BISMUTH 



347 



Native bismuth has boon found, associated with other minerals, in Cornwall, at 

 Dolcoath near Camborno ; at Huel Sparnon, near Rodruth, when that mino was 

 worked ; at Trugoo Mino, near St. Colomb (Grog), and at the Consolidated Mines, 

 St. Ivcs ; Caldbeck Fells, in Cumberland, with ores of cobalt. But the most abun- 

 dant sources of native bismuth are tho silver and cobalt mines of Saxony and Bo- 

 hemia, especially those of Schneeberg, Annaberg, Marienberg, Altenberg, Joachimsthal 

 and Johanngcorgenstadt. It is also found at Sorato, in Bolivia. 



Bismwthinc, Bismuth glance, or sulphide of bismuth, occurs either in acicular crys- 

 tals, or with a foliated, fibrous structure. It is isomorphous with stibnite. or sulphide 

 of antimony. Hardness, 2 to2'5: specific gravity, 6'4 to 6 - 9. It is composed of 

 bismuth, 81'25; sulphur, 18'75. It fuses in the flame of a candle. 



Bismuthine occurs in Cornwall, at Botallack, and associated with tin at St. Just, 

 and with copper at the mines near Redruth and Cambornc. Large quantitic^ are now 

 worked and smelted in South Australia. 



Acicular Bismuth, or Aikinitc, called also Needle Ore, is a plumbo-cupriferous 

 sulphide of bismuth, composed of sulphur, 16 ; bismuth, 34'62 ; lead, 35'60 ; copper, 

 11-79. 



Emplectitc, or Tanncnite, is a rare mineral, containing sulphur, 18 - 83 ; bismuth, 

 62-16; copper, 18-72. 



Telluric Bismuth, or Tetradymite, occurs in Cumberland, at Brandy Gill, Carrock 

 Fells (Greg), and at Dolgelly in Merionethshire. 



The purest varieties contain only bismuth and tellurium, in proportions represented 

 by the formula, Bi 2 Te 3 , corresponding to tellurium, 48'1, and bismuth, 51'9 per cent. 

 Other varieties contain sulphur and selenium. It is notable that tetradymito is often 

 found associated with gold. 



Bismuth Ochre. A dull earthy mineral, found in the Royal Restormol Iron Mine, 

 and in small quantities in the parish of Roach, in Cornwall. Its composition is stated 

 by Lampadius to be : Oxide of bismuth, 86'4 ; oxide of iron, 5'1 ; carbonic acid, 4'1 ; 

 and water, 3*1. 



Carbonate of Bismuth, or Bismutite. This ore is composed of a mechanical mixture 

 of tho carbonates of bismuth, of iron, and of copper. 



Eulytinc or bismuth-blende is a silicate of bismuth, occurring in small crystals in 

 the mines of Schnoeberg, in Saxony. 



Bismuth, which was formerly known as Marcasite and as tin-glance, was shown to 

 be a metal ' somewhat different from lead' by G. Agricola, in 1546. It was studied 

 by Stahl and Dufay, and still more minutely by Pott and Geoffroy, about the middle 

 of the last century. 



This metal, tho demand for which is limited, is chiefly procured in Saxony, from 

 the mines of Schneeberg ; where it occurs mixed with cobalt speiss, in the proportion 



105 





of about 7 per cent. In the metallurgical works at Schneobcrg tho metal is obtained 

 by means of a peculiar furnace of liquation. This furnace is represented in figs. 105 

 and 106, of which tho first is a view from above, the second a view in front; and 

 fig. 107 is a transverse section on the dotted lino A, B, of fig. 106. a is the ash-pit; 

 h, tho fire-place ; c, the eliquation pipes ; d, tho grate, of masonry or brickwork, upon 

 which tho fuel is thrown through the fire-door, e c. The anterior deeper-lying 

 orifice of tho eliquation pipes is closed with tho clay-plate, f, which has beneath a 

 small circular groove, through which the liquefied metal flows off; g is a wall extend- 

 ing from the hearth-sole nearly to tho anterior orifices of the liquation-pipes, in 



