58 Professor Boscoe on a New Chemical Industry. [Feb. 21, 



now known as iodine green, formed during the manufacture of the 

 violet, and produced from the latter colour by the action of methyl 

 iodide. 



In order to prepare aniline green from the pure chloride of 

 methyl, a solution of methyl-aniline violet in methyl alcohol is 

 placed in an iron digester and the liquid rendered alkaline by caustic 

 soda. Having closed the digester, a given quantity of liquid chloride 

 of methyl is introduced by opening a tap, and the digester thus charged 

 is placed in a water bath and heated by a jet of steam, until the 

 temperature reaches 95°, and the indicated pressure amounts to from 

 4 to 5 atmospheres. As soon as the reaction is complete, the hot 

 water is replaced by cold, and the internal pressure reduced by 

 opening the screw tap of the digester. The product of this reaction 

 heated and filtered, yields the soluble and colourless base, whose salts 

 are green. To the acidulated solution a zinc salt is added to form a 

 double salt, and the green compound is then x>recipitated by the 

 addition of common salt. By adding ammonia to a solution of the 

 green salt, a colourless liquid is obtained, in which cloth mordanted 

 with tannic acid and tartar emetic becomes dyed of a splendid green. 



If rosaniliue be substituted for methyl aniline in the preceding 

 reaction Hofmann's violet is obtained. The application of methyl 

 chloride to the preparation of violets and greens is, however, it must 

 be remembered, not due to M. Vincent; it has been practised for 

 some years by aniline-colour makers. M. Vincent's merit is in 

 establishing a cheap method by which perfectly pure chloride of 

 methyl can be obtained, and thus rendering the processes of the 

 manufacture of colours much more certain than they have been 

 hitherto. 



The production of methyl violet from di-methyl aniline, may be 

 easily shown by heating this body with a small quantity of chloral 

 hydrate, and then introducing some coj)per turnings into the hot 

 liquid. On pouring the mixture into alcohol, the violet colour is 

 well seen. 



In reviewing this new chemical industry of the beet-root vinasses, 

 one cannot help being struck by the knowledge and ability which 

 have been so successfully expended by M. Camille Vincent on the 

 working out of the processes. 



Here again we have another instance of the utilization of waste 

 chemical products and of the preparation on a large scale of com- 

 pounds hitherto known only as chemical rarities. 



All those interested in scientific research must congratulate 

 M. Camille Vincent on this most successful issue of his labours. 



[H. E. R.] 



