of Silver hi to Gohi. 1 9 



fared me, that when filver is revived in this manner, it is in 

 part converted into gold. Since that time I have frequently 

 re-diffolved in pure nitrous acid the filver which I obtained 

 from horn filver, and always found a fmall quantity of black 

 powder remaining at the bottom, w hich feemed to have all 

 the properties of gold. 



Myprocefs for reviving the horn filver is perfeftly fimple: 

 I pour into a deep crucible a bottom of alkali an inch high, 

 and form in it a hemifpherical cavity with the round ead of 

 a cupel rammer. I then put the horn filver, well pounded, 

 and mixed with as much alkali (neither of them moiftened), 

 into this cavity, cover the whole with a thin ftratum of 

 alkali, and apply a flow heat, till the whole mafs comes to 

 red fufion; by which means the revived filver is enabled to 

 fink down and coiled itfclf at the bottom. As vegetable 

 alkali (potafli) produces the fame effeft as the mineral (foda), 

 I employ the former bccaufe it is cheaper. I find by ex- 

 perience, that, to form a moift ball of the horn filver and 

 alkali, is not only unnecefl'arv, but even prejudicial ; for the 

 moift mixture is tenacious, and unavoidably adheres to the 

 fingers and the veflels, thereby caufing wafte. As the horu 

 filver is fo extremely fufible, and at the fame time a flux for 

 earths, and as it cafily penetrates the crucible, the principal 

 obje6l in reviving, according to the above method, is to in- 

 creafe the heat by very flow degrees, fuflcring the charc(Kil 

 to burn only gently for two hours around the bottom of the 

 cmcible, that the horn filver may be in a ftate of fufion 

 before the crucible has been long ignited. By thefe means 

 the alkali is enabled to join itfelf gradually to the muriatic 

 acid, and at the fame time fo completely that, when the 

 lieat is increafed till the alkali is in a red fufion, there is no 

 longer horn filver but metallic filver prefent, which there- 

 fore may come in contaft with tlie crucible without any 

 danger. 



For diffolving the revived filver I employ nitrous acid, 



which I firft purify a carytcs from the fiilphuric acid, and 



C 2, i^ftervv :irds 



