372 



Analysis of 

 this ore. 



Mingled with 

 carbonat. 



Large piece of 

 native silver in 

 the Cabinet du 

 Roi. 



rcrta kes 

 from oxides of 

 iron part of 

 their oxigen sX 

 a high tempe- 

 rature, and 



This muriat Is transparent, pearly, and may be cut with* 

 out splintering. Its chips assume the violet tint in a 

 few minutes on exposure to the sun. It may be melted in 

 a retort, without losing any of its characteristics, or di- 

 minishing in weight. If it be brought near the flame of 

 a candle, it flows in red drops like the juice of a goose^ 

 berry, which grow white on cooling. They should be 

 caught on a plate of glass. The artificial muriat yields 

 likewise coloured drops when melted. The native muriat 

 enclosed in a sheet of lead does not yield above 74 and a 

 small fraction of silver, though it contains 75|. 



I decomposed a hundred parts of this muriat by means 

 of zinc, and precipitated the solution with nitrat of sil- 

 ver. The product collected was a hundred parts. I liad 

 the same result twice. The solution of silver may be 

 employed, which will remain mingled with zinc after the 

 decomposition has taken place ; but as the necessity of 

 filtration occasions a slight loss, only 98 or 99 will be 

 obtained. The muriat reproduced should not be weighed, 

 till it has been thoroughly dried. 



The muriat is likewise found mixed with carbonat of 

 silver in powder, exhibiting a perfectly uniform grey 

 paste. It is very diflScult to break. Rubbing it with 

 any hard body will make the silver shine. I have one 

 piece which consists of silver 30, carbonat of lime 32, 

 muriat 38. 



As far as I can judge from a^ppearances, it is this paste 

 that incloses. the celebrated piece of native silver preserved 

 in the King's collection. This piece, weighing near three 

 hundred pounds, ^is still loaded with part of its valuable 

 coat. If the miner had not robbed it of the rest, it 

 would have been much more precious to the mineralogist. 

 It appears to have been considerable. It was cut off 

 with a hammer and chissel. This specimen came from th» 

 mines of Quantacaia, on the borders of the Pacific 

 Ocean. 



Silver is likewiseamong the number of metals Capable 

 of taking from iron that portion of oxigen, which raises 

 it from the minimum to the maximum of oxidation, or 

 which is included between 28 and 48 per cent. But for 

 this it must be assisted by a certain degree of heat ; for 



on 



