CHLORIDE OF SILVER. 669 



Chloride of silver, Ag Cl, 1794.3 or 143.79. This salt, con- 

 tains in 100 parts, 24.67 parts of chlorine, and 75.33 parts of 

 silver. It is thrown down as a white precipitate, at first very 

 bulky and curdy, when hydrochloric acid or a soluble chloride 

 is added to any soluble salt of silver, except the hyposulphite. 

 It is wholly insoluble in water, and the most minute quantity of 

 hydrochloric acid contained in water may be detected by add- 

 ing to it a drop of a solution of nitrate of silver. Hydrochlo- 

 ric acid, when concentrated, dissolves chloride of silver, which 

 crystallizes from it in octohedrons, when the solution is evapo- 

 rated. This salt dissolves easily in solution of ammonia, and 

 crystallizes also as the ammonia evaporates. When heated, it 

 fuses about 500, forming a transparent yellowish liquid, which 

 becomes, after cooling, a mass that may be cut with a knife and 

 has considerable resemblance to horn ; a property to which it 

 was indebted for the name of horn silver, applied to it by 

 the elder chemists. It is not volatile. Chloride of silver is 

 not affected by a concentrated solution of potash. It is easily 

 reduced to the state of metal by zinc or iron with water. 

 Chloride of silver can be dissolved out in this way by means of 

 zinc and acidulated water, from a porcelain crucible, in which it 

 has been fused. The chloride and other salts of silver acquire 

 a dark colour when exposed to light ; chlorine escapes, and a 

 portion of the salt appears to be reduced to the metallic state, 

 as the blackened surface conducts electricity. According to 

 Wetzlar, the black substance contains an inferior chloride of 

 silver, and is not attacked by nitric acid, nor soluble in am- 

 monia. Indeed, paper charged with chloride of silver is ex- 

 ceedingly sensitive to the impression of light, and has been 

 employed to fix the image in the camera obscura. The unal- 

 tered chloride of silver in the paper, is afterwards dissolved 

 out by a solution of hyposulphite of soda. Of anhydrous 

 chloride of silver, 100 parts absorb I/. 9 1 parts of ammoniacal 

 gas, forming the compound 2Ag Cl-r3NH 3 . This compound 

 loses its ammonia in the air. Chloride of silver is dissolved by 

 concentrated and boiling solutions of chlorides of potassium, 

 sodium and ammonium, and, on cooling, a double salt is depo- 

 sited in crystals generally cubes. Chloride of silver is also 

 dissolved by cyanide of potassium, and the solution yields a 

 double salt by evaporation, (Liebig). 



Bromide of silver, Ag Br. 2330 or 186.7- This salt consists 



