 



<( 



Malachite. 3.85 

Manganese Chloride 

(MnCl^HjO) 1.913 

Manganese Nitrate 1,82 

Oxid (M nO) . . 5 .09-5 . 1 8 
" (Mn02)5.026 
" (Mn2Q8)4.325-4.82 
Sulphate 
(MnS047H20). 2.092 
Marble : 

African 2.8 

British 2.71 



n 



<< 



a 



n 



348 



CHEMISTRY AND TECHNOLOGY OF FAINTS 



Specific Gra\ity of Various Materials — Continued 






Marble: 

Carrara 2.72 

Egyptian, Green 2.67 

Florentine 2.52 

French 2.65 

Marl 1.6-2.5 

Masonry : 

Ashlar Granite 2.37 

Limestone 2.32-2.70 

Millstone 2.01-2.51 

Sandstone 2.61 

Rubble (dr>') 2.21 

" (mortar) 2.42 

Meerschaum 99-1.28 

Mercuric Chloride 5.32-5.46 

" Oxid 11.0-11.29 

Mercuric Sulphide: 

(HgS black) 7-55-7. 70 

(HgSred)..... 8.06-8.12 

Mercurous Chloride: 

(Calomel) 6.482-7.18 

Methyl /Ucohol 7984 (15.°) 

Methyl Ethyl Ether 7252 (0.°) 

Mica 2.65-3.2 

Milk (cow's) 1. 028-1. 035 

Milk Sugar 1.525 (20. ) 

Molybdic Acid: 

HjMoOiH^O 3.124 (15°) 

Morphine 1.317-1.326 

Mortar (hardened) 1.65 

Mutton Suet (m.p.47.® C.) .92 

Napthalene 1.1517 

(15.° C.) 

Na])hthol a 1.224 (4.° C.) 

fi. 1. 217(4.° C.) 

Xcatsfoot Oil 914 (39.°F.) 

Nickel (rolled) 8.67 

'^ (cast) 8.28 

Nicotine i.oii 

Nitranilinc m 1.43 

P 1.4-24 



V 



Oats 43 

Ochrc 3.50 

Oleic Acid 8qoS 

(12.° C.) 

Oolitic Stones 1.89-2.6 

Opal 



Oxalic .\ci(l 1.^)53 (i8.°C.) 

Oz)ne 1.058 (.\.) 

Palmitic Acid 846^ 

(7.6" C.) 
Palm Oil (m. p. 30.°C.). . . .905 

PajHT 70- 1. 15 

ParalVine: 

m. p. 38.-52.°C 87-.88 



m. p. 52.-50. 



'C 



.S8-.93 



Pearls 2.72 

Peat 1. 2-1. 5 

Petroleum Ether: 

b. p. 40.-7o."C 65-.66 

Phenol 1.0597 isS'^'C.) 

Phosphorus (yellow) 1.8232 

(red) 2.11 

Phthalic Acid i. 585-1. 593 

** anhydride... 1.527 (4.'*^C.) 

Picric Acid 1.813 

Pinene 8587 

(20.° C.) 

Pitch 1.07-1.10 

Plaster of Paris : 2.96 

Platinum 21.52 

Porcelain: 

Berlin. •. 2.29 

Meissen 2.49 

Sevres 2.24 

China 2.38 

Portland Cement i. 25-1. 51 

Potash 2.10 

Potassium 875 ( 13°) 

Bromide 2.756 -j* 

Carbonate. ... 2.29 

" (2H20)2.o43 

Chlorate 2344 ( 1 7°) 

Chloride i .994 y 

Chromate. . . . 2.721 (4°) 

Cyanide 1.52 (16°) 

Bichromate. . .2.692 (4°) 
P'crricyanide. .1.8109 07°) 
Fcrn)cyanide . 1.8533 07^) 

Hydro.xid 2.044 

Iodide 3.043 1^24.3^) 

Nitrate 2.1 (4.^) 

Permanganate 2.70 

Sulphate .?-6633 y 

*' . Acid 2.245 
Sulphide KjS. 2.13 
Sulphocyanate i .006 

Tartrate 1-975 

Potatoes 1. 10 

Pumice nat.) v~0O 

(artif.j 2.2-2.5 

Pyridin g855 (15.') 

Pyrogallol i.4^>3 (40.'; 

Realgar AsjSa 3.4-3-6 

Red Lead 9.07 

Rosin 1.07 

Ruby 3.95-4.02 

Salt (table) 2. 15- 2.1 7 

Sand (dry) 1.4- 1.05 

'' (moist) 1.9-2.05 

Sandstone 2.2-2.5 



It 
<< 
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(t 
(< 
II 

u 
II 
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It 

n 

ii 
i( 
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i( 

(< 

ii 
ii 



A^'ALVSIS OF PAINT MATERIALS 



349 



Specific Gravity of Various Materials — Continued 



<( 



(< 



n 



it 



Sapphire 3.95-4.02 

Serpentine 2.4-2.7 

Silicon (cryst.) 2.49 (io.°) 

(graphitic) 2.0-2.5 

(amorphous) 2.00 

Silk (raw) 1.56 

Silver Chloride 5-56i 

Cyanide 3.95 ^ 

Nitrate 4.352 (19. ) 

Slate 2.65-2.7 

Snow (loose) 1 25 

Sodium Acetate 1.4 

Bicarbonate 2.19-2.22 

Bromide 2.95-3.08 

Carbonate 

(anhyd.) 2.43-2.51. 

Carbonate 

10 H2O 1.446 (17-) 

Chloride 2.1741 (V) 

Chromate 2.71 (16. ) 

Dichromate 2.52 (i6.°) 

Hydroxid 2.13 

Nitrate 2.267 V* 

Nitrite 2.157*^ 

Oxid 2.805 

Peroxid 2.805 

Phosphate 

Na2HP04i2H,0 1.5235 (16.**) 
Potassium Tar- 
trate 1.77 

Sulphate (anhyd.) 2.67 1 V 

10H2O.. 1.492 (20.**) 
Sulphide NajS. . . 2.471 
Sulphite 7H2O. . . 1 . 561 

acid 1.48 

Tartrate i-794 

Tetraborate 

(Borax) 1.694."® 

Thiosulphate 

5H2O 1.729 (17.°) 

Tungstate 3.259 (17.5°) 

Spathic Iron Ore 3-7-3-9 

Stannous Chloride 2H2O. . 2.71 (15.5°) 

Starch i. 53-1. 56 

Stearic Acid 8428 ^ 

Stearin 9245 (65.®) 

Steel 7.6-7.8 

Strontium Chlorate 3.152 

Strontium Nitrate 2.24-2.98 



ti 



It 



n 



ti 



n 



it 



<< 



it 



a 



a 



a 



a 



a 



it 



a 



<t 



(( 



a 



a 



a 



ti 



a 



a 



a 



ti 



it 



Sugar (cane) 1.588 (20.) ^ 

Sulphur nat 2.07 

amorph. soft 1.9556 (0.°) 

plastic S7 1.92 

monoclinic S/3 . . .1.958 

rhombic So 2.05-2.07 (0°) 

Sulphur Dioxid 2.2639 

Sulphuric Acid H2SO4. . . . 1.8342 V 
Syenite 2.6-2.8 

Talc 2.7 

Tartaric Acid i. 666-1. 764 

Terpincol 9357 (20.°) 

Thymol (3:2:1) 0941 (0.°) 

Titanium Oxid Ti02 3.75-4.-5 

Toluene 866 y 

Toluidine 998-1.046 

Tungsten Oxid WO2: 

(brown) 12. 11 

Tungsten Oxid WO3: 

(yellow) 7.16 

Urea i .323 

Uric Acid. i . 855-1 . 893 

Verdigris 1.9 

Wax, Bees: 
Yellow m.p. 62.-62.5. "C .96-.965 
White ni. p. 63.-63. 5®C. .96-.Q69 

Wax, Japan: 

(m. p. 53-S°-54-5°) • • -992 

WTieat 7-.8 

Wood (see table on page 351). 
Wool (sheep) air-dry 1.32 



Xvlene o 8032 (c.°) 

m. 866 V 

p 8801 (0.°) 



ti 



ti 



Zinc Acetate i . 84 

Blende ZnS 4.03-4.07 

Carbonate 4.42-4.45 

Chloride 2.91 V 

(JXIQ 5.7^ 

Sulphate anhvd 3.6235 (15.°) 

7H2O 1.964 

Sulphide 3.98 



it 
ti 
it 
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a 



(All temperatures, unless otherwise noted, are given in Centigrade degrees.) 



350 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



Si»EciFic Gravity of the Elements 



Aluminium 2.66 

Antimony 6.62 

Argon 1.379 (Air-I) 

Arsenic 5.73 

Barium 3.75 

Bismuth 9.80 

Boron 2.50 

Bromine 3.15 (Air-I) 

Cadmium 8.64 

Caesium 1.88 

Calcium 8.64 

Carbon.... I'H 

3-53 
Cerium 6.68 

Chlorine ^.49 (Air-I) 

Chromium 6.50 

Cobalt 8.60 

Columbium (Niobium). 7.20 

Copper 8.933 

Erbium 4.77 

Fluorine 1.26 (Air-I) 

Gadolinium 1.31 

Gallium 5.95 

Germanium 5*469 

Glucinum (Beryllium).. 1.93 

Gold 19.32 

Helium 1 363 (Air-I) 

Hydrogen o6g6 (Aii^I) 

Indium 7.12 

Iodine 4-943 

Iridium 22.42 

Iron 7-86 

Krypton 2.818 (Air-I) 

lanthanum 6.1545 

Lead 11.37 

Lithium 59 

Magnesium 1.74 

Manganese 7-39 

Mcrcur>' 13-55 

Molybdenum 8.60 

Neodymium 6.956 

Xeon 674 (.Vir-I) 

Nickel 8.90 



Nitrogen 96737 

Osmium. 22^8 

Oxygen.- 1.10535 (Air-I) 

Palladium 11.40 

Phosphorus: 

(White) 1.83 

(Red) 2.20 

Platinum 21.50 

Potassiimi 87 

Praseodymium 6.4754 

Radium 

Rhodium 12.10 

Rubidium 1.52 

Ruthenium 12.26 

Samarium 7.7-7.8 

Scandium 

Selenium 4.8 

Silicon: 

(Cryst.).' 2.39 

(Graphitic) 2.00 

(Amorph.) 2.35 

Sflver 10.50 

Sodium 978 

Strontium 2.54 

Sulphur 2.07 

Tantalum 10.4 

Tellurium 6.25 

Terbium 

Thallium 11.85 

Thorium 1 i.oo 

Thulium 

Tin 7.29 

Titanium 3.543 

Tungsten: 

(Wolframium) 19. i 

Uranium 18.7 

Vanadium 5.50 

Xenon 4.422 (.\ir-I) 

