416 AUGUST WILHELM VON HOFMANN. 



as many, or even more, papers were published by his students 

 under their own names, and these in most cases were as much 

 his work, except so far as mere manual labor was concerned, as 

 those included in the number given above. 



A general direction was given to Hofmann's work by his first 

 research in Liebig's laboratory, which consisted in proving the 

 identity of three substances, — benzidam from nitrobenzol, and 

 aniline and krystalline obtained in different ways from indigo. 

 He also showed that this substance (aniline) was contained in 

 the mixture of bases extracted from coal tar by Eunge, and 

 called by him kyanol. This called his attention to the com- 

 pounds of nitrogen, and in this class of bodies his most important 

 discoveries have been made. First among these must be placed 

 his work upon the aniline dyes, on account of the great industry 

 to which it has given birth; for although he had many competi- 

 tors in this field, and was not the first to introduce an aniline 

 color into commerce, his discoveries are so fundamental and 

 various that he can be justly called the father of this industry. 

 This work grew naturally from his first research just mentioned, 

 since rosaniline, the most important of these dyes, is easily 

 made by the oxidation of crude aniline. This substance was 

 first satisfactorily investigated by him, although it had been 

 obtained earlier by others, and he brought our knowledge of it 

 into such a state that it could be manufactured on a commercial 

 scale. From this rosaniline (magenta dye) he soon showed that 

 different colors could be obtained by replacing part of its hydro- 

 gen by other radicals ; and in this way he made violets and blues 

 of a brilliancy unknown before, which, with a vivid green that 

 soon followed, at once came into general use. It may be added, 

 that an investigation made under his direction laid the founda- 

 tions for preparing aniline itself on an industrial scale. This 

 work dates from his London period, and some idea of the excite- 

 ment of that time can be gained from the fact that he reported 

 the results of his analysis of aniline blue to the French Academy 

 by telegraph, probably the only time that a paper has been com- 

 municated in this way. 



■ Another discovery of his, although not yet of technical value, 

 is even more important to chemists than the work just men- 

 tioned. This is the method of preparing the amines by the 

 action of ammonia on alkyliodides or bromides, which alone 

 would have been sufficient to make him great, as by it not only 



