C hap. 3 5 .] Aftiw of Ether on a Solution of Gold. 235 



one hand, and the azote for hydrogen on the other, 

 are fcarcely fufficient to counteract. Whenever the 

 balance of power among thefe ingredients is difturbed, 

 which happens from a moderate increafe of heat, or 

 violent friction, the hydrogen and oxygen unite and 

 form water, the gold is reduced, and the azote efcapes 

 in the form of gas, occafioning a violent explofion. 



When gold is newly precipitated, Margraff informs 

 us, that it may be re-diffolved by the volatile alkali, 

 or, much more readily, by the PrufBan alkali. Alka- 

 line faits precipitate gold in the form of a calx, but 

 inflammable fubftances precipitate it in the metallic 

 form. The moft finguiar effect of inflammable fub- 

 itances upon the folution of gold is that of the vitriolic 

 ether, though it does not entirely feparate the gold 

 from the acid. If into a phial of diftilled water a fingle 

 drop of the folution of gold is introduced, the water 

 wil 1 * become of a fine yellow cotour; add to this a 

 quantity of vitriolic ether, which will float uppermoft, 

 and remain, colourlefs, no fenfible change being pro- 

 duced ; by fhaking the mixture, however, for fome 

 time, and then allowing it to reft, the yellow colour in 

 the loweft part of the phial will leave the water, and 

 rife up into the ether. By repeated agitation, in a 

 little time the ether will draw up into k the whole of 

 the gold, fo as to leave the liquor at bottom perfectly 

 colourlets. It would be erroneous to conclude from 

 this experiment, that ether is a folvent of gold; it does 

 not difiblve it, but attracts the folution merely by its 

 affinity for acids. Though, the ether acts primarily 

 on the acid, it at length feparates the oxygen from the 

 calcined gold, and precipitates it in its metallic ftate. 

 All the fubtile aromatic oils have a fimilar effect, but 

 do not act fo readily as ether. 



As thefe inflammable fluids have no action on the 

 4 folutions 



