Dr. Schunck on Rubian and its Products of Decomposition. 271 



colour, consisting of small crystalline needles. It has no per- 

 ceptible taste at first, but on chewing it for some time it pro- 

 duces a slightly bitter taste. When heated on platinum it melts 

 and burns with a smoky flame slightly tinged with green, and 

 leaves a considerable quantity of charcoal. On being heated in 

 a tube it melts to a brown liquid, and gives fumes which condense 

 on the colder parts of the tube to a white crystalline sublimate, 

 consisting of star-shaped masses, while much carbonaceous resi- 

 due is left. On being treated with boiling water chlororubian 

 dissolves in considerable quantity, forming a yellow solution, 

 which on cooling deposits a great part of the substance, not in 

 crystals, but in amorphous masses consisting of spherical grains. 

 The boiling alcoholic solution, if very concentrated, also deposits 

 part of the substance on cooling in amorphous, spherical, trans- 

 lucent grains, which have the appearance of drops of oil, but by 

 redissolving these in fresh alcohol, crystals of the usual appear- 

 ance are obtained. The alcoholic solution does not redden litmus 

 paper in the least. The watery solution gives no precipitate with 

 nitrate of silver, but if chlororubian be treated with boiling nitric 

 acid, it is decomposed with an evolution of nitrous acid, forming 

 a colourless solution, in which nitrate of silver produces a pre- 

 cipitate of chloride of silver. The action of sulphuric and muri- 

 atic acids, caustic alkalies and chlorine on chlororubian, I shall 

 treat of presently. Chlororubian dissolves in boiling solutions 

 of the carbonates of potash, soda and ammonia, forming blood- 

 red solutions, which deposit nothing on cooling. Baryta water 

 imparts to the watery solution a deep red colour, and on boiling 

 dark red flocks are deposited, while the liquid becomes almost 

 colourless. Lime water turns the watery solution red without 

 producing any precipitate, but the ammoniacal solution gives 

 with chloride of calcium a light red flocculent precipitate, while 

 the supernatant liquid becomes colourless. The watery solution 

 gives no precipitate with the acetates of alumina and peroxide 

 of iron. On being treated with a boiling solution of perchloride 

 of iron, chlororubian dissolves with a brownish-yellow colour, 

 which after some time becomes dark brown, while a black powder 

 is deposited. The alcoholic solution of chlororubian does not 

 change on being mixed with an alcoholic solution of acetate of 

 lead, but the watery solution gives with basic acetate of lead a 

 light red precipitate, the liquid retaining a reddish colour. The 

 alcoholic solution gives no precipitate with acetate of copper. 

 An alkaline solution of chlororubian reduces chloride of gold to 

 the metallic state, even in the cold. Chlororubian produces no 

 eff'ect on mordants, on trying to dye with it in the usual manner. 

 On submitting chlororubian to analysis the following results 

 were obtained : — . , . 



