INERT O Tele 
529 
THURSDAY, APRIL 7, 1904. 
COLOURING MATTERS, ARTIFICIAL AND 
NATURAL. 
A Systematic Survey of the Organic Colouring 
Matters. Founded on the German of Drs. G. 
Schultz and P. Julius. By Arthur G. Green, F.I.C., 
&c., Professor of Tinctorial Chemistry at the York- 
shire College, Leeds. Second edition. Pp. x+280. 
(London: Macmillan and Co., Ltd., 1904.) Price 
21s, net. 
A. PART from its special value to experts as a 
standard work of reference, the present com- 
pilation is of general interest as enabling chemists to 
gauge the progress in a department of industry which 
is perhaps more intimately associated with scientific 
research than any branch of manufacture that has been 
called into existence as the result of laboratory work. 
The first English edition bears the date 1894, and it 
was noticed in these columns at the time of its appear- 
ance (vol. 1. p. 267). The present edition, therefore, 
enables us to measure the development which has taken 
place during the last decade. First, with respect to 
the actual number of coal-tar colouring matters on the 
market. The edition of 1894 enumerated 454 distinct 
compounds; the present edition comprises 695; an 
apparent addition of 241 definite organic products of 
tinctorial value in ten years is an instructive illustration 
of the resources of chemical science when these are 
requisitioned in the service of industry. The actual 
number of new products is, however, even greater than 
this, since 59 dyestuffs which were included in the 
last edition have been removed from the list as being 
obsolete. The total number of new colouring matters 
is thus 300, so that the increment has been taking place 
at the rate of 30 per annum. 
A more detailed analysis of the tables will also serve 
to bring out the new departures which have been made, 
and which are, in part at least, responsible for the 
large number of new products added to the list. Thus 
in 1894 artificial indigo was entered as ‘‘ not in com- 
merce,’’ although the fundamental process which has 
since been developed with such marked success in 
Germany was known at that time, and the references 
to Heumann’s paper and the first patents of the 
Badische Company are included in the literature. In 
the present edition five processes for preparing synthetic 
indigo are tabulated, and five new products derived 
from or related to indigo are added to the tables as the 
outcome of the industrial development of the chemistry 
of this group of colouring matters. 
In the great domain of the azo-colours, the develop- 
ment is quite astonishing. From 234 recorded in the 
last edition, the number has now reached 383, grouped 
into 125 monazo, 203 disazo, 45 trisazo, and io tetra- 
kisazo compounds. The first representative of the 
group of colouring matters now known as_ the 
oxazines was discovered by the writer of this notice 
in 1879. In 1894 thirteen compounds belonging to 
this group were recorded as technical products; in the 
present edition 31 oxazines are in the tables. The 
NO. 1797, VOL. 69] 
first member of the sulphur-containing compounds, 
known as the thiazol or thiobenzenyl colouring matters, 
was discovered and introduced into commerce in 1887 
by Prof. Green under the name of ‘‘ primuline.’? The 
monopoly conferred by the right of discovery of this 
important compound was lost to the firm in the labor- 
atory of which the discovery was made by the adoption 
of the short-sighted policy that a new product could be 
protected as a ‘‘ trade secret.’’ Within a year of its 
introduction the Germans had found out its chemical 
constitution and were manufacturing it, and a German 
firm actually obtained patents for producing it in this 
country as well as in Germany. Those who are now 
bidding for notoriety by directing public attention to 
the ways in which British industries have been lost 
may draw some very instructive conclusions from the 
consideration of this little chapter in the history of 
industrial chemistry. 
Another very striking development, familiar, of 
course, to tinctorial chemists, and brought out con- 
spicuously by a comparison of the two editions of the 
present work, is to be found in the group of sulphide 
colouring matters. In 1873 the French manufacturers 
introduced under the name of ‘‘ Cachou de Laval”? a 
brown dyestuff prepared by fusing sawdust, bran, &c., 
with sodium sulphide. This figures in the 1894 edition 
as the only compound of its class. The action of fused 
sulphides upon definite organic compounds of known 
constitution has led since 1894 to the introduction of 
no less than 20 new colouring matters, into the com- 
position of which sulphur enters as an integral con- 
stituent of the molecule. Some of these compounds 
are black dyestuffs of great value on account of their 
fastness. They are, moreover, of particular scientific 
interest as offering a new field of research in connection 
with the question of the constitution of what may 
perhaps prove to be thiocyclic compounds. With the 
exception of the ‘‘immedial sky blue’? of Messrs. 
Cassella and Co., for which a probable formula is 
given, not one of these new compounds has even an 
empirical formula assigned to it. We have here, in 
fact, another illustration of the well-known principle 
that technology is often in advance of pure science. 
In many other directions can the industrial and 
scientific development of this great branch of chemical 
technology be traced in the pages of the present work. 
The raw and intermediate products of which the trans- 
lator and editor gave an account in the English edition 
numbered about 243 and occupied fifty-seven pages of 
the first edition. In the present edition some 60 new 
intermediate products have been introduced, and their 
description extends to more than seventy pages. 
Neither must the theoretical developments be over- 
looked in connection with an industry which is so 
intimately associated with the advancement of our 
knowledge of the chemical constitution of organic com- 
pounds. Evidence of this advancement is to be found 
throughout the tables before us, one of the results 
being a more detailed and perfect classification of the 
groups of colouring matters and the transference of 
many compounds of which the constitution was 
formerly unknown to definite places under their group 
type. It is of interest to note also in passing that the 
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