620 



NA TURE 



\_April2^, 1887 



of important progress made here, as well as on the Continent, 

 in the development of the manufacture, and of our knowledge 

 of the constitution, of the parent colours. 



In the next period of six years (1868-74I another great 

 stride was made in the coal-tar colour industry, due to 

 important scientific researches carried out by two German 

 chemists, Graebe and Liebermann, which led them, in the first 

 place, to obtain an insight into the true nature of the colouring- 

 matter of one of the most important staple dye-stuffs, namely the 

 madder-root. They found that this colouring-matter which 

 chemists call aliznritie was related to an/in-aciiic, one of the 

 most important solid hydrocarbons formed in the distillation of 

 coal, a discovery which was speedily followed by the artificial 

 formation of the madder -dye, alizarine, from that con- 

 stituent of coal-tar. At first, this achievement of Graebe 

 and Liebermann was simply of high scientific interest; but Perkin, 

 and Graebe, and Liebermann, were not long in discovering 

 methods by which the conversion of anthracene into the madder - 

 dye could be accomplished on a large scale, and the manufacture of 

 alizarine was soon most actively pursued in this country, with 

 very momentous results, as regards the market value of the 

 madder root. The latter has long been most extensively cultiva- 

 ted in Holland, South Germany, France, Italy, Turkey, and 

 India, the consumption of madder in Great Britain having 

 attained to an annual value of as much as 1,000,000/. sterling. 

 Playfair pointed out in 1852 that important improvements had 

 lately been attained in the extraction of the red colour or 

 alizarine from the madder-root, but those results, most valuable 

 at the time of the first Great Exhibition, became insignificant 

 when once the dye was artificially manufactured from anthra- 

 cene ; the price paid for madder in i86g was from $(i. to 8r/. 

 per pound, but now the equivalent in artificial madder-dye, 

 or alizarine, of one pound of the root, can be obtained for 

 one-halfpenny. 



With the discovery of artificial alizarine the truly scientific era 

 of the coal-tar industry may be said to have commenced, most 

 of the commercially valuable dye-products, obtained since that 

 time, being the result of truly theoretical research by the logical 

 pursuit of definite well-understood reactions. The wealth of 

 discovery in this direction made during the last thirteen years is 

 a most tempting subject to pursue ; but I must content myself 

 with mentioning that one of the results was the production of 

 very permanent and brilliant scarlet and red dyes, the manufac- 

 ture of which has greatly reduced the market value of cochineal ; 

 that the careful study of the original coal-tar colours led to 

 their production in a state of great purity by new and beautifully 

 simple scientific methods ; and that even 'the well-known vege- 

 table colouring matter, indi^^o, one of the staple products of 

 India, now ranks among the colours synthetically obtained by 

 the systematic pursuit of scientific research, from compounds 

 which trace their origin to coal-tar. 



The rapid development of the industry has al'o not failed to 

 exercise a very important beneficial influenc ■ ipon other chemical 

 manufactures ; thus, the distillation of tar, which was a com- 

 paratively very crude process, when, at the period of the first 

 Exhibition, benzene, naphtha, dead-oil, and pitch were the only 

 products furnished by it, has become a really scientific operation, 

 involving the employment of comparatively complicated but 

 beautiful distilling apparatus for the separation of the numerous 

 products which serve as raw materials for the many distinct 

 families of dyes. Very strong sulphuric acid became an essential 

 chemical agent to the alizarine manufacturer, and, as a conse- 

 quence, the so-called anhydrous sulphuric acid, the remarkable 

 crystalline body which was for many years prepared only in 

 small quantities from green vitriol, is now made at a low price 

 upon a very large scale by a beautifully simple process worked 

 out in England. The alkali- and kindred chemical trades have 

 been very greatly benefited by the large consumption of caustic 

 soda, of chlorate of potash, and other materials used in the dye 

 manufactures, and the application of constructive talent, con- 

 bined with chemical knowledge, to the production of efficient 

 apparatus for carrying out on a stupendous scale the scientific 

 operations developed in the investigator's laboratory, has greatly 

 contributed to the creation of a distinct profession, that of the 

 chemical engineer. 



<Jne of the most beneficial results of the rapid development of 

 the coal-tar colour industry has been its influence upon the ancient 

 art of dyeing, which made but very slow adv.ance until the pro- 

 vision of the host of brilliant, readily-applicable colours com- 

 pletely revolutionised both it and the art of calico-printing. 



