92 An Inquiry concerning the 



I also revived the oxides of gold and of silver with 

 oil of olives by a similar process, with the heat of boil- 

 ing water. The oil of olives used in these experiments 

 lost its transparency, and became deeply coloured ; 

 that used in the reduction of the oxide of silver taking 

 a very deep dirty brown colour approaching to black, 

 and that employed in reducing the oxide of gold being 

 changed to a yellowish brown with a purple hue. 



In the experiment with the oxide of silver, the inside 

 of the phial in the region where the oil reposed on the 

 aqueous solution was beautifully silvered, the revived 

 metal forming a narrow metallic ring extending quite 

 round the phial ; and in both experiments small de- 

 tached pellicles of revived metal were visible in the oil, 

 and adhered in several places to the inside of the phial, 

 forming bright spots, in which the colour of the metal 

 and its peculiar splendour were perfectly conspicuous. 



Experiment No. 15. As carbon is one of the con- 

 stituent principles of spirit of wine, as well as of essen- 

 tial oils and sulphuric ether, I thought it possible that 

 I might succeed in the reduction of the oxide of gold, 

 by mixing alcohol with an aqueous solution of nitro- 

 muriate of gold, and exposing the mixture, in a phial 

 well closed, to the heat of boiling water ; but the exper- 

 iment did not succeed. 



By pouring upon this mixture a small quantity of oil 

 of olives and exposing it again to the heat of boiling 

 water, the gold was revived. 



Is it not probable that the reason why the oxide was 

 not reduced by alcohol is the mobility of those ele- 

 ments, which ought to act on each other, in order that 

 the effect in question may be produced ? There is 

 reason to think the oxide would be reduced, could the 



