552 Royal Society : — 



The water may be expelled at a higher heat ; but the temperatures 

 at which the water is lost and the salt commences to be decomposed 

 are so close to each other, that it is not quite easy to obtain the salt 

 in the anhydrous state. I have not been able to procure an oxalate 

 with a larger amount of acid. 



Acetate of Rosaniline. — This is probably the finest salt of the series. 

 Mr. Nicholson has obtained it in crystals an inch in diameter, which, 

 on analysis, were found to be the pure monacid acetate, viz., 



C 20 H 19 N 3 , II C 2 H 3 2 . 



The acetate is one of the more soluble salts, both in water and in 

 alcohol ; it cannot be conveniently recrystallized. 



The Formiate of Rosaniline is similar to the acetate. 



Of the remainder of the salts of this base I may mention the Chro- 

 mate, which is obtained by adding chromate of potassium to the solu- 

 tion of the acetate in the form of a brick-red precipitate, becoming a 

 green, crystalline, almost insoluble powder on ebullition with water. 



The Trinitrophenate also deserves to be noticed ; it crystallizes in 

 beautiful reddish needles, likewise very difficultly soluble in water, 

 which contain 



C 26 H 22 N 6 O 7 =C 20 H 19 N 3 , H C 6 H 2 (N0 2 ) 3 0. 



Multiplied and varied though the analytical results may be which, 

 support the formulae of rosaniline and its compounds, it appeared 

 desirable to seek additional experimental evidence for the expres- 

 sions derived from simple analysis. With this view I have studied 

 the products of decomposition of rosaniline. They are both 

 numerous and interesting. I must limit myself to-day to quote one 

 or two compounds which claim some attention, not only because they 

 unmistakeably confirm the formula which I have proposed, but also 

 on account of the light which they throw upon the nature of the 

 class of substances to which rosaniline belongs. 



Action of reducing agents upon Rosaniline, — This action appeared 

 to promise the simplest mode of controlling the formula of the new 

 base. My anticipations have not been disappointed. Rosaniline is 

 readily attacked by nascent hydrogen or sulphuretted hydrogen. A 

 solution of the base in hydrochloric acid, when left in contact with 

 metallic zinc, is rapidly decolorized. The liquid thus produced con- 

 tains, together with chloride of zinc, the hydrochlorate of a new tri- 

 amine, which, perfectly colourless as it is in the free state and in its 

 saline compounds, I propose to designate by the term Leucaniline. 

 The separation of the new compound from the zinc being tedious 

 and troublesome, I prefer to prepare it by the action of sulphide of 

 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, 



