206 On the Composilion of the Gold from California, 



by treating them with aqua-regia, separating the chloride of 

 silver, after dilution, by decantation of the solution of gold, 

 and the chloride of silver, after having been well washed, dried 

 and weighed, was dissolved in ammonia, leaving a white sili- 

 ceous residue, but no gold. The solution of the gold was, 

 after the destruction of the nitric acid by heat and hydrochlo- 

 ric acid, digested with oxalic acid until all the gold was pre- 

 cipitated ; the acid solution from the precipitated gold was 

 treated with sulphuretted liydrogen ; the precipitate of sul- 

 phuret of copper produced was ignited strongly, the metal 

 estimated from the oxide and a minute button of metallic 

 copper was procured from this by the blowpipe. After the 

 precipitation of the copper, the solution was evaporated to 

 dryness, the oxalic acid was expelled by heat, leaving a minute 

 quantity of chloride of iron*, which was dissolved in water aci- 

 dulated by hydrochloric acid and precipitated by ammonia. 

 The gold precipitated by the oxalic acid was entirely dissolved 

 by aqua-regia. In this manner these grains were found to be 

 composed of per cent. — 



Or after abstraction 

 of siliceous matter. 



Gold 88*75 . . . 90-01 



Silver 8-88 . . . 9-01 



Copper with trace of iron 0*85 . . . 0*86 



Siliceous residue . . . 1*40 



99-88 99-88 



The larger piece or "pepite" weighed 30*92 grains, and its 

 specific gravity was 15-63. After being flattened out on a 

 polished steel anvil until it appeared free from foreign matter 

 and gently ignited, it weighed 30-24 grains, and the specific 

 gravity was now found to be 16-48. 



10-96 grains, mostly of this larger piece, were analysed in 

 the manner described above, and were found to consist of in 

 100 parts, — 



Gold 86-57 



Silver 12*33 



Copper 00-29 



Iron 00*54 



99-73 



0-688 grain of this larger mass, assayed by the blowpipe by 

 the method described by Plattnerf, gave 86-33 per cent, gold ; 

 and a very thin spangle, which weighed 0*483 gr., and after 



* Unless the oxalic acid has been prepared by sublimation, a small quan- 

 tity of carbonate of lime will be left after dissipation of the acid. 

 •j- Probirkunst mit dem Lothrohre. Leipzig, 1847. 



