SILVER. 131 



of nitric and muriatic acid, which dissolves it; such 

 an acid contains free chlorine, for the oxygen of the 

 nitric acid takes the hydrogen of the muriatic acid, 

 and sets free the chlorine; hence, we learn that the 

 only solvent of gold is, in fact, a solution of chlorine. 



293. When a solution of chloride of gold, thus 

 ohtained, is mixed with a solution of potash or soda, 

 a dark-colored precipitate falls: this is an oxide of 

 gold; when heated, it parts with the oxygen which 

 it contains, and pure gold is left. The soluble com- 

 pounds of the metal gold are all very easily decom- 

 posed, because the metal has but a very feeble affinity 

 for oxygen, chlorine, &c. 



294. Silver, like gold, occurs native in its pure 

 metallic state, but it more commonly is found com- 

 bined with sulphur, as a sulphuret. It resembles gold 

 in having a feeble affinity, for oxygen, so that it does 

 not oxidize either at common temperatures, or when 

 heated, and most of its compounds are easily decom- 

 posed, the silver reassuming the metallic state. Sil- 

 ver readily dissolves in nitric or sulphuric acid, and 

 the solutions obtained yield oxide of silver, when 

 decomposed by an alkali; the oxide of silver is a 

 salifiable base, and combines with acids to form salts. 



295. The compounds of silver are nearly all de- 

 composed by mere exposure to light. So feeble is 

 the affinity which it has for most other substances, 

 that the greater number of its compounds are decom- 

 posed or reduced by mere exposure to sunshine. This 

 fact is interesting as an illustration of the chemical 



