88 Proceedings of the Royal Irish Academy. 



by dissolving in hot dilute alcohol, and filtering while hot. On cooling, it 

 separated out, and was filtered and dried. It is a dark blue amorphous 

 powder, easily soluble in water to a purple red solution. The compound dyed 

 cotton directly a purple shade. 



•1837 substance gave 13"2 c.c. moist nitrogen at 11° C. and 756 mm. P., 

 corresponding to N = 8'52, 

 C3 2 H„N,Na t S,OH requires N = 873. 



2. Coup/in;/ "J J!iinidine-Sulphovx-Disulphonic Acid with fi-NapMhylamirie. 



NHi SOjNa SOaNa NII- 



I II l_ 



/ >_x = N _Q_Q_ K = N _/ \ 



A cold solution of 44 grams of |3-naphthylaniine in a mixture of 600 c.cs. 

 of water and 30 c.cs. concentrated hydrochloric acid was prepared, and into 

 this was poured the tetrazotised solution from 20'3 grams of benzidine- 

 sulphone-disulphonic acid. The mixture was stirred mechanically for two 

 days, and after the first half-hour's stirring a solution of ~>0 grams of sodium 

 carbonate was added slowly, so that the whole was added by the end of the 

 second day. After standing overnight, the colouring matter was heated to 

 iid the mixture saturated with common salt and cooled, when the 

 precipitated colouring matter was dried ami ground. It was purified from 

 dilute alcohol, from which it readily separated, and was dried at the pump. 

 I he pure substance i- .i reddish amorphous powder, which dissolves in water, 

 giving a deep-red solution. The substance dyed cotton directly a violet red. 



•1608 substance gave 146 c.cs. moisl nitrogen at 13° C. and 770 mm. P., 

 corresponding to N = 10 - 87, 

 1 .11. X,Na,S 3 0, requires X = 110. 



3. Coupling "/' BeTuridhic-SulphoTic-IH&iUphonic Acid with u-Naphthylamine. 



SOiNa Ml 



A- m the preceding pieparation, the tetrazotised product of 20-3 grams 

 benzidine-sulphone-disulphonic acid was poured into a cold solution of 

 44 grams a-naphthylamine in a mixture of 600 c.cs. of water, with 30 c.cs. 

 HC1, and the mixture stirred by means of a turbine for two days. After 



