Pelletier m Gold, 119 



num, as M. Vauquelin has observed. The precipitates obtained 

 by the salts of silver are, according to M. Pelletier, mixtures of 

 the chloride of silver and oxide of gold. 



Action of soluble and insoluble salifiable Bases on the Chloride of 



Gold. 



This part of M. Pelletier's researches is the most interesting, 

 both for the difficulties which occurred, and the new results 

 obtained. The author commenced with the action of potash 

 on the per-chloride of gold, and the detail on this subject pre- 

 sents the key to all the pheienomena dependent on the action of 

 alcaline oxides, on the solution of the per-chloride of gold. The 

 potash acts differently according as it is added in excess or in 

 deficiency to the chloride. In the last case it does not imme- 

 diately cause a precipitate, but the liquor becomes of a deep red 

 colour, and at the end of some hours a precipitate appears, 

 which, however, may be produced immediately by heating the 

 liquor to ebullition. This precipitate recently prepared is of a 

 lemon yellow colour and gelatinous consistency. Frequent 

 washings with warm water separate the chlorides of gold and 

 potassium, which it at firist retains among its particles. It has 

 been considered by M. Oberkamp as a sub-muriate of gold, but 

 M. Pelletier having convinced himself that the muriatic acid in 

 it was not essential, joins in the opinion held by M. Vauquelin, 

 that it is an oxide of gold. 



This oxide exposed to the air dries and loses its lemon co- 

 lour, becoming blackish brown. In this way it loses the water, 

 which as a hydrate it held in combination, but is still perfectly 

 soluble in muriatic acid. If it be dried at the heat of boiling 

 water, one part of the oxide is reduced to the metallic state, 

 and only the portion not reduced will then dissolve in muriatic 

 acid. 



The fluid from which a part of the oxide of gold has been 

 precipitated by the addition of a portion insufficient for the 

 complete saturation of the chloride, remains of a yellow co- 

 lour, and is a mixture of the chlorides of gold and potassium. 



If instead of employing the potash as above, it be added in 



