665 



I further extended this investigation to the three toluidines, and I 

 have succeeded in determining the limits of existence of tliree 

 compounds. I have determined tiie composition of two of these 

 compounds by analysis; the composition of the third had already 



P 



to 



50 



T 



Fig. i. 



been found by Ditte. Ttie great analogy between the three systems 

 Avill probably justify the conclusion that these compounds are the 

 three isomer tolyl carbaminic acids. 



2. The system aniline-carbonic acid; the phenyl carbaminic acid. 



From "anilin purissimum" of Merck coloured red by contact with 

 the air a middle fraction was separated by fractionation ; a slight quantity 

 of this was put into the Cailletet tube by the aid of a long glass capillary. 

 As a test tube I used a tube with a widened upper end of the same 

 shape as in my researches on the systems ether- water and hexane- water'). 

 For the tilling with carbonic acid the test tube was connected with 

 a ground piece to an apparatus consisting of a generating apparatus 

 for carbonic acid, which was obtained from diluted sulphuric acid 

 and sodium bicarbonate, and was dried with phosphorus pentoxide, 



1) These Proc. 15. 380 (1912/13), 



2) These Proc. 16. 404 (1213 14). 



