250 SILVER. 



Klaproth gives, lead 41, silver 9*25, antimony 21*5, iron 1*75, 

 sulphur 22, alumina 1, silica 0-/5. It is found near Freyberg, in 

 Saxony. 



Sp. 8. Grey Silver Ore. — Argent carbonate, Hauy. — Its 

 colour is ash-grey ; it occurs massive and disseminated. The 

 fracture is fine-grained, uneven, with a glistening metallic lustre. 

 It is soft, sectile, and somewhat brittle. Its constituent parts are, 

 silver 72"5, carbonic acid 12, oxide of antimony and a trace of 

 copper 15"5. It is found in a vein at Altwolfatch, in the Black 

 Forest. 



Sp. 9. Horn Silver. — Hornerz, Werner; Argent muriate, 

 Hauy, iii. p. 418-422; Brong. ii. p. 25G ; Corneous Silver Ore, 

 Jameson, iii. p. GO. — Its colours are pearl-grey, greenish-grey, 

 also blue and leek-green. It occurs massive and crystalized, in 

 small cubes, octahedrons and rhomboidal dodecahedrons. It is more 

 or less translucent, with a glistening or waxy lustre. It is very 

 soft, and yields to the pressure of the nail. Tts specific gravity is 

 about 4*8. It is fusible in the flame of a candle ; before the blow- 

 pipe on charcoal it yields a metallic globule, giving out at the same 

 time vapours of muriatic acid. A specimen from Peru yielded, 

 silver 76, muriatic acid 16'4, oxygen 7'6. It is found sparingly at 

 Huel- Mexico, in Cornwall | but is very abundant in some of the 

 silver mines of Potosi, in South America. 



Sp. 10. Bismuthic Silver. — Wismuth Silbererz, Werner ; 

 Bismuthic Silver Ore, Jameson, iii. p. 58. — Its colour is pale lead- 

 grey. It occurs disseminated ; and rarely crystalized in acicular 

 and capillary crystals. Its lustre is glistening and metallic. Its 

 fracture is fine-grained, uneven. It is soft, sectile, and somewhat 

 brittle. It consists, according to Klaproth, bismuth 27, lead 33, 

 silver 15, iron 4, copper 0*90, sulphur lb'-30. This ore has been 

 found only in one mine, in the Schapbach, in the Black Forest, 

 where it occurs in veins that traverse gneiss, along with copper 

 pyrites, quartz, iron pyrites, and galena, or lead glance. 



" Silver is extracted from its ores by two processes which are 

 essentially distinct ; one of them being contrived to separate it 

 from lead, the other, the process by amalgamation, being especially 

 adapted to those ores which are free from lead. The principle of 