Ytterbium 

Yttrium 3.80 

Zinc 7.25 

Zirconium 4.15 



Pounds of Oil Required for Grinding 100 Pounds Various Dry Ph;ments 

INTO Average Pastes* 



Asbestine 32 

Barytcs (Xat.) 9 

Black, Ik>ne 50 

Black. Drop 50 

Black, Hydro Gas Carl>on 88 

Black. Lamp 78 

Blanc Fixe 25 

Blue, Chinese or Prussian 62 



Blue, Ultramarine 28 

Brown, Mineral 24 

BrowTi, Vandyke 58 

China Clay 2S 

Dutch Pink (Quercitron I^kc) 2S 

(Jraphite (Plumbago), qo*'( 48 

Clrecn, Pure, Light, Chrome 21 

Green, Pure, Dark, Chrome 2S 



ANALYSIS OF FAINT MATERIALS 



351 



Green, 25% Color, Light Chrome. 18 

Green, 25% Color, Dark Chrome. 20 

Green Earth (Terhi Verte) 32 

Green, American, Paris 23 

Green, English Paris 20 

Green, Ultramarine '.'... 28 

Gypsum 22 

Lithopone 30-25 

Ochre (American) 28 

Ochre (French) 28 

Ochre, Golden (Pure) ' 30 

Red, Indian (Pure q8%) 20 

Red, Tuscan 2q 

Red, Venetian 23 

Red Iron Oxid, Pure 28 

Red Lead. . . ! 10 

Sienna, Raw American 45 

Sienna, Burnt Italian 45 



Sienna, Raw Italian 52 

Silex 24 

Umber, Burnt American 36 

Umber, Raw American 38 

Umber, Burnt Turkey 47 

Umber, Raw Turkey 48 

Vermilion, American (Chrome Red) 18 

Vermilion, English (Mercury) 14 

White Lead (Basic Carbonate) 10 

White Lead (Basic Sulphate) 11 

White, Paris (Whiting) 20 

Yellow, Lemon, Chrome 28 

Yellow, Med., Chrome 30 

Yellow, Orange, Chrome 20 

Yellow, Dk. Orange, Chrome 18 

Zinc Lead 12 

Zinc Oxid (American), ordinary , . 18 

Zinc Oxid (White Seal) 20 



* These figures are approximately correct. For instance, lamp black is 
given as 78 pounds. There are, however, some lampblacks which require as much 
as 100 pounds, and others which require as low as 70 pounds, but 78 pounds is the 
exact amount for commercially pure lampblack. This figure means that 100 
pounds of lampblack will require 78 pounds (about 10 gallons) of oil to make 
a stiff paste. 



Specific Gravity of Various Woods 



Acacia 

Alder 

Apple 

Ash 

Birch 

Box 

Cedar 

Cherry 

Ebony 

Ebn 

Fir 

Mahogany. . . 

Maple 

Mountain Ash 

Oak 

Pear 

Pine 

Plum 

Poplar 

Willow 



Air dry 



58- -85 

42- .68 

C6- .84 

57- -94 

51- -77 
91-1 . 16 

57 .-. 

76- .84 

26 ... 

56- .82 

37- .75 
56-1.06 

53- .81 

69- .89 

69-1.03 

61- .73 

35- .60 

68- .90 

39- -59 

49- -59 



Fresh 



75-1 00 
63-1. 01 

95-1 • 26 
70-1.04 
80-1 .09 
20-1 . 26 



05-1. 18 



78-1 . 18 
77-1-23 



83-1.05 
87-1 13 

93-1 • 28 
96-1 .07 
40-1 . 07 

87-1. 17 
61-1 .07 

79 ••• 



352 



CHEMISTRY AND TECHNOLOGY OF PAINTS 



Table Showing the Comparison of the Readings of Thermometers 



Celsius, or Centigrade (C). R6aumur (R). Fahrenheit (F). 



C 


R 


-30 


— 24.0 


- 25 


- 20.0 


- 20 


— 16.0 


- 15 


- 12.0 


- 10 


- 8.0 


- 5 


- 40 


- 4 


- 32 


- 3 


- 2.4 


- 2 


- 1.6 


— I 


- 0.8 



+ 



22.0 

13.0 
4.0 
50 

14.0 
23.0 
24.8 
26.6 
28.4 
30.2 



Freezing point of water. 



o 
I 
2 

3 

4 

5 
6 

7 
8 

9 

10 

II 
12 

13 

14 

15 
16 

17 
iS 

10 
20 
21 



0.0 
0.8 
1.6 
2.4 
32 
4.0 
4.8 
5-6 

6.4 

7.2 

8.0 

8.8 

9.6 

10.4 

II . 2 

12.0 

12. ii 

13.0 

14 4 

15 2 
16.0 
16,8 
17. ^> 



32.0 

33-8 
35-6 

37-4 
39 2 
41.0 
42.8 
44.6 
46.4 
48.2 
50.0 
51.8 
53 6 

55 4 
57 2 
59 o 
60.8 
62.6 
64.4 
66 . 2 
68 . o 
6g.8 
71.6 



23 

24 

25 
26 

27 
28 

29 
30 
31 
32 
33 
34 
35 
36 
37 
38 

39 
40 

41 
42 

43 

44 

45 

50 

55 
60 

65 
70 

•• ^ 

80 
85 

95 
100 



R 



18.4 
19.2 
20.0 
20.8 
21.6 
22.4 
23.2 
24.0 
24.8 
25.6 
26.4 
27.2 
28.0 
28.8 
29.6 

304 
31 2 
32.0 
32.8 

33 6 

34 4 

35 2 
36.0 
40.0 
44 o 
48.0 
52.0 
56.0 

(^K3.0 
64.0 
68.0 
72.0 

76 o 

80.0 



73 4 

75 2 

77 o 

78.8 

80.6 

82.4 

84 2 

86.0 

87.8 

89.6 

91.4 

93 2 

95 o 

96.8 

98.6 

100.4 

102.2 

104.0 

105.8 

107.6 

109 

III 

113 
122 

131 
140 

I4Q 

i5'S 
167 
176 

i«S5 
194 

203 
212 



4 
2 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 



Hoilinjj ix)int of water. 



Readings on one scale can be changed into another by the following formuhe, 
in whidi r indicates degrees of temperature: 



Reau. to Tahr. 
V R i s^^' = l^ I' 



Reau. to Cent. 



V R -. /' C 



Cent, to Fahr. 

^/" C + 32" = f I' 
5 

Cent, to Reau. 

\r C = /" R 

5 



Fahr. to Cent. 
Fahr. to Reau. 



ANALYSIS OF PAINT MATERIALS 



353 



International Atomic Weights. 19 13 



0-16 

Aluminium Al 27-1 

Antimony Sb 120-2 

Argon A 39 • 88 

Arsenic As 74*96 

Barium Ba i37*37 

Bismuth Bi 208-0 

Boron B 11 -o 

Bromine Br 79-92 

Cadmium Cd 112-40 

Careium Cs 132-81 

Calcium Ca 40-07 

Carbon C 12-00 

Ceriimi Ce 140-25 

Chlorine. CI 35*46 

Chromium Cr 52-0 

Cobalt Co 58^7 

Columbium Cb 93-5 

Copper Cu 63-57 

Dysprosium Dy 162-5 

Erbium Er 167-7 

Europium Eu 152-0 

Fluorine F 19-0 

Gadolinium Gd 157-3 

Gallium Ga 69-9 

Germanium Ge 72-5 

Glucinum Gl 9-1 

Gold Au 197 • 2 

Helium He 3-99 

Holmiimi Ho 163 - 5 

Hydrogen H i -ooS 

Indium In 114-8 

Iodine I 1 26 • 92 

Iridium Ir 193 - 1 

Iron Fe 55*84 

Krypton Kr 8292 

Lanthanum La 139-0 

Lead Pb 207-10 

Lithium Li 6-94 

Lutecium Lu 1740 

Magnesium Mg 24-32 

Manganese Mn 54-93 

Mercury Hg 200-6 



o = 16 

Molybdenum Mo 96-0 

Neodymium Nd 144-3 

Neon Ne 20-2 

Nickel Ni 58-68 

Niton(radium emanation). Nt 222-4 

Nitrogen N 14-01 

Osmium Os 190-9 

Oxygen O 16.00 

PaUadium. Pd 106 - 7 

Phosphorus P 31 -04 

Platinum Pt 195 - 2 

Potassium K 39 * 10 

Praseodymium Pr 140-6 

Radium Ra 226-4 

Rhodium Rh 102-9 

Rubidium Rb 85-45 

Ruthenium Ru loi - 7 

Samarium Sa 150-4 

Scandium Sc 44-1 

Selenium Se 79-2 

Silicon Si 28-3 

Silver Ag 107-88 

Sodium Na 23-00 

Strontium. Sr 87-63 

Sulphur S 32-07 

Tantalum Ta 181 -5 

Tellurium Te 127-5 

Terbium Tb 159-2 

Thallium Tl 204-0 

Thorium. Th 232-4 

Thulium Tm 168-5 

Tin Sn 119-0 

TiUnium Ti 48-1 

Tungsten W 184-0 

Uranium. U 238-5 

Vanadium V 51-0 

Xenon Xe 130 • 2 

Ytterbium(Neoytterbium)Yb 172-0 

Yttrium Yt 89-0 

Zinc Zn 65-37 

Zirconium Zr 90-6 



PHOTOMICROGRAPHS 



I. 
2. 

3. 
4. 

6. 

7. 

8. 
9. 



NUMBER PAGE 

Corroded WTiite Lead. 29 

Old Process A\Tiite Lead. 30 

White Lead (New Process). 31 

Sublimed White Lead. 36 

Standard Zinc Lead White. 38 

Ozark White. 40 

American Zinc Oxid. 43 

French Green Seal Oxid. 44 

Lithopone (dry). 47 

10. Lithopone (ground in oil). 48 

11. Litharge. 54 

12. Litharge. 55 

13. French Orange Mineral. 57 

14. Red Lead (Photomicrograph 

of paint film freshly ap- 
plied, showing separation of 

the pigment from the oil). 58 

15. Red Lead (Photomicrograph 

of red lead applied one hour 
after mixing, showing sepa- 
ration and air bells en- 
cysted in film). 59 
English Venetian Red. 64 
American Venetian Red. 65 
American Hematite. 66 
Indian Red. 66 
American Burnt Sierma. 72 
Prince's Metallic. 75 
Ordinary American Washed 

Ochre. 79 

American Washed Ochre. 80 

J. F. L. S. Ochre. 81 

Ultramarine Blue. 85 

26. Ultramarine Blue (ground in 

oil). 8s 

27. Artificial Cobalt Blue. 88 

28. Lampblack. 99 



16. 

17. 
18. 

19. 

20. 

21. 

22. 



23- 

24. 

25. 



