GOLD MINES IN FRANCE. OgJ 



been cast into ingots, and sent to Paris, to the count of 

 Provence, in 1786. 2. The gold ore, winch, not being sufli- 

 jcieutly rich for the furnace, and affording instructive speci- 

 mens for the mineralogist, was set aside at the suggestion of 

 Mr. Schreiber, to be sold according to its intrinsic value to 

 curious and scientinc collectors, as is customary in the mines 

 of Saxony and Austria. 3. The rock crystals which have 

 been collected in the cavities of the quartz. 



The processes followed in the extraction of the gold are Method of ex- 

 simple, and easy to conceive. The native gold requires only tr " d tins * e 

 %o be separated from its gangue and united together. 

 For this purpose it is pounded ; washed, to carry off the 

 gangue reduced to line powder; and triturated with ten or 

 twelve times its weight of mercury in a mortar filled with 

 water. This water being decanted off carries with it every 

 thing earthy. The amalgama being separated from the 

 earth, and perfectly brilliant, it is pressed in leather bags, to 

 strain out the superfluous mercury from what is requisite to 

 dissolve the gold. The solid amalgama left behind is dis- 

 tilled in retorts, which are brought to a strong red heat, to 

 obtain the mercury separate ; and the gold, which remains 

 behind, is melted and cast in bars or ingots. 



The gold combined or disseminated in the ores of silver, 

 copper, lead, &c, is extracted by eliquation, cupellation, 

 and parting. The lead that runs during the eliquation of 

 the argentiferous and auriferous copper carries with it the 

 silver and the gold. This mixture is cupelled to scorify the 

 lead* The gold and silver that remain are separated from 

 each other by parting with nitric acid. 



It has been proposed, to treat the auriferous pyrites by 

 amalgamation, the success of which, as already confirmed 

 in Germany and Peru, proves, that the gold iu them is 

 simply disseminated, and not combined. 



The working of the gold mine of la Gardette has been Not wrought 

 suspended ever since the year 1788, yet it ought not to be since 1788 * 

 given up. It is at present under the superintendauce of 

 the mayor of Villard-Eymont. The distance, difficulty of 

 access, complete ruin of the miner's house, falling in of the 

 earth, and general decay of the mine, has occasioned it to 

 be neglected by the local authorities; aud the inhabitants 



of 



