750 The Outline of Science 



literally thousands of dyes of all hues and shades. The history 

 is very interesting, and it is briefly this. After some pioneer dis- 

 coveries, a big step was taken by Hofmann, a student in Liebig's 

 laboratory, who showed that brilliant colours could be obtained 

 from certain coal-tar products chemically related to an aniline 

 oil, which had been obtained long before by Zinin from natural 

 indigo. Hofmann went to teach in the Royal College of Science 

 in London, and he had as one of his students a boy of fifteen, 

 William Henry Perkin. This genius was set to work to prepare 

 artificial quinine, and in 1856 he discovered "mauve," the first 

 of the aniline dyes, and a new substance in the world. Ten years 

 later, he discovered how to produce artificially the colouring mat- 

 ter called "Turkey Red" or alizarin, which had previously been 

 obtained from the root of the madder plant. At one time half 

 a million tons of madder were raised annually in France, but 

 after Perkin's discovery, as Professor Slosson puts it, "the mad- 

 der fields of France were put to other uses, and even the French 

 soldiers became dependent on made-in-Germany dyes for their 

 red trousers. The British soldiers were placed in a similar situa- 

 tion as regards their red coats, when after 1878 the azo scarlets 

 put the cochineal bug out of business." For it was from the 

 body of the female cochineal insect (Coccus cacti), a native of 

 Mexico to start with, that the scarlet colouring matter was 

 obtained. 



We must not linger over the story of the coal-tar colours- 

 there are so many other creations to be discussed. What happened 

 in regard to "Turkey Red" happened in regard to indigo, which 

 came originally from an Indian plant, related to the British woad; 

 in regard to Tyrian Purple, which came originally from a Medi- 

 terranean sea-snail (Murex) ; and so in many other cases. It is 

 a matter for regret that when Hofmann returned to Germany 

 he practically took the young industry with him an instance of 

 British lack of imagination and foresight. "By 1914 the Ger- 

 mans were manufacturing more than three-fourths of all the 