NUMBER 

29. Carbon Black. 

30. Natural Graphite. 

31. Natural Graphite. 

32. Artificial Graphite. 

33. Artificial Graphite. 

34. Fine Charcoal. 

35. Charcoal Black. 

36. Vine Black. 

37. Wood Pulp Black. 

38. Drop Black. 

39. Drop Black. 

40. Barytes. 

41. Bar>'tes, /\merican. 

42. Blanc Fixe. 

43. Blanc Fixe. 

44. Barium Carbonate. 

45. Silica or Silex. 

46. Silica. 

47. Silica. 

48. Infusorial Earth. 

49. Diatoms. 

50. Diatoms. 

51. Clay. 

52. China Clay. 

53. Colloidal Clay. 

54. Asbestine. 

55. WTiiting. 

56. Gilder's A\Tiiting. 

57. Calciimi Carbonate, artificial. 

58. Talc (Soapstonc). 

59. Basic Magnesium Carbonate. 

60. Alumina Hydrate. 

61. American Gypsum. 

62. American Gypsum. 

63. American Terra Alba. 

64. Calcium Sulphate (Gypsum). 

65. P>cnch Terra Alba. 



PACE 
100 
lOI 

102 

103 

104 

105 

los 
106 
107 
108 
108 

113 

115 
117 

120 

122 

123 

123 

124 

126 

127 

127 

128 

129 

129 

130 

131 

131 
132 

132 

133 
^33 
136 
136 
136 
136 

137 



356 



PHOTOMICROGRAPHS 



NUMBER PAGE 

66. Terra Alba (French Gypsum). 137 

67. Calcium Sulphate. 137 

68. Precipitated Calcium Sul- 

phate. 137 

69. Photomicrograph of Portland 

cement floor composed of 2 
parts sand and i [>art 
cement. 147 

70. Highly magnified view of a 



NUMBER PAGE 

fine crack in Portland 

cement construction. 148 

71. Olive green fungus growing 

on paint. 284 

72. Penicilium Crustaceum. 285 

73. Aspergillus Niger. 2S5 

74. Aspergillus Niger. 286 

75. Aspergillus Flavus. 286 

76. Cladosphorium Herbarum. 287 



INDEX 



Acetylene black, as black toner,- io8 
Acid value, det. in oils and resins, 336 
Adulteration of white lead, 16, 17 
Alabaster, use in making g>'psum, 137 
Alum salts, use in fireproofing wood, 

129 
Anti-fouling paints, preparation of, 144, 

145 
Antwerp blue — see Prussian blue 

Asbestine, analysis of, 130, 312 

composition, 128 

fireproof paint, use in, 1 28 

shingle stain, use in, 156 
Asbestos, fireproof paints, use in, 128 

identification, 130 
Aspergillus Flavus, 286 
Aspergillus Niger, 286 
Asphalts, influence of sunlight on, 261, 
262 

chemical composition of, 262 

Bancroft — see lithopone 
Barium carbonate, 121 
analysis of, 315 
manufacture of, 122 
paints, value in, 122 
versus Witherite, 122 
Barium sulph., artificial — see blanc fixe 

natural — see barytes 
Barytes, 112 
analysis of, 312^ 314 
bleaching of, 116 
bulkuig of, in oil and paint, 115 
chirt rockin, 116 
exposure tests of paints containing, 

114 
filler, value as, 113 

versus other fillers, 115 
occurrence, 115 
para red, use of with, 113 



treatment of, 116 

wearing qualities of paints contain- 
ing, 112, 114 
Battleship gray, blanc fixe, use of, in, 
118 
exposure tests of, on "Panther," iig 
manufacture of, 119 
Beck ton white — see lithopone 
Benzine, 238 
and condensation of water due to 

evaporation of, 239 
distillation of, 241 
use in paints, 238 
Benzol, composition, production and 
cost of, 243 
crude, 243 
properties of, 244 
use in black paints, 244 
use in finishing coats (objection to), 

244 
use to prevent livering, 244 
use in priming paints, 244 
Benzol black, 107 

behavior in oil, 108 
Bitumens, chemical composition of, 262 
exposure tests of, 264 
paints, deterioration of, 264 
sunlight, effect of, on, 261, 262 
Black lead, — see graphite 
Black pigments, 97 
analysis of, 309 

Prussian blue in detection of, 309 
varieties of, 97 
acetylene, 108 
benzol, 107, 108 
bone, 97 
carbon, 100 
color in varnish, 98 
Black pigments, varieties of, 
drop, 106, 107 



358 



INDEX 



Black pigments, varieties of, 
ivory, io6 
lamp, 98, 99 
mineral, 109 
sugar house, 97 
toner, 97 
vine, 104 
Blanc fixe, 116 
analysis of, 310 
consumption of, in U. S., 120 
manufacture of, 116, 121 
salt water, effect of, on paints con- 
taining, 120 
use in enamels, 117, 118 
" " lakes, 117, 118 
" " linoleum, 120 
" " oil cloth, 120 
" " paints, as reinforcing pigment, 

118 
" " paper, 116, 117 
" " printing ink, 120 
Bleaching, of oils, 171, 172 
Blood stone — see iron oxids 
Blown oils, analysis of, 1 79 
Blue lead, composition and properties, 61 

pigments, 84 
Boiled linseed oil, specifications for, 1 74, 

175 
Bone black, 97 

Branding, of white lead, 16, 17 

Branding of mixed paint, 17 

Breninig — see silex 

Bromide test, 340 

Bronze blue — see Prussian blue 

Brooke — sec soya beans 

Brown pigments, 71 

Burnt ochre. 74 

Burnt sienna, 71 

American, 71, 72 

Italian, 72, 73 
Burnt umber, 63 

Calcium carl^onatc — see whiting 
resinate, formation of, in concrete 
ll(H)rs, 147 
as i^rotcction for concrete from 
machiner>' oils, 147 
sulphate — sec gypsum 



Carbon black, properties, 100 
dioxid, effect of, on white pigments, 

140 
paints, 141 

wearing qualities of, 141 
Cassel brown — sec Vandyke brown 
Cement paints — see concrete paints 
Cement, Portland, use of, in paints, 146, 

149 
Chalk — see whiting. 
Charcoal, alkalinity in, 104 
manufacture of, 104 
paint pigment, use as, 104 
preservative coating from, and 

litharge, 104 
saponification of, paints in presence 

of moisture, 105 
uses in oil cloth and coated leather, 

Charlton white — see lithopone 
China base oil, 185 
Chinese blue — see Prussian blue 
wood oil, 180 
acidity of, effect in enamels, 185, 

186 
adulteration of, 184 

detection of, 187 
analysis of, 182 
calcium oleate in, 182 
Canton, 181 

chemical composition of, 183 
constants of, 182 
drying of, 180, 181 
gelatinization, 181, 185 
Hankow, 181 
heating of, 181, 184 
odoroF, means of detection, 182, 185 
paints, 181 

enamel, 182 
polN-merization of, 181, 185 
raw, in flat wall paints, 186, 187 
rosin varnish, 187 
specifications for, 190 
uses, 183, 184 

in baking enamels, 187 

in cement floor paints, 187 
waterproof (qualities of, 183 
wearing qualities of, 183 



INDEX 



359 



Chirt rock — see barytes 
Chlorophyll ia linseed oil, 169 
Chrome green, analysis of, 304 
composition of, 92 
permanence of, 93 
Chrome yellow, analysis of, 303 
composition of, 82 
permanence of, 82 
preparation of, 81 
Chromium oxid, 93 
manufacture of, 94 
use in delicate greens, 94 
Cinnabar, 66 
Clay, 127 
analysis of, 128, 312 
presence of, in ochres and siennas, 127 
uses, in paints to prevent settling, 127 
in cheap barrel and paste paints, 
127 
water in, 127 

wearing qualities of paint containing, 
127 
Coal, use of, in paints, 106 
Coarse paints, value as priming coats, 259 
Cobalt blue, 87, 88 
determination of, in paints, 88 
distinction from lithopone, 88 
permanence of, 88 
strength of, 88 
with driers, 89 
Cobalt driers, 247 

amount required to dry oil, 249 
incorporating, in oils, 252 
linoleate, 251 
liquid, 252 
oleate, 251 
oleoresinate, 251 
leslnate, 250 
tungate, 251 

use with soya bean oil, 200 
Cobalt salts, 247 
acetate, 252 
oxid, 252 
oxidation of, 248 
Combining mediums, 254 
rosin-mixing varnishes as, 254 
rubber solutions as, 254 
water as, 254 



Conmionwealth white — see whiting 
Complex ore, low grade, 37 
Concrete floors, abrasion and dusting 
of, 146 

acids, use of, in painting of, 146 

calcium resinate as protection for, 147 

lime, free, in, 147 

machinery oils, effect of, on, 147 

resin acids for coating, 147 

zinc sulphate, use in, 148 
Concrete paints, 146 

consumption of, 148 

use of Chinese wood oil and copals in, 
147, 148 
"Cooler," 18 
Copper, anti-fouling paints, 145 

green, 96 
Com oil, 214 

analytical constants, 215^ 216 

drying of, 235 

■ 

treatment of, 215 
uses, 214 

versus soya bean oil, 215 
Corrosion, electrolytic, of structural 
steel, 276 
electrolytic, at anode, 276, 277, 278 
paint vehicles as protective • agents 
against, 266 
Creosote, use in shingle stain, 156 

Damar enamels, 151 
gum, acid value of, 151 
varnish, preparation of, 152 

Damp-resisting paints, 149, 150 
adhesion of, to brick and mortar, 149, 

ISO 
use of Chinese wood oil and linseed 
oil in, 150 
Diatoms, nature of, and composition, 
126 
use in lakes and paints, 126 
Dickens's "Bright Star in the East," 31 
Drier, cobalt, 247 
Japan, 163 

Japanners' Prussian brown as, 163 
lead sulphate as, 163 
lime oil, 163 
litharge as, 162 



360 



INDEX 



Drier, manganese salts as, 162, 163 

Prussian blue as, 163 

red lead as, 162 

zinc sulphate as, 163 
"Drifts," 19 
Drop black, 106, 107 
Durcx white — see barium carbonate 

Blast Indian red, 65 

Eibner and Muggenthaler — see bro- 
mide test 
Emulsiiiers, 256, 257 
Enamel oil, typical analysis of, 1 79 
Enamel paints, composition, 151 

damar type of, 151 

definitions of, 150 

lithopone, wood oil, rosin type 
of, 152 

stand oil t>'pe of, 152 
Erythrophyll in linseed oil, 171 
Exposure tests of paint vehicles, 266, 

272, 273 
Extenders — see fillers 

Famau — see lithopone 

Ferric oxid paints — see iron oxid 

paints 
Ferric oxids — see iron oxids 
Fillers, as adulterants, iii, 112 

bar>' tes as, 113 

battleship gray, use in, in 

clay, use of, as, 127 

inert, value in paints, 1 10 

occurrence in pigments, iii, 127 

principal, value of, 112 

wearing qualities of paints as affected 
by. 141 
Fine grinding. 259 

for finishing coats, 250 

and rubbing of varnishes, 260 
Fire proof paints. 128. 129 

alum s;ilts, usi' in, 129 

for shingles. 130 
Fish oil, analytical constants of men- 
haden. 207 

analytical constants of varieties of, 
204 

drying of, 208 



herring oil, 210 
pseudo versus genuine, 203 
red lead, use of, in, 207 
sp>ecifications for, 209 
treatment of, 205 
Fish oil, use of, in baking japans, 207 

in enamel leather and printing 

ink, 206 
in exterior paints, 205 
in [>aints, 204 
on seacoast, 207 
in smokestack paints, 207, 208 
in waterproof paints, 207 
Floor paints — see concrete paints 
Foots, in linseed oil, 171 
Fuller's earth, 126, 127 
Fungi, definition of, 284 
fungicides, use of, for, 286 
growth of, on paints, 284 
varieties of, 286 

Gilder's white — see whiting 
Glycerides, influence of sunlight on, 263 
Gmelin — see ultramarine blue 
Graphite, Acheson, 102 

analysis of, 310 

behavior of, in linseed oil with other 
pigments, 101 

brown, 102 

exjwsure of, and iron oxid, 102 

fillers in, use of, 103 

film, adaptability for reixainting. 103 

green, 102 

paint film, 103 

paints, 141 

properties of, loi 

red, 102 
Green aniline lakes, 95 

chrome, 92, 304 
Grinding, fine, 259 

paste, 18, 19 

surfaces of mills, 19 
Ciuinet — see ultramarine blue 
(Jypsum, alabaster as source of, 137 

analysis of, 139, 311 

calcium chloride as source of. 138 

comjKisition and occurrence of, 135 

free lime in, 136 



INDEX 



Gypsum, hydration of, 137 
presence of, in Venetian red, 138 
use of, in freight car color, 138 

as paint filler, 136 
water in, 136 

Harrison Red, 69 
Helio Fast Red, 69, 70 
Hematite — see iron oxids 
Hermann — see ultramarine blue, 85 
Herring oil, 210 

acidity of, 211 

drying of, 214 

treatment of, 213, 214 
Hough process — see pine oil, 229 
Huhlmann — see ultramarine blue, 8$ 
Hygiene, painters', 281 
Hypha — see fungi, 284 
H>'pochlorite of lime, in shingle stain, 
156 