I venture to think that it will be interesting at this point to 

 quote some words of jirophecy included in Prof. Hofmann's 

 important " Report on the Chemical Section of the Exhibition 

 of 1862," and to inquire to what extent they have been verified. 

 In commenting upon one of the features of greatest novelty in 

 that world's show, the exhibition of the first dye-products derived 

 from coal-tar, he says : — 



" If coal be destined sooner or later to supersede, as the 

 primary source of colour, all the costly dye woods hitherto con- 

 sumed in the ornam-ntation of textile fabrics ; if this singular 

 chemical revolution, so far from being at all remote, is at this 

 moment in the very act and process of gradual acci:)mplishment ; 

 are we not on the eve of profound modifications in the commer- 

 cial relations between the great colour-consuming and colour- 

 producing regions of the globe ? There is fair reason to believe 

 it prob.able that, before the period of another decennial Exhi- 

 bition shall arrive, England will have learnt to depend, for the 

 materials of the colours she so largely employs, mainly, if not 

 wholly, on her own fossil stores. Indeed, to the chemical mind 

 it cannot be doubtful that in the coal beneath her feet lie wait- 

 ing to be drawn forth, even as the statue lies waiting in the 

 quarry, the fossil equivalents of the long series of costly dye- 

 materials for which she has hitherto remained the tributary of 

 foreign climes. Instead of disbursing her annual millions for 

 these substances, England will, beyond question, at no distant 

 day become herself the greatest colour-producing country in the 

 world ; nay, by the strangest of revolutions, she may ere long 

 send her coal-derived blues to indigo-growing India, her tar- 

 distilled crimson to cochineal-producing Mexico, and her fossil 

 substitutes for quercitron and safflower to China, Japan, and the 

 other countries whence these articles are now derived." 



So far as concerns the displacement of madder, cochineal, 

 quercitron, safilower, and other natural dye-materials from their 

 positions of command in the markets of England and the world, 

 Hofmann's predictions have been amply fulfilled, and it appeared 

 in the earlier days of the coal-tar colour industry as though he 

 would be an equally true prophet in regard to England becoming 

 herself the greatest colour- producing country in the world. But, 

 although Germany did little in the very early days of this indus- 

 try, beyond producing a few of the known colours in a 

 somewhat impure condition, many years did not elapse ere she 

 not only was our equal in regard to quality of the dyes pro- 

 duced, but, moreover, had outstripped us in the quantities 

 manufactured and in the additions made to the varieties of 

 valuable dyes sent into the market. So far back as 1878 the 

 value of the make of colours in England was less than one- 

 fourth that of Germany, and even Switzerland, which, in 

 competing with other countries industrially, is at great natural 

 disadvantages, was not far behind us, ranking equal to France 

 as producers. The superior position of Germany in reference 

 to this industry may be in a measure ascribable to some defects 

 in the operation of our Patent Laws and to questions of wages 

 and conditions of labour ; but the chief cause is to be found in 

 the thorough realisation, by the German manufacturer, of his 

 dependence for success and continual progress upon the active 

 prosecution of scientific research, in the high training received 

 by the chemists attached to the manufactories, and in the 

 intimate association, in every direction, of systematic scientific 

 investigation with technical work. 



The young chemists whom the German manufacturer attracts 

 to his works rank much higher than ours in the general scientific 

 training which is essential to the successful cultivation of the 

 habit of theoretical and experimental research, and in the conse- 

 quent power of pursuing original investigations of a high order. 

 Moreover, the research laboratory constitutes an integral part of 

 the German factory, and the results of the work carried on by 

 and under the eminent pr ifessors at the universities and technical 

 colleges are closely followed and studied in their possible bear- 

 ings upon the further development of the industry. 



The importance attached to high and well-organised technical 

 education in Germany is demonstrated not only by the munificent 

 way in which the scientific branches of the universities and the 

 technical colleges are established and maintained, but also by 

 the continuity which exists between the different grades of educa- 

 tion ; a continuity, the lack of which in England was recently 

 indicated by Prof. Huxley with great force. 



The important part taken by the German universities in the 

 training of young men for technical pursuits has often been dwelt 

 upon as constituting a striking feature of contrast to our univer 

 sity systems. The national appreciation of the opportunities then- 



