482 



SCIENCE. 



[N. S. Vol. XXIV. No. 616. 



tion to us that he has braved the perils of 

 a long ocean voyage to honor us with his 

 presence at our celebration of the semi- 

 centennial of the coal tar industry, initi- 

 ated by the discovery of Perkin's mauve. 

 Only fifty years ago, while engaged in re- 

 search, having for its object the artificial 

 production of quinine, Perkin, then an 

 eighteen-year old assistant of Hofmann, ob- 

 tained a muddy, dark precipitate, from 

 which he first endeavored to extract cer- 

 tain colorless crystalline substances which 

 might adequately explain the reaction un- 

 der observation. One day, however, the 

 thought occurred to him to utilize this 

 colored precipitate itself for the dyeing of 

 silk. It is hard to realize to-day what an 

 epoch-making idea it was at that time to 

 dye fabrics with a substance evolved in the 

 laboratory and having no relation what- 

 ever to the dyestuffs then known. It was 

 truly the spark of genius which led Perkin 

 to investigate the dyeing properties of that 

 dark-colored precipitate which would have 

 been cast away by any other scientist of 

 that period and particularly by his master, 

 Hofmann, who objected to experimenting 

 with anything which did not crystallize 

 and who had at that time a strong aversion 

 to working with substances which were 

 colored. For the latter, when produced in 

 reactions, were generally regarded as sec- 

 ondary products and every endeavor was 

 made to get rid of them, so that the other 

 substances associated with them might be 

 examined. 



But however great the discovery of 

 mauve, and however much we must admire 

 the courage of the youth who undertook its 

 technical production, yet these steps were 

 only trivial incidents in the immense revo- 

 lution brought about by Perkin's genius. 

 The greatest obstacles encountered by him, 

 and the most difficult task to be performed, 

 was when he attempted to sell the color to 

 dyers and printers. At that time men of 



this class worked by the rule of thumb with 

 secret recipes, mostly inherited from their 

 forefathers, and their formula, although 

 applicable to natural colors, were not suit- 

 able for mauve. Thus Perkin and his 

 associates had to prepare new directions 

 for dyeing and printing and to induce 

 those ultra conservative dyers to adopt the 

 new methods. It has been almost for- 

 gotten that Perkin was the first to intro- 

 duce the method of dyeing silk in a soap 

 bath which is commonly employed to-day 

 for all artificial dyestuffs, and that he and 

 Pullar first made use of the mordanting 

 of cotton with the insoluble inorganic com- 

 pounds of tannin. 



Thus the introduction of mauve com- 

 pletely changed the art of dyeing and 

 printing, simplifying the processes and 

 substituting for the old time formulae 

 the scientific recipes furnished by the 

 color manufacturers of the present day. 

 After Perkin had thus removed the ob- 

 stacles in the path of practical application, 

 it became comparatively easy to introduce 

 other coal tar colors. 



But Perkin also paved the way for the 

 discovery of the later coal tar colors by 

 creating commercially aniline and benzole, 

 which up to his time had only been labora- 

 tory curiosities. Of the three methods 

 available for obtaining aniline he selected 

 as the most promising the reduction of 

 nitrobenzol, made by nitration of coal tar 

 benzol, and the production of aniline from 

 this source led, shortly after the discovery 

 of mauve, to the discovery of magenta, 

 which opened up a new and immense field 

 for this industry. Aniline from benzole 

 was later found to contain toluidine, which 

 is not present in aniline from indigo or 

 that obtained directly from coal tar, and 

 Perkin truly said in a lecture delivered 

 December 7, 1868 : 



Had the aniline contained in coal tar or the 

 aniline obtained from indigo been employed for 

 the preparation of mauve, instead of that pre- 