Indian red — see iron oxids, 64 
Infusorial earth, 122 

composition and properties, 1 25 

use of, in paints, 126 
Iodine value, det. of, of oils, 337 
Iron — see corrosion 
Iron oxids, analysis of, 299 

bloodstone, 65 

East Indian red, 65 

hematite, 65 

Indian red, 64 

manufacture of, 63 

paints, 141, 142, 144 

Persian,' 63, 65 

protective pigments, 62 

rouge, watch case, 66 

rubber pigments, 62 

shingle stain, 156 

Venetian reds, 63, 64 
Ivory black, coach color, 106 

extract of, 106 

properties, 106 

Japanners' Prussian brown, 163 
Jersey lily white — see Iithoix)ne 

Kaolin, 127, 128 — sec clay 



361 



Kaolinite, 128 

Kauri dust, use of, in japan driers, 163 

Kieselguhr, 126 

Koettig — see ultramarine blue, 86 

Lake base — see blanc fixe 

Lampblack, 98, 99 

Lapis lazuli, 84 

"Lead," meaning of, 19 

Lead, oxids, 53 
peroxid, det. of, in red lead, 298 
sulphate, basic, anal, of, 290, 26, 35, 

38,39 
drier, 163 

Les Val6es — see soya beans, 194 

Leverkus — see ultramarine blue, 86 

Leverkusen — see ultramarine blue, 86 

Leykauf, see ultramarine blue, 87 

Leykauf and Zeltner — see ultramarine 

blue, 86 

Liebermann, Storch reaction, 330 

Light — see sunlight 

"Light wood " — see pine oil, 231 

Lime oil, 163 

Linseed oil, adulteration of, 159 

analysis, typical of, 1 74 

analytical constants of, 158, 161 

Baltic, 158 

bleaching of, 171 

blown, typical analysis of, 1 79 
^ boiled, specifications for, 1 74, 1 75 
* "breathing of," 168, 169 

Calcutta, 159 

carbon dioxid from, 168, 169 

coloring matter in, 169, 171 

deterioration of, 173 

driers and drying of, 162, 163 

extraction of, 160 

film, porosity of, 164, 166 

new process, 160 

N. American, 158 

paints, 164, 165 

patent leather, use of, in, 165 

reactions of, with pigments in can, 

173 
refining of, 169 

saponification of, 164 

specifications for, 174, 175 



362 



INDEX 



Linseed oil, treating of, 165 

waterproof qualities of, 164, 165 
Liquid paint, 23 
Litharge, as drier, 162 
-cement, 56 

flake, 54 

livering of, in mixed paints, 53 

manufacture of, 53 

testing of, 53 

use, in black paints, 53 

in preservative paints, 53 
Lithol red, 70 
Lithopone, 26, 46 

analysis of, 296 

barium sulphate in, 48 

composition of, 46 

darkening of, by sunlight, 49 ' 

enamels, 152 

manufacture of, 46, 47 

paint pigment, 49 

yellow color of, cause, 49 

zinc oxid in, 48, 51 
Long oil, 177, 178 



fillers in, 14, 16, 141 

fire- resisting, 155 

flat, wall, 154 

floor, 15s 

graphite, 141 

guarantees of manufacturers, 143 

iron oxid, 144 

manufacture of, 18 

origin of, 13 

Portland cement, 146, 149 

primer on wood, 143 

shingle, 155 

storage of, 20, 21, 22 

tinting, tanks for, locating, 20 

water in, 13, 17 

wearing qualities of, effect of fillers 

on, 141 
white, exposure tests of, 140 
white lead, effect of rain water and 

carbon dioxid on, 140 
zinc vs. white lead, 140, 142 
Mixers, liquid, 18 
for mixed paint, 20 



Maize oil — see com oil 
Manganese salts, as driers, 162, 163 
Marble dust, as filler, 130, 133, 134 
Marble oil, 176 
Mercur>' sulphide, 66 

analysis of, 302 
^lildew. formation of, 284 
Mills, for grinding paints, iq, 20 
Milori blue — see Prussian blue 
Mineral black, C()miK)sition and prop- 
erties, log 
Mixed paints, analysis of, 324 

anti-f.)ulin^. 144, 145 

ben/.ol. in. 244 

bleadiin^ of white, 173 

brandinK of. 17 

carl>on, 141 

coiKTete, 146 

consumption of. 14. 14^ 

covering qualities of. 141 

(lamp-resistinj;. 140, 150 

distribution of. in factory. 20 

enamel, 150, 151, 152, 153 

ferric oxid, i2i, 142 



Naphtha — see benzine 
Nitroparatoluidine — see Hello Fast Red 

O'Brien — see lithopone, 49 
Ochre, American yellow, 78 

burnt, 74 

clay in, 127 

cream, 79 

French, brands of, 79, 80 

golden, 79 

gray, 79 

grt^n, 80 

white, 79 
Oils, acid value, det. of, 336 

analysis of, 334 

blown, typical analysis of, 179 

bromide test for, 340 

Chinese wcxxl, 180 

corn. 214 

enamel. ty[)ical analysis of, 179 

fish. 203 

herring, 210 

icMline value, det. of, 337 

Ja[)anese wood, 180 



INDEX 



363 



Oils, Japanners* Prussian brown, 178 

linseed, 158 

long, 177 

maize, 215 

marble, 176 

menhaden, 203 

pine, 228 

short, 177 

soya bean, 192 

specific gravity, det. of, 334 

stand, 176 

Tung, 180 

Turpentine, 217 
Oleum white — see lithopone 
Orange mineral — see red lead 
Orr — see lithopone, 46 
Orr's white — see lithopone 
Ozark white, 26, 39 

composition and manufactureof,4o,4i 

Paint, bactericidal action of, 284 

bitumen, exposure tests of, 264 

coarse, as priming coats, 259 

fillers, use in, 14 

fine, as finishing coats, 259 

floor, 19 

fungi in, 284 

mildew on, 284 

mixed — see mixed paints 

paste, manufacture of, 18, 19 

pigments, analysis of, 317 

sunlight, influence of, 261 

varnish, 19 
Painters' hygiene, 281, 282 
" Panther," exposure test of Battleship 

gray on, 119 
Paranitraniline red, 67 

barytes, use of, in, 113 

bleeding of, 69 

manufacture of, 68 

reactions, 67 

permanence of, 68 

uses of, 69 
Paris blue — see Prussian blue 

white — see whiting 
Paste grinding, 18, 19, 23 
advantages of, 25 

mills, 23, 24, 25 



Patent leather, use of linseed oil in, 165 

Penecilium crustaceum, 286 

"Periphery," 19 

Permanent white — see blanc fixe 

Persian oxids, 63, 65 

Pigments, analysis of, 317 

reinforcing, no 
Pine oil, analysis of, 237 
distillation of, fractional, 237 
extraction of, 228, 230 
bath process, 231 
destruct.-distill. process, 230 
Hough process, 229 
formation of, 233 
light wood as source of, 231 
long leaf, 232 

relation to turpentine and rosin, 232 
solvent properties of, 234 
terpineol in, 233 
use of, in paints, 234, 235 
water in, detection of, 234, 235, 332 
Ponolith — see lithopone 
Potassium dichromate, use in shingle 

stains, 156 
Priming coat for wood, 143 
Princess metallic, 71, 74 
composition of, 76 
mining and milling of, 75 
paints, wearing qualities of, 144 
properties and uses of, 75 
Princess mineral brown, 74 
Prussian blue, analysis of, 91, 306 

composition and manufacture of, 

properties of and uses, 90, 91 

varieties of, 90 
Prussian brown, japanners, as drier, 163 
Prussian brown oil, japanners, 178 
Putty, whiting, 132 

Quartz, 123 

Quicksilver vermilion, 66 

Raw sienna, 78 

Red lead, analysis of, 298 

drier, use of, for oil, 162 

Dutch boy. 56 

field test vs. laborator>' test, 60 



366 INI 

Whiti; leaiJ; soap, formation of, 30 

sublimed, 26, 35, 38, jg 
analysis of, 2Qb 

suli^uu gaset, effect of, on, 33 
' tozidty of, 30, $1 

vuieties of, »6 

Venus zinc ond, 143 

weathering of, 32, 33 
White minersl primer-— see whiting . 
VUte piEments, 26, 27, 28 

venus other lilleis, 134 
WUting, addity la paints, corrected by, 

Uia1)w of, 31 1 

t^-product, 134 . . 

duratnUty of, in oil, 131 

filler, 13a, 133, 134 ' 

Dunufaaute of, 130, 131 

putty, 132 

idiile miner&l primer, 134 
Williams — see anti-footiag paints, 144 
Witherite, 122 

Wc4f and Scbobe.niethod, fitt iMin, 329 
Wood oil, todn *"wb"'1», 15a 
Wood turpentine, compo»tion, 113 

manufacture of, 221 

uses in paints, 123 



YeQoiv, chrome, 81, 82, 3C(3. 
odirc, 7a 
oxid So 
IHgmcnts, 78 



Snc chrcHnatc, as 

green, composition, prapeities, u 

95 
leac},i6- 

aaalysia of, 191 
oomplex ore, 37 
- composition of , 38 
minufactuie of, 37 
white, standard, 37 
MiDes^ Ppii)t> '6 
oiid,4t 

kna!yins irf, 193 
brands, ,|4, 43 , 



Xantophyll, in linseed oi 
Xylol, 246 



169 



consumption of, 41 
oijdatjoa of, in oil, 41 

vs. oth« driers, 41, 43 
P^t,i3 
eipoiure test of, 14a 
vs. white lead paint, 141 

sulphur gases, effect of, on, 
zinc sulphate in, 44, 45 
sulphate, as drier, 163 
Zinojc, 45 



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Batey, J. The Science of Woiks Management lamo, 

Beadle, C. Chapters on Papermaking. Five Volumes i2mo, each, 

Beaumont, R. Color in Woven Design 8vo, 

Finishing of Textile Fabrics 8vo, 

Beaumont, W. W. The Steam-Engine Indicator 8vo, 

Bechhold, H. Colloids in Biology and Medicine. Trans, by J. G. 

Bullowa (In Press.) 

Beckwith, A. Pottery 8vo, paper, o 60 

Bedell, F., and Pierce, C. A. Direct and Alternating Current ManuaL 

8vo, 

Beech, F. Dyeing of Cotton Fabrics. 8vo, 

Dyeing of Woolen Fabrics 8vo, 

Begtrup, J. The Slide Valve 8vo, 

Beggs, G. £. Stresses in Railway Girders and Bridges (In Press.) 

Bender, C. E. Continuous Bridges. (Science Series No. 26.) i6mo, o 50 

Proportions of Pins used in Bridges. (Science Series No. 4.) 

i6mo, o 50 
Bengough, G. D. Brass. (Metallurgy Series.) {In Press.) 

Bennett, H. G. The Manufacture of Leather 8vo, 

Bernthsen, A. A Text - book of Organic Chemistry. Trans, by G. 

M'Gowan i2mo, 

Berry, W. J. Differential Equations of the First Species. i2mo. {In Preparation.) 
Bersch, J. Manufacture of Mineral and Lake Pigments. Trans, by A. C. 

