COLORATION OF ANILINE: II. 



429 



aniline distilling from the flask 6 were not allowed to condense in the tube d. 

 The middle fraction was sealed in the tube d in vacuo. 



S c a I <l : I = 2 



Drawn 4/ MeiHa 



I 



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Fig. 1. 



Both of these tubes were placed in the sun upon a white porcelain 

 plate, one on June 9 and the other on June 15, 1909. Since they both 

 behaved in exactly the same manner and the same experiments were 

 performed on each with the same results, one description will suffice 

 for both. 



Coloration of the aniline commenced at once in the sunlight and was 

 of a light yellow hue- in a few minutes, intensifying with the time to a 

 brilliant, dark red. At the time of opening the tubes, one on August 3, 

 1909, and one on August 9, after fifty- five days, the color was a very dark 

 red of such great intensity that a layer 0.25 centimeter thick appeared 

 black either by transmitted or reflected light. Very thin layers were a 

 deep brilliant red. 



The points of the tubes were broken under mercury in order to test the 

 vacuum. The mercury rose into the tube completely filling the vacant 

 space and showing no trace of gases. 



Small portions of the aniline were placed in small crystallizing dishes 

 in a vacuum desiccator over sulphuric acid. In about one week beautiful 

 crystals of azophenine began to separate. The large crystals measured 

 0.18 millimeter and the characteristic twins formed in large numbers. 

 Continued crystallization until the mass was solid failed to reveal the 

 presence of any solid other than azophenine. I do not think that any 

 other solid was present, except perhaps in the most minute traces, for 

 the perfect azophenine crystals continued to separate so long as any liquid 

 was present. 



Tests for ammonia gave positive results. N/o tests were made for 

 benzene. 



