1879. 1 



OH a New Chctnical Iitdiustyi/. 



67 



etlier, and sulpliuroiis acitl, freezing maebincs now in use, as they can 

 be sinij)ly constructed, and as tlie vapour and liquid do not attack 

 metal and are non-poisonous, and as the frigorific effects which it 

 is capable of producing are most energetic. 



The second and perhaps more important application of methyl 

 chloride is to the manufacture of metliylated colours. 



It is well known that rosaniline or aniline-red, C2oHigN3, yields 

 compounds possessing a fine blue, violet, or green colour, when a 



portion of the hydrogen has been replaced by the radicals methyl or 

 ethyl, and the larger the proportion of hydrogen replaced the deeper 

 is the shade of violet which is produced. Thus we have triethyl 

 rosaniline or Hofmann's * violet, C.^oHiBCCJoHjI-jNg. 



By rei^lacing one or two atoms of the hydrogen of aniline by 

 methyl and by oxidizinc? the methyl anilines thus obtained, Charles 

 Lauth obtained fine violet colours, whilst about the same time 

 Hofmann observed the production of a bright green colouring matter, 



* Hofmann, True. Roy. Soc' xiii. 13 (18G3). 