Wright 8vo, 

Bertin, L. E. Marine Boilers. Trans, by L. S. Robertson 8vo, 

Beveridge, J. Papermaker's Pocket Book i2mo, 

Binnie, Sir A. Rainfall Reservoirs and Water Supply 8vo, 

Binns, C. F. Manual of Practical Potting 8vo, 

The Potter's Craft i2mo, 

Birchmore, W. H. Interpretation of Gas Analysis i2mo, 

Blaine, R. G. The Calculus and Its Applications i2mo, 



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D. VAN NOSTRAND CO.'S SHORT TITLE CATALOG 



5 



Blake, W. H. Brewers' Vade Mecum 8vo, *4 oo 

Blasdale, W. C. Quantitative Chemical Analysis. (Van Nostrand's 

Textbooks.) i2mo, *2 50 

Bligh, W. G. The Practical Design of Irrigation Works 8vo, *6 00 

Bloch, L. Science of Blumination. Trans, by W. C. Clinton 8vo, *2 50 

Bloky A. Illumination and Artificial Lighting i2mo, i 25 

Bliicher, H. Modem Industrial Chemistry. Trans, by J. P. Millington. 

8vo, ♦? 50 

Blythy A. W. Foods: Their Composition and Analysis Svo, 7 50 

Poisons: Their Effects and Detection 8vo, 7 50 

BOckmann, F. Celluloid i2mo, *2 50 

Bodmer, G. R. Hydraulic Motors and Turbines i2mo, 5 00 

Boileau, J. T. Traverse Tables 8vo, 5 00 

Bonney, G. £. The Electro-platers' Handbook i2mo, i 20 

Booth, N. Guide to the Ring-spinning Frame i2mo, *i 25 

Booth, W. H. Water Softening and Treatment 8vo, *2 50 

Superheaters and Superheating and Their Control 8vo, *i 50 

Bottcher, A. Cranes: Their Construction, Mechanical Equipment and 

Working. Trans, by A. Tolhausen 4to, *io 60 

Bottler, M. Modem Bleaching Agents. Trans, by C. Salter. . . . i2mo, *2 50 

Bottone, S. R. Magnetos for Automobilists i2mo, *i 00 

Boulton, S. B. Preservation of Timber. (Science Series No. 82.) . i6mo, o 50 

Bourcart, E. Insecticides, Fungicides and Weedkillers 8vo, % 50 

Bourgougnon, A. Physical Problems. (Science Series No. 113.)- i6mo, 050 
Bourry, E. Treatise on Ceramic Industries. Trans, by A. B. Searle. 

8vo, *5 00 

Bowie, A. J., Jr. A Practical Treatise on Hydraulic Mining Svo, 5 00 

Bowles, O. Tables of Common Rocks. (Science Series No. i25.).i6mo, o 50 

Bowser, E. A. Elementary Treatise on Analjrtic Geometry i2mo, i 75 

Elementary Treatise on the Differential and Integral Calculus . 1 2mo, 2 25 

Elementary Treatise on Analjrtic Mechanics i2mo, 3 00 

Elementary Treatise on Hydro-mechanics i2mo, 2 50 

A Treatise on Roofs and Bridges i2mo, *2 25 

Boycott, G. W. M. Compressed Air Work and Diving Svo, *4 . 00 

Bragg, E. M. Marine Engine Design i2mo, *2 00 

Design of Marine Engines and Auxiliaries (In Press.) 

Brainard, F. R. The Sextant. (Science Series No. loi.) i6mo, 

Brassey's Naval Annual for 1915 Svo, 

Brew, W. Three-Phase Transmission Svo, *2 00 

Briggs, R., and Wolff, A. R. Steam-Heating. (Science Series No. 

67.) i6mo, 50 

Bright, C. The Life Story of Sir Charles Tilson Bright Svo, *4 50 

Brislee, T. J. Introduction to the Study of Fuel. (Outlines of Indus- 
trial Chemistry. ) Svo, *3 00 

Broadfoot, S. K. Motors, Secondary Batteries. (Installation Manuals 

Series.) lamo, *o 75 

Broughton, H. H. Electric Cranes and Hoists *9 00 

Brown, G. Healthy Foundations. (Science Series No. 80.) i6mo, o 50 

Brown, H. Irrigation Svo, *5 00 

Brown, Wm. N. The Art of Enamelling on Metal i2mo, *i 00 



3 50 


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8 D VAN NOSTRAND CO/S SHORT TITLE CATALOG 

Courtney, C. F. Masonry Dams 8vo, 

Cowell, W. B. Pure Air, Ozone, and Water i2mo, 

Craig, J. W., and Woodward, W. P. Questions and Answers About 

Electrical Apparatus i2mo, leather, 

Craig, T. Motion of a Solid in a Fuel. (Science Series No. 49.) . i6mo, 

Wave and Vortex Motion. (Science Series No. 43.) i6mo. 

Cramp, W. Continuous Current Machine Design Sto, 

Creedy, F. Single Phase Commutator Motors 8vo, 

Crocker, F. B. Electric Lighting. Two Volumes. 8vo. 

Vol. L The Generating Plant 301 

Vol. n. Distributing Systems and Lamps 

Crocker, F. B., and Arendt, M. Electric Motors Sto, *2 50 

Crocker, F. B., and Wheeler, S. S. The Management of Electrical Ma- 
chinery i2mo, •! 00 

Cross, C. F., Bevan, E. J., and Sindall, R. W. Wood Pulp and Its Applica- 
tions. (Westminster Series.) Sto, ^2 00 

Crosskey, L. R. Elementary Perspective 8vo, i 00 

Crosskey, L. R., and Thaw, J. Advanced Perspective 8vo, i 50 

Culley, J. L. Theory of Arches. (Science Series No. 87.) i6mo, o 50 

Dadourian, H. M. Analytical Mechanics i2mo, *3 00 

Dana, R. T. Handbook of Construction plant i2mo, leather, *5 00 

Danby, A. Natural Rock Asphalts and Bitiunens 8vo, 

Davenport, C. The Book. (Westminster Series.) 8vo, 

Davey, N. The Gas Turbine 8vo, 

Davies, F. H. Electric Power and Traction 8vo, 

Foundations and Machinery Fixing. (Installation Manual Series.) 

6mo, 

Dawson, P. Electric Traction on Railways 8vo, 

Deerr, N. Sugar Cane 8vo, 

Deite, C. Manual of Soapmaking. Trans, by S. T. King 4to, 

De la Coux, H. The Industrial Uses of Water. Trans, by A. Morris. 8vo, 

Del Mar, W. A. Electric Power Conductors 8vo, 

Denny, G. A. Deep-level Mines of the Rand 4to, *io 00 

Diamond Drilling for Gold *5 00 

De Rocs, J. D. C. Linkages. (Science Series No. 47.) i6mo, o 50 

Derr, W. L. Block Signal Operation Oblong 1 2mo, 

Maintenance-of-Way Engineering {In Prcjxiradon.) 

Desaint, A. Three Hundred Shades and How to Mix Thera 8vo, 

De Varona, A. Sewer Gases. (Science Series No. 55.) i6mo, 

Devey, R. G. Mill and Factory Wiring. (Installation Manuals Series.; 

i2mo, 
Dibdin, W. J. Purification of Sewage and Water 8vo, 

Dichmann, Carl. Basic Open-Hearth Steel Process i2mo, 

Dieterich, K. Analysis of Resins, Balsams, and Gum Resins. . . . 8vo, 
Dinger, Lieut. H. C. Care and Operation of Naval Machinery i2mo, 
Dixon, D. B. Machinist's and Steam Engineer's Practical Calculator. 

i6mo, morocco, i 25 
Doble, W. A. Power Plant Construction on the Pacific Coast {In /'/•«.<> ■ 



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D. VAN NOSTRAND CO.'S SHORT TITLK CATALOG 9 

Dodge, G. F. Diagrams for Designing Reinforced Concrete Structures, 

folio, *4 00 
Dommett, W. £. Motor Car Mechanism iimo, *i 25 

Dorr, B. F. The Surveyor's Guide and Pocket Table-book. 

i6mo, morocco, 2 00 

Down, P. B. Handy Copper T^e Table i6mo, 

Draper, C. H. Elementary Text-book of Light, Heat and Sound . . i2mo, 
Heat and the Principles of Thermo -dynamics lamo, 

Dron, R. W. Mining Formulas i2mo, 

Dubbel, H. High Power Gas Engines 8vo, 

Duckwall, £. W. Canning and Preserving of Food Products 8vo, 

Dumesny, P., and Noyer, J. Wood Products, Distillates, and Extracts. 

8vo, 

Duncan, W. G., and Penman, D. The Electrical Equipment of Collieries. 

8vo, 

Dunstan, A. £., and Thole, F. B. T. Textbook of Practical Chemistry. 

i2mo, 
Duthie, A. L. Decorative Glass Processes. (Westminster Series.) . 8vo, 

Dwight, H. B. Transmission Line Formulas Svo, 

Dyson, S. S. Practical Testing of Raw Materials 8vo, 

Dyson, S. S., and Clarkson, S. S. Chemical Works 8vo, 

Eccles, R. G., and Duckwall, E. W. Food Preservatives 8vo, paper, o 50 

Eccles, W. H. Wireless Telegraphy and Telephony i2mo, ^4 50 

Eck, J. Light, Radiation and Illumination. Trans, by Paul Hogner, 

Svo, 

Eddy, H. T. Maximum Stresses under Concentrated Loads Svo, 

Edelman, P. Inventions and Patents i2mo i2mo, 

Edgcumbe, K. Industrial Electrical Measuring Instruments Svo, 

Edler, R. Switches and Switchgear. Trans, by Ph. Laubach . . . Svo, 

Eissler, M. The Metallurgy of Gold Svo, 

The Metallurgy of Silver Svo, 

The Metallurgy of Argentiferous Lead Svo, 

A Handbook on Modem Explosives Svo, 

Ekin, T. C. Water Pipe and Sewage Discharge Diagrams folio, 

Electric Light Carbons, Manufacture of Svo, 

Eliot, C. W., and Storer, F. H. Compendious Manual of Qualitative 

Chemical Analysis i2mo, 

Ellis, C. Hydrogenation of Oils Svo, 

Ellis, G. Modem Technical Drawing Svo, 

Ennis, Wm. D. Linseed Oil and Other Seed Oils Svo, 

Applied Thermodjmamics Svo, 

Flying Machines To-day iimo, 

Vapors for Heat Engines lamo, 

Erfurt, J. Dyeing of Paper Pulp. Trans, by J. Hubner 

Ermen, W. F. A. Materials Used in Sizing Svo, 

Erwin, M. The Universe and the Atom i2mo, 

Evans, C. A. Macadamized Roads {fn Press.) 



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lo D. VAN NOSTRAND CO.'S SHORT TITLE CAT \LOG 
Ewing, A. J. Magnetic Induction in Iron ... 8vo, ' 

Fairie, J. Notes on Lead Ores umo, ■ 

— Notes on Pottery Clays i2mo, ' 

Fairley, W,, and Andre, Geo. J. Ventilation of Coal Mines. tScieace 

Series No. s8-l , t6mo, 

Fairweather, W. C. Foreign and Colonis] Patent Laws Svo, * 

Faik, M. S. Cement Mortars and Concretes Bvo, * 

Fanning, J. T. Hydraulic and Water-supply Engineering 8vo, " 

Fay, I. W. The Coal-tar Colors 8to, • 

Fembach, R. L. Glue and Gelatine 8vo, * 

Ctaentical Aspects of Silk Manufacture . lamo, ■ 

Fischer, E. The Preparation of Organic Compounds. Trans, by R. V, 

Stanford iimo, * 

Fish, J. C. L. Lettering of Working Drawings .Oblong 8vo. 

