200 Proceedings of the Royal Irish Academy. 



was freed from a small amount of higher nitro compounds by boiling with 

 dilute alkali, and filtering. It melted, but not sharply, at about 135° C. : and 

 although on analysis it had a composition corresponding to that of a trinitro- 

 diphenylaniine, its further examination showed that it was a mixture of poly- 

 nitro-diphenylamines. Thus, ou exhausting it with hot carbon tetrachloride, 

 a small proportion of the substance dissolved, and after evaporation of the 

 solution and recrystallization from acetone-alcohol, a mixture of orange and 

 yellow crystals was got. The yellow crystals, when mechanically separated 

 from the orange, melted at 210 C. (uncorr.), and consisted of i'lO-dinitro- 

 dipkmylamine. The orange crystals which melted, but not sharply, about 

 195° ('. were not identified. 



The dark-brown resinous solid, which separated during the prolonged 

 Btanding of the diphenylamine and nitric acid in the acetic acid solutions, 

 was in. uly insoluble in all the ordinary solvents. It was not distinctly 

 crystalline, and did not melt below 280 C C. It is uot identical with any of 

 the known nitro derivatives of diphenylamine, and it' is probable that the red 

 'colour finally acquired by the acetic acid solution in the above experiments is 

 due t" trace.-, of this compound remaining in the solution. 



A determination of nitrogen in tins substance gave the following 



nits : — 



01 . i substance gave 19e.es nitrogen at 16° C. and 



767*4mma., corresponding to N 12*25. 



The low percentage of nitrogen in this substance indicates that in its 

 formation from diphenylamine- reactions other than nitration must have 

 occui 



B. — A ■■■ f A A don Diphenylnitro&imvne. 



7. To a solution of '-' grams of diphenylnitrosamine in L00c.cs of glacial 

 acetic acid 0*6c.ca of nitric acid (sp.gr. \'A'A) was added, and the mixture 

 was allowed to remain in a stoppered Uaak at the temperature of the 

 laboratorj for three weeks. The solution, which had an orange colour at the 

 end of the ip orange on the Becond, and retained this 



colour without separation of any solid until the twenty-firet day. when it was 

 pou l^d into excess of water. The orange precipitate thus got was filtered, 

 washed, and dried on a plate. The crude solid, which melted on the water* 

 bath, an i deep violet colouration with concentrated sulphuric acid; 



was obviously a mixture ol ^-nilro-diplienj/lnilrosamim and 2-nUrO'diphenyl- 

 nii !■ dlizing it from chloroform and alcohol we obtained 



the 4-nitTO'diphenylnitrosamine in a pure state. It consisted of nearlj 



