10 [March 6, 



ammonium. A salt of rosaniline, when digested for some time with 

 sulphide of ammonium, furnishes a yellow, half-fused, scarcely cry- 

 stalline, brittle compound, which constitutes the leucaniline in a state 

 approaching purity. It is, however, by no means necessary to 

 employ for the preparation of this compound a rosaniline-salt in 

 the pure state. In most cases I have produced the leucaniline from 

 the commercial article sold under the name of fuchsine or magenta. 



To purify the product thus obtained, the yellow resinous mass is 

 powdered, washed with water to remove the sulphide of ammonium, 

 and dissolved in dilute hydrochloric acid, when sulphur, together 

 with impurities, are left behind. The dark-brown solution thus 

 obtained yields, with concentrated hydrochloric acid, a copious cry- 

 stalline precipitate, which, according to the degree of purity of the 

 commercial colouring matter, is either brown or yellow. Washing 

 with concentrated hydrochloric acid, in which the precipitate is in- 

 soluble, effects a considerable purification ; but in most cases it is 

 necessary to repeat the process of dissolving in dilute and reprecipi- 

 tating by concentrated hydrochloric acid once or twice. If the 

 solution, before the last addition of concentrated acid, be heated to 

 ebullition, the liquid remains clear, and the new chloride crystallizes 

 out only on cooling. The crystals are beautiful, white, rectangular 

 plates, which are, however, always very small. Recrystallization from 

 water, in which they are extremely soluble, renders them perfectly 

 pure. Or they may be dissolved in alcohol and precipitated by ether, 

 in which they are quite insoluble. 



The chloride thus purified yields, on addition of ammonia, the 

 leucaniline as a dazzling white powder, which assumes the faintest 

 rosy tint when left for some time in contact with the atmosphere of 

 the laboratory. It is scarcely soluble in cold, very little soluble in 

 boiling water, from which it is deposited, on cooling, in the form of 

 small crystals. It is very soluble in alcohol, and, although less so, 

 in ether. I have not been able to get it in good crystals from these 

 solvents. The best solvent appears to be a solution of the chloride 

 above described, in which leucaniline is freely soluble, and from 

 which, on cooling, it is deposited in the form of interlaced needles, 

 which are frequently united to spherical aggregations. Leucaniline 

 may be dried in vacuo over sulphuric acid without changing its 

 colour, When slightly heated it becomes red, and at 100 it fuses 