Mathematics of the Paper Location of a Railroad, .paper, iicno, * 

Fisher, H. K. C, and Darby, W. C. Submarine Cable Testing 8vo, * 

Fleischmann, W, The Book of the Dairy. Trans, by C. M. Aikman. 

Svo, 
Fleming, J. A. The Alternate-current Transformer. Two Volumes, 8vo. 

Vol. I. The Induction of Electric Currents , . ' 

Vol. U. The Utilization of Induced Currents. . * 

Fleming, J. A, Propagation of Electric Currents 8vo, ", 

A Handbook for the Electrical Laboratory and Testing Room. Two 

Volumes 8vo, eacb, ■; 

Fleury, P. Preparation and Uses of While Zinc Paints Svo, * 

Flynn, P. J. Flow of Water. (Science Series No. 84.) . . unio, 1 

■ Hydraulic Tables, (Science Series No. 66.) . .... . . . .i6mo, 1 

Forgie, |. Shield Tunneling Bvo. (/ii I'tess.) 

Foster, H. A. Electrical Engineers' Pocket-book. (.sVwhM EdUion.) 

iimo, leather, 

Engineering Valuation of Public Utilities and Factories . , . 8vo, * 

Handbook of Electrical Cost Data 8vo (/" /V*(.) 

Foster, Gen. J. G. Submarine Blasting in Boston iMass.) Harbor 4(0, 
Fowie, F. F. Overhead Transmission Line Crossings iimo, * 

The Solution of Alternating Current Problems 8vo {in PnsfA 

Fox, W. G. Transition Curves. (Science Series No. 1 10.) t6mo, 1 

Fox, W.. and Thomas, C. W. Practical Course in Mechanical Draw- 
ing """Of 

Foye, J. C. Chemical Problems. (Science Series No. 6g.j . . . i6mo, • 

Handbook of Mineralogy. (Science Series No. 86.). . . . i6mOi ■ 

Francis, J. B. Lowell Hydraulic Experiments , 4(0, 11 

Franzen, H. Exercises in Gas Analysis . lamo, ' 

French, J, W. Machine Toots, a vols 4to, "i 

Freudemacber, P. W. Electrical Mining Installations. < Installation 

Manuals Series.) ..... . . . . timo, * 

Frith, J. Alternating Current Design 8vo, '; 

Fritsch, J. Manufacture of Chemical Manures. Trans, by D. Grant. 

8»o, •■ 



D. VAN NOSTRAND CO/S SHORT TITLE CATALOG n 

Ftye, A. L Civil Engineers' Pocket-book lamo, leather, •$ oo 

Fuller, G. W. Investigations into the Purification of the Ohio River. 

4to, *io 00 

Fumell, J. Paints, Colors, Oils, and Varnishes 8vo. *i oo 

Gairdner, J. W. I. Earthwork 8vo (/n Press.) 

Gant, L. W. Elements of Electric Traction 8vo, *a 50 

Garcia, A. J. R. V. Spanish-English Railway Terms 8vo, *4 50 

Garforth, W. E. Rules for Recovering Coal Mines after Explosions and 

Fires lamo, leather, i 50 

Garrard, C. C. Electric Switch and Controlling Gear (/n Press.) 

Gaudard, J. Foundations. (Science Series No. 34.) i6mo, 050 

Gear, H. B., and Williams, P. F. Electric Central Station Distribution 

Systems 8vo, *3 00 

Geerligs, H. C. P. Cane Sugar and Its lianufacture 8vo, *5 00 

Geikie, J. Structural and Field Geology 8vo, *4 00 

Mountains. Their Growth, Origin and Decay 8vo, *4 00 

The Antiquity of Man in Europe 8vo, *3 00 

Georgi, F., and Schubert, A. Sheet Metal Working. Trans, by C. 

Salter 8vo, 300 

Gerber,N. Analysis of Milk, Condensed Milk, and Infants' Milk-Food. 8vo, i 25 
Gerhard, W. P. Sanitation, Watersupply and Sewage Disposal of Country 

Houses i2mo, *2 00 

Gas Lighting (Science Series No. iii.) i6mo, o 50 

Household Wastes. (Science Series No. 97.) i6mo, o 50 

House Drainage. (Science Series No. 63.) i6mo, o 50 

Geihard, W« P* Sanitary Drainage of Buildings. (Science Series No. 93.) 

i6mo, o 50 

Gerhardi, C. W. H. Electricity Meters 8vo, '*'4 00 

Geschwind, L. Manufacture of Alum and Sulphates. Trans, by C. 

Salter 8vo, *$ 00 

Gibbs, W. E. Lighting by Acetylene i2mo, *i 50 

Gibson, A. H. Hydraulics and Its Application 8yo, '''s 00 

Water Hammer in Hydraulic Pipe Lines i2mo, *2 00 

Gibson, A. H., and Ritchie, E. G. Circular Arc Bow Girder 4to, *3 50 

Gilbreth, F. B. Motion Study i2mo, *a 00 

Bricklaying System Svo, *3 00 

Field System lamo, leather, *3 00 

Primer of Scientific Management i2mo, *i 00 

Gillette, H. P. Handbook of Cost Data i2mo, leather, '*'5 00 

Rock Excavation Methods and Cost i2mo, *3 00 

and Dana, R. T. Cest Keeping and Management Engineering . Svo, *3 50 

and Hill, C. S. Concrete Construction, Methods and Cost Svo, *5 00 

Gillmore, Gen. Q. A. Limes, Hydraulic Cements acd Mortars Svo, 4 00 

Roads, Streets, and Pavements i2mo, 2 00 

Godfrey, E. Tables for Structural Engineers i6mo, leather, *2 50 

Golding, H. A. The Thcta-Phi Diagram i2mo, *i 25 

Goldschmidt, R. Alternating Current Commutator Motor Svo, *3 00 

Goodchild, W. Precious Stones. (Westminster Series.) Svo, *2 00 



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12 D. VAX NOSTRAND CO.'S SHORT TITLE CATALOG 

Goodeve, T. M. Textbook on the Steam-engine 12 mo, 

Gore, G. Ilectrolytic Separation of Metals 8?o, 

Gould, E. S. Arithmetic of the Steam-engine i2mo, 

Calculus. (Science Series No. 112.) i6mo, 

High Masom'y Dams. (Science Series No. 22.) i6mo, 

Practical Hydrostatics and Hydrostatic Formulas. (Science Series 

No. 117.) , . . i6mo, 

Gratacap, L. P. A Popular Guide to Bftinerals 8vo, 

Gray, J. Electrical Influence Machines i2mo, 

Marine Boiler Design lamo, 

Greenhill, G. Djmamics of Mechanical Flight 8vo, 

Greenwood, £. Classified Guide to Technical and Commercial Books. 8vo, 

Gregorius, R. Mineral Waxes. Trans, by C. Salter i2mo, 

Griffiths, A. B. A Treatise on Manures i2mo, 

Dental Metallurgy 8vo, 

Gross, E. Hops 8vo, 

Grossman, J. Ammonia and Its Compounds i2mo, 

Groth, L. A. Welding and Cutting Metals by Gases or Electricity. 

(Westminster Series) 8vo, 

Grover, F. Modem Gas and Oil Engines 8vo, 

Gruner, A. Power-loom Weaving 8vo, ♦j 00 

Gttldner, Hugo. Internal Combustion Engines. Trans, by H. Diedertchs. 

4to, *io 00 
Gunther, C. 0. Integration 

Garden, R. L. Traverse Tables folio, half morocco, 

Guy, A. £. Experiments on the Flexure of Beams 8vo, 

Haenig, A. Emery and Emery Industry 8vo, 

Hainbach, R. Pottery Decoration. Trans, by C. Salter iimo, 

Hale, W. J. Calculations of General Chemistry i2mo, 

Hall, C. H. Chemistry of Paints and Paint Vehicles iimo, 

Hall, G. L. Elementary Theory of Alternate Current Working. .. .8vo, 

Hall, R. H. Governors and Governing Mechanism i2mo, 

Hall, W. S. Elements of the Differential and Integral Calculus 8vo, 

Descriptive Geometry 8vo volume and a 4to atlas, 

Haller, G. F., and Cunningham, E. T. The Tesla Coil i2mo, 

Halsey, F. A. Slide Valve Gears i2mo, 

The Use of the Slide Rule. (Science Series No. 114.) i6mo, 

Worm and Spiral Gearing. (Science Series No. 116.) i6mo, 

Hamilton, W. G. Useful Information for Railway Men i6mo, 

Hammer, W. J. Radium and Other Radio-active Substances 8vo, 

Hancock, H. Textbook of Mechanics and Hydrostatics 8vo, 

Hancock, W. C. Refractory Materials. ( Metallurgy Series. ) ( /;i Press.) 

Hardy, E. Elementary Principles of Graphic Statics i2mo, 

Haring, H. Engineering Law. 

Vol. I. Law of Contract 8vo, 

Harris, S. M. Practical Topographical Surveying i In Press.) 

Harrison, W. B. The Mechanics* Tool-book i2mo. 

Hart, J. W. External Plumbing Work 8vo, 

Hints to Plumbers on Joint Wiping 8vo, 



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D. VAN XOSTRAND CO/S SHORT TITLE CATALOG 13 

Principles of Hot Water Supply 8vo, *3 00 

Sanitary Plumbing and Drainage 8vo, *3 00 

Haskins, C. H. The Galvanometer and Its Uses i6mo, i 50 

Hatt, J. A. H. The Colorist square i2mo, *i 50 

Hausbrand, £. Drying by Means of Air and Steam. Trans, by A. C. 

Wright i2mo, *2 00 

Evaporating, Condensing and Cooling Apparatus. Trans, by A. C. 

Wright 8vo, *5 00 

Hansmann, £. Telegraph Engineering Svo, *s 00 

Hausner, A. Manufacture of Preserved Foods and Sweetmeats. Trans. 

by A. Morris and H. Robson Svo, *3 00 

HawkeswOTth, J. Graphical Handbook for Reinforced Concrete Design. 

4to, *2 50 

Hay, A. Alternating Currents 8vo, *2 50 

Electrical Distributing Networks and Distributing Lines 8vo, ^3 50 

Continuous Current Engineering 8vo, *2 50 

Hayes, H. V. Public Utilities, Their Cost New and Depreciation. . .8vo, '"a 00 
Public Utilities, Their Fair Present Value and Return Svo, *2 00 

Heather, H. J. S. Electrical Engineering Svo, *3 50 

Heaviside, O. Electromagnetic Theory. Vols. I and U Svo, each, *5 00 

Vol. m Svo, *7 50 

Heck, R. C. H. The Steam Engine and Turbine Svo, '''3 50 

Steam-Engine and Other Steam Motors. Two Volumes. 

VoL I. Thermodynamics and the Mechanics Svo, ^3 50 

Vol. II. Form, Construction, and Working Svo, *5 00 

Notes on Elementary Kinematics Svo, boards, '''i 00 

Graphics of Machine Forces Svo, boards, *i 00 

Heermann, P. Dyers' Materials. Trans, by A. C. Wright i2mo, *2 50 

Heidenreich, £. L. Engineers' Pocketbook of Reinforced Concrete, 

i6mo, leather, *3 00 

Hellot, Macquer and D' Apligny. Art of Dyeing Wool, Silk and Cotton. Svo, *2 00 

Henrici, O. Skeleton Structures Svo, i 50 

Bering, D. W. Essentials of Physics for College Students Svo, *i 75 

Hering-Shaw, A. Domestic Sanitation and Plumbing. Two Vols.. .Svo, *$ 00 

Hering-Shaw, A. Elementary Science Svo, *2 00 

Herrmann, G. The Graphical Statics of Mechanism. Trans, by A. P. 

