THE GROWTH OF CHEMICAL IDEAS 123 



1845, Hofmann became professor of chemistry in the newly 

 founded Royal College of Science in London. One of his 

 students, W. H. Perkin, as a boy of seventeen discovered the 

 first synthetic dye. In 1864 Hofmann went to the University 

 of Berlin as professor of chemistry, and in his laboratory 

 were trained many of the chemists who established the Ger- 

 man dye industry. 



In the early days of organic synthesis, the structure of the 

 compounds produced was very difficult to understand. In 

 1835, Friedrich Wohler, then teaching at Cassel, wrote to 

 Berzelius, under whom he had studied: "Organic chemistry 

 just now is enough to drive one mad. It gives me the im- 

 pression of a primeval tropical forest, full of the most re- 

 markable things, a monstrous and boundless thicket, with no 

 way of escape, into which one may well dread to enter." 



We can easily understand this feeling of Wohler's. The 

 increase in the number of the compounds of carbon, which 

 have since shown such amazing proliferation, naturally ap- 

 palled chemists accustomed to think in terms of the simpler 

 inorganic chemistry. The difficulty, of course, was that 

 through the ''forest" of which Wohler wrote there w^as no 

 path blazed. No one had mapped a system of organic chem- 

 istry. The beginning of the making of this path was the 

 work of von Liebig and Wohler. Unlike as the two were, 

 von Liebig was justified when he wrote to Wohler: "When 

 we are dead, the bonds which united us in life will always 

 hold us together in the memory of men as a not frequent 

 example of two men who loyally, without envy or malice, 

 contended and strove in the same domain and yet remained 

 closely united in friendship." 



The key to the understanding of organic compounds came 

 wdth the idea that certain groups of atom^ are to be found in 

 many compounds of cognate structure. Thus, if ethyl alcohol 

 and ethyl chloride are analyzed and their compositions writ- 

 ten, they will be represented as C2 He O and C2 H5 CI. Their 

 relationship becomes much clearer if w^e wTite these formulae 

 as C2 H5 OH and C2 H5 CI, from which w^e see that they 