Smith i2mo, 2 00 

Herzfeld, J. Testing of Yarns and Textile Fabrics Svo, *3 50 

Hildebrandt, A. Airships, Past and Present Svo, "^3 50 

Uildenbrand, B. W. Cable-Making. (Science Series No. 32.) i6mo, o 50 

Hilditch, T. P. A Concise History of Chemistry iimo, *i 25 

Hill, C. S. Concrete Inspection i6mo, *! 00 

Hill, J. W. The Purification of Public Water Supplies. New Edition. 

(In Press,) 
Interpretation of Water Analysis (in Press.) 

Hill, M. J. M. The Theory of Proportion Svo, *2 50 

Hiroi, I. Plate Girder Construction. ( Science Series No. 95.) . . . i6mo, o 50 

Statically-Indeterminate Stresses i2mo, *2 00 

Hirshfdd, C. F. Engineering Thermodynamics. (Science Series No. 45.) 

i6mo, o 50 



14 D. VAN NOSTRAND CO/S SHORT TITLE CATALOG • 

Hobart, H. M. Heavy Electrical Engineering 8vo, *4 53 

' — Design of Static Transformers i2mo, *2 oo 

Electricity 8vo, *a 00 

Electric Trains 8vo, *i 5") 

Hobart, H. M. Electric Propulsion of Ships ; . . .8vo, *2 00 

Hobart, J. F. Hard Soldering, Soft Soldering and Brazing x2mo, *i oo 

Hobbs, W. R. P. The Arithmetic of Electrical Measurements i2mo, o 50 

Hoif, J. N. Paint and Varnish Facts and Formulas i2mo, *i 50 

Hole, W. The Distribution of Gas 8vo, *7 50 

HoUey, A. L. Railway Practice folio, 6 00 

Holmes, A. B. The Electric Light Popularly Explained. ..iimo, paper, 50 

Hopkins, N. M. Experimental Electrochemistry 8vo, 

Model Engines and Small Boats i2mo, i 25 

Hopkinson, J., Shoolbred, J. N., and Day, R. E. Dynamic Electricity. 

( Science Series No. 71.) i6mo, o 50 

Homer, J. Practical Ironfounding •. . .8vo, *2 00 

Gear Cutting, in Theory and Practice 8vo, *3 00 

Houghton, C. E. The Elements of Mechanics of Materials x2mo, *2 00 

Houllevigue, L. The Evolution of the Sciences 8vo, *2 00 

Houstoun, R. A. Studies in Light Production i2mo, 2 00 

Hovenden, F. Practical Mathematics for Young Engineers i2mo, *i 00 

Howe, G. Mathematics for the Practical Man i2mo, *i 25 

Ho worth, J. Repairing and Riveting Glass, China and Earthenware. 

8vo, paper, *o 50 

Hubbard, E The Utilization of Wood-waste Svo, *2 00 

Hiibner, J. Bleaching and Dyeing of Vegetable and Fibrous Materials. 

(Outlines of Industrial Chemistry.) Svo, *5 00 

Hudson, 0. F. Iron and Steel. (Outlines of Industrial Chemistry.). Svo, *2 00 
Humphrey, J. C. W. Metallography of Strain. (Metallurgy Series.) 

( In Press. ) 

Humphreys, A. C. The Business Features of Engineering Practice. Svo, *i 25 

Hunter, A. Bridge Work Svo. ( fn Prrss. ) 

Hurst, G. H. Handbook of the Theory of Color Svo, *2 50 

— Dictionary of Chemicals and Raw Products Svo, *3 od 

Lubricating Oils, Fats and Greases Svo, *4 00 

Soaps Svo, *5 00 

Hurst, G. H., and Simmons, W. H. Textile Soaps and Oils Svo, *2 50 

Hurst, H. E., and Lattey, R. T. Text-book of Physics Svo, *3 00 

Also published in three parts. 

Part L Dynamics and Heat * J 25 

Part II. Sound and Light ' i 25 

Part III. Magnetism and Electricity ' i 50 

Hutchinson, R. W., Jr. Long Distance Electric Power Transmission. 

i2mo, *3 Oo 
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ilri Prfss.) 
Hutchinson, W. B. Patents and How to Make Money Out of Them. 

i2mo, I 25 

Button, W. S. Steam-boiler Construction 8vo, 6 00 

The Works* Manager's Handbook Svo, 6 00 



♦a 


00 





5© 


*2 


50 


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2 


50 


*2 


SO 



D VAN NOSTRAND CO/S SHORT TITLE CATALOG 15 

Hyde, £. W. Skew, Arches. (Science Series No. 15.) i6mo, o 50 

Hyde, F. S. SolventSy Oils, Gums, Waxes 8vo, 

ladttction Coils. (Science Series No. 53.) i6mo, 

Ingham, A. £. Gearing. A practical treatise 8vo, 

Ingle, H. Mannal of Agricultural Chemistry 870, 

Inness, C. H. Problems in Machine Design i2mo, 

Air Compressors and Blowing Engines i2mo, 

Centrifugal Pumps i2mo, 

The Fan i2mo, 

Isherwood, B. F. Engineering Precedents for Steam Machinery . . . 8vo, 
Ivatts, E. B. Railway Management at Stations 8vo, 

Jacob, A., and Gotdd, £. S. On the Designing and Construction of 

Storage Reservoirs. (Science Series No. 6) i6mo, o 50 

Jannettaz, E. Guide to the Determination of Rocks. Trans, by G. W. 

Pljrmpton i2mo, 

Jehl, F. Manufacture of Carbons. x 8vo, 

Jennings, A. S. Conunercial Paints and Painting. (Westminster Series.) 

8vo, 

Jennison, F. H. The Manufacture of Lake Pigments 8vo, 

Jepson, G. Cams and the Principles of their Construction 8vo, 

Mechanical Drawing 8vo (In Preparation.) 

Jervis-Smith, F. J. Dynamometers 8vo, 

Joddn, W. Arithmetic of the Gold and Silversmith iimo, 

Johnson, J. H. Arc Lamps and Accessory Apparatus. (Installation 

Manuals Series.) i2mo, 

Johnson, T. M. Ship Wiring and Fitting. (Installation Manuals Series.) 

i2mo, 

Johnson, W. McA. The Metallurgy of Nickel (/« Pre paraliou .) 

Johnston, J. F. W., and Cameron, C. Elements of Agricultural Chemistry 

and Geology i2mo, 

Joly, J. Radioactivity and Geology i2mo, 

Jones, H. C. Electrical Nature of Matter and Radioactivity i2mo, 

Evolution of Solutions ( /« Press. ) 

Now Era in Chemistry iimo, 

Jones, J. H. Tinplate Industry 8vo, 

Jones, M. W. Testmg Raw Materials Used in Paint 1 2mo, 

Jordan, L. C. Practical Railway Spiral i2mo, leather, 

Joynson, F. H. Designing and Construction of Machine Gearing . . 8vo, 
Jiiptner, H. F. V. Siderology : The Science of Iron 8vo, 

Kansas City Bridge 4to, 

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Keim, A. W. Prevention of Dampness in Buildings 8vo, 

Keller, S. S. Mathematics for Engineering Students. 1 2mo, half leather. 

Algebra and Trigonometry, with a Chapter on Vectors *i 

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and Knox, W. E. Analytical Geometry and Calculus *2 00 

Kelsey, W. R. Continuous-current Dynamos and Motors 8vo, 



I 


50 


*4 


00 


*2 


00 


*3 


00 


♦i 


50 


*3 


50 


*i 


00 


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75 


*o 


75 


2 


60 


'5 


00 


*2 


00 


*2 


GO 


*3 


GO 


*2 


00 


*I 


50 


2 


00 


*5 


00 


6 


00 





50 


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75 


*i 


25 


*2 


00 


♦2 


50 



l6 D. VAN NOSTRAND CO.'S SHORT TITLE CATALOG 

Eemble, W. T., and Underbill, C. R. The Periodic Law and the Hydrogen 

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Kemp, J. F. Handbook of Rocks Syo, *i 50 

Kendall, E. Twelve Figure Cipher Code 4to, *i2 50 

Kennedy, A. B. W., and Thurston, R. H. Kinematics of Machinery. 

(Science Series No. 54.) i6mo, o 50 

Kennedy, A. B. W., Unwin, W. C, and Idell, F. £. Compressed Air. 

(Science Series No. 106.) i6mo, 

Kennedy, R. Modem Engines and Power Generators. Six Volumes. 4to, 

Single Volumes each, 

Electrical Installations. Five Volumes 4to, 

Single Volumes each, 

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Principles of Aeroplane Construction 8vo, 

Kennelly, A. £. Electro-Dynamic Machinery 8vo, 

Kent, W. Strength of Materials. (Science Series No. 41.) i6mo, 

Kershaw, J. B. C. Fuel, Water and Gas Analysis 8vo, 

Electrometallurgy. (Westminster Series.) 8vo, 

The Electric Furnace in Iron and Steel Production i2mo, 

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Kindelan, J. Trackman's Helper x2mo, 

Kinzbrunner, C. Alternate Current Windings 8vo, 

Continuous Current Armatures 8vo, 

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Kirkham, J. E. Structural Engineering 8vo, 

Kirkwood, J. P. Filtration of River Waters 4to, 

Kirschke, A. Gas and Oil Engines i2mo, 

Klein, J. F. Design of a High-speed Steam-engine Svo, 

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Knight, R.-Adm. A. M. Modem Seamanship Svo, 

Half morocco *9 00 

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Knox, J. Physico-Chemical Calculations 1 2mo, 

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Cosmetics Svo, 

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E. Potts Svo, 

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Lallier, E. V. Elementary Manual of the Steam Engine i2mo, 2 00 

Lambert, T. Lead and Its Compoimds Svo, '3 50 

- Bone Products and Manures Svo, '3 '"O 






50 


15 


00 


3 


00 


15 


00 


3 


50 


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00 


*i 


50 


I 


50 





50 


*2 


50 


•2 


00 


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00 


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50 


•i 


50 


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50 


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00 


10 


00 


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50 


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50 


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00 


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3 


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50 


•9 


00 


2 


00 


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75 


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D. VAN NOSTRAXD CO.'S SHORT TITLE CATALOG 17 

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Lancaster, M. Electric Cooking, Heating and Cleaning 8vo, "^i 50 

Lanchester, F. W. Aerial Flight. Two Volumes. 8vo. 

Vol. I. Aerodynamics *6 00 

Aerial Flight. Vol. n. Aerodonetics *6 . 00 

Lange, K. R. By-Products of Coal-CTas Manufacture i2mo, 2 00 

Lamer, £. T. Principles of Alternating Currents lamo. ^i 25 

La Rue, B. F. Swing Bridges. (Science Series No. 107.) i6mo, o 50 

Lassar-Cohn. Dr. Modem Scientific Chemistry. Trans, by M. M. 

Pattison Muir iimo, *2 00 

Latimer, L. H., Field, C. J., and Howell, J. W. Incandescent Electric 

Lighting. (Science Series No. 57.) i6mo, o 50 

Latta, M. N. Handbook of American Gas-Engineering Practice . . . 8vo, *4 50 

American Producer Gas Practice 4to, *6 00 

Laws, B. C. Stability and Equilibrium of Floating Bodies 8vo, "^3 50 

Lawson, W. R. British Railways. A Financial and Commercial 

Survey 8vo, 200 

Leask, A. R. Breakdowns at Sea i imo, 2 00 

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Lecky, S. T. S. " Wrinkles " in Practical Navigation Svo, *8 00 

Le Doux, M. Ice-Making Machines. (Science Series No. 46.) . . i6mo, o 50 
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Trades Edition.) oblong 4to *2 00 

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Binns 4to, *7 50 

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Lemstrom, S. Electricity in Agriculture and Horticulture Svo, *i 50 

Letts, E. A. Fundamental Problems in Chemistry Svo, ^^2 00 

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Lewes, V. B. Liquid and Gaseous Fuels. (Westminster Series.) . .8vo, *2 00 

Carbonization of Coal Svo, *3 00 

Lewis, L. P. Railway Signal Engineering Svo, *3 50 

Lieber, B. F. Lieber's Standard Telegraphic Code Svo, *io 00 

Code. German Edition Svo, *io 00 

Spanish Edition Svo, *io 00 

French Edition Svo, *io 00 

Temunal Index Svo, *2 50 

Lieber's Appendix folio, *i5 00 

Handy Tables 4to, *2 50 

Bankers and Stockbrokers' Code and Merchants and Shippers' 

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100,000,000 Combination Code Svo, •lo 00 

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man 1 2mo, *i 00 

Livingstone, R. Design and Construction of Commutators Svo, *2 25 

Mechanical Design and Construction of Generators Svo, *3 50 

Lobben, P. Machinists' and Draftsmen's Handbook Svo, 2 50 



p 


j8 d- van nostrand co.'s short title catalog 


m 


p 




2 50 




Lockwood, T. D. Electrical Measuremenl and the Gal^-anometer, 






Lodge, O. J. Elemealaiy Mechanics umo, 


75 

1 S" 




— Signalling Across Space without Wires ... Svo, 






Loewensiein, L. C, and Crissey, C. P. Centrifugal Pumps 


*« 50 




LomaK, J. W. Cotton Spinning ._ iimo, 


I 50 




Lord, B. T. Decorative and Fancy Fabrics Svo, 


•3 so 
sn 








--—Handbook. (Science Series No. jg.) . 16111, 


o 5dO 




Lovell, D. H. Practical Switchwork iimo, 






Low, D. A. Applied Mechanics lElementaiyi i6ino, 


080 


L 


Lubschez, B. J. Perspective lamo, 


*i so 


■ 


Lucke, C. E. Gas Engine Design 8vo. 


'3 w 


I 


Power Plants: Design, Efficiency, and Power Costs, a wols. 




■ 


(/'I PrriMTation.) 






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•3 « 




Lunge, G. Coal-tar and Ammonia. Three Volumes , 


•iS 00 




Technical Gas Analysis 8vo, 


•400 


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■ 


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18 0* 


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w 


parts . . 


15 00 




Vol. in. Ammonia Soda 


'10 00 




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Technical Chemists' Handbook umo.leather. 


'3 so 




Technical Methods of Chemical Analysis. Trans, by C. A. Eeane 












Vol. I. In two parts , . Svo, 


19 00 




Vol. U. In two parts Svo. 


1800 




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IB 00 




The set (3 vols. ) complete 






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•i s* 




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Each volume separately 


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'» 50 




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•a 50 




Mackie, J. Ho* to Make a Woolen Mill Pay Sro, 






Mackrow, C. Naval Architect's and Shipbuilder's Pocket-book. 






i6mo, le«th«r. 


500. 




Maguire, Wm. B. Domestic Sanitaiy Drainage and Plumbing . .8ro, 


4 W» 




Malcolm, C. W. Tenlbook on Graphic Statics avo, 


■3 CM 




Malcolm, H. W. Submanne Telegraph Cable (/" /Vrw.) 






Mallet, A. Compound Engines. Trans, by B. B. Buel. (Science Series 






No. 10.) .i-imo. 






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50 




Harks, E, C. R. Construction of Cranes and Lifting Machinery iiiao. 


•1 50 




Construction and Working of Pumps i»mo, 


•t 50 


—A 


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50 



D. VAN NOSTRAND CO/S SHORT TITLE CATALOG 19 

Manufacture of Iron and Steel Tubes lamo, 

Mechanical Engpmeering Materials iimo, 

Marks, G. C. Hydraulic Power Engineering 8vo, 

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Mariow, T. G. Drying Machinery and Practice 8vo, 

Marsh, C. F. Concise Treatise on Reinforced Concrete 8vo, 

^— Reinforced Concrete Compression Member Diagram. Mounted on 

Cloth Boards ♦x .50 

Marsh, C. F., and Dunn, W. Manual of Reinforced Concrete and Con- 
crete Block Construction i6mo, morocco, ^2 50 

Marshall, W. J., and Sankey, H. R. Gas Engines. (Westminster Series.) 

8vo, *2 00 

Martin, G. Triumphs and Wonders of Modem Chemistry 8vo, *2 00 

Modem Chemistry and Its Wonders 8vo, *2 00 

Martin, N. Properties and Design of Reinforced Concrete i2mo, *2 50 

Martin, W. D. Hints to Engineers i2mo, *i 00 

Massie, W. W., and Underhill, C. R. Wireless Telegraphy and Telephony. 

i2mo, *i 00 
Matheson,D. Australian Saw-Miller's Log and Timber Ready Reckoner. 

i2mo, leather, i 50 

Mathot, R. E. Internal Combustion Engines 8vo, *6 00 

Maurice, W. Electric Blasting Apparatus and Explosives 8vo, *3 50 

Shot Firer's Guide 8vo, ^i 50 

Maxwell, J. C. Matter and Motion. (Science Series No. 36.). 

i6mc, o 50 
Maxwell, W. H., and Brown, J. T. Encyclopedia of Municipal and Sani- 
tary Engineering 4to, *io 00 

Mayer, A. M. Lecture Notes on Physics 8vo, 

Mayer, C, and Slippy, J. C. Telephone Line Constmction 8vo, 

McCullough, E. Practical Surveying iimo, 

Engineering Work in Cities and Towns 8vo, 

Reinforced Concrete i2mo. 



2 


00 


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3 


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McCullough, R. S. Mechanical Theory of Heat 8vo, 

McGibbon, W. C. Indicator Diagrams for Marine Engineers Svo, 

Marine Engineers' Drawing Book oblong 4to, 

Mcintosh, J. G. Technology of Sugar Svo, 

Industrial Alcohol Svo, 

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Svo. 

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Vol. II. Varnish Materials and Oil Varnish Making *4 00 

Vol. III. Spirit Varnishes and Materials *4 50 

McBLnight, J. D., and Brown, A. W. Marine Multitubular Boilers *i 50 

McMaster, J. B. Bridge and Timnel Centres. (Science Series No. 20.) 

i6mo, o 50 

McMechen, F. L. Tests for Ores, Minerals and Metals i2mo, "^i 00 

Mcpherson, J. A. Water-works Distribution Svo, 2 50 

Meade, R. K. Design and Equipment of Small Chemical Laboratories, 

Svo, 

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I 


00 


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20 D. VAN NOSTRAND CO.'S SHORT TITLE CATALOG 

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Merck, £. Chemical Reagents; Their Purity and Tests. Trans, by 

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Merritt, Wm. H. Field Testing for Gold and Silver i6mo, leather, 

Meyer, J. G. A., and Pecker, C. G. Mechanical Drawing and Machine 

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Mierzinski, S. Waterproofing of Fabrics. Trans, by A. Morris and H. 

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Milroy, M. £. W. Home Lace-making i2ma, 

Mitchell, C. A. Bftineral and Aerated Waters Syo, 

Mitchell, C. A., and Prideaux, R. M. Fibres Used in Textile and Allied 

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Mitchell, C. F., and G. A. Building Construction and Drawing. lamo. 

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Advanced Course *a 50 

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Monteverde, R. D. Vest Pocket Glossary of English-Spanish, Spanish- 
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Montgomery, J. H. Electric Wiring Specifications i6mo, *x 00 

Moore, E. C. S« New Tables for the Complete Solution of Ganguillet and 

Sutter's Formula 8vo, *5 00 

Morectoft, J. H., and Hehre, F. W. Short Course in Electrical Testing. 

8vo, 

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Moses, A. J. The Characters of Crystals 8vo, 

and Parsons, C. L. Elements of Mineralogy 8vo, 

Moss, S. A. Elements of Gas Engine Design. (Science Series No. 1 2 1 . ) 1 6mo, 

The Lay-out of Corliss Valve Gears. (Science Series No. 119. ) i6mo, 

Mulford, A. C. Boimdaries and Landmarks i2mo, 

Mullin, J. P. Modem Moulding and Pattern-making i2mo, 

Munby, A. E. Chemistry and Physics of Building Materials. (West- 
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Murphy, J. G. Practical Mining i6mo, 

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Sold separately, each, "^3 00 
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Naquet, A. Legal Chemistry i2mo, 

Nasmith, J. The Student's Cotton Spinning 8vo, 

Recent Cotton Mill Construction i2mo, 

Neave, G. B., and Heilbron, L M. Identification of Organic Compounds. 

i2mo, 

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Nerz, F. Searchlights. Trans, by C. Rodgers 8vo, •j 00 

Neuberger, H., and Noalhat, H. Technology of Petroleum. Trans, by 

J. G. Mcintosh 8vo, •lo 00 

Newall, J. W. Drawing, Sizing and Cutting Bevel-gears 8vo, i 50 



•l 


50 


•l 


50 


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50 





50 





50 


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D. VAN NOSTRAND CO.'S SHORT TITLE CATALOG 21 

Newbeging, T. Handbook for Gas Engineers and Managers 8vo, "^6 50 

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Nicol, G. Ship Construction and Calculations 8vo, *4 50 

Nififaer, F. £. Theory of Magnetic Measurements i2mo, i 00 

Kisbet, H. Grammar of Textile Design 8vo, *3 00 

Nolan, H. The Telescope. (Science Series No. 51.) i6mo, o 50 

Noll, A. How to Wire Buildings iimo, i 50 

North, H. B. Laboratory Experiments in General Chemistry lamo, *i 00 

Nugent, £. Treatise on Optics iimo, i 50 

O'Connor, H. The Gas Engineer's Pocketbook lamo, leather, 3 50 

Petrol Air Gas i2mo, *o 75 

Ohm, G. S., and Lockwood, T. D. Galvanic Circuit. Translated by 

'^niliam Francis. (Science Series No. 102.) i6mo, o 50 

Olsen, J. C. Text-book of Quantitative Chemical Analysis 8vo, *4 00 

Olsson, A. Motor Control, in Turret Turning and Gun Elevating. (U. S. 

Navy Electrical Series, No. i.) i2mo, paper, *o 50 

Ormsby, M. T. M. Surveying lamo, i 50 

Oudin, M. A. Standard Polyphase Apparatus and Systems. 8vo, *i 00 

Owen, D. Recent Physical Research 8vo, *i 50 

Pakes, W. C. C, and Nankivell, A. T. The Science of Hygiene . .8vo, *i 75 

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Parker, P. A. M. The Control of Water 8vo, *$ 00 

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I 



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24 D. VAN NOSTRAXD CO.'S SHORT TITLE CATALOG 

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Svo, ( /;; I'rcss.) 



*2 


00 


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75 
50 


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Sellew, W. H. Steel Rails 4to, *i2 50 

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First Year 

Second Year 

Third Year 

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Tod, J., and McGibbon, W. C. Marine Engineers* Board of Trade 

Examinations Svo. 






50 


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75 


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D. VAN NOSTRAND CO.'S SHORT TITLE CATALOG 29 

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