45 
all of them probably produced by the decay of 
galena. 
(Case 44.) Ores of zinc. Among the many va¬ 
rieties of sulphuret of zinc , or blende, may be par¬ 
ticularized those relative to colour, viz. the yellow, 
the brown, and the black blende of Werner; the 
first of which is generally most pure, while the two 
others contain a portion of iron ; the fibrous blende 
of Przbram in Bohemia, in which the cadmium 
was discovered by Stromeyer; the variety called 
testaceous blende (schaalen-blende), the most cha¬ 
racteristic specimens of which are from Geroldseck 
in the Brisgau, contains, besides iron, a portion of 
lead.—The other ores of zinc in this case are those 
of a sparry appearance, commonly called calamine, 
which constitute three different species, viz. the elec¬ 
tric or siliceous calamine, in a variety of which the 
presence of cadmium has lately been proved by Dr, 
Clarke; the common calamine, or native carbonate 
of zinc; and the red oxide of zinc: the specimens 
of the two former species include various crystal¬ 
line and other forms, among which are the pseudo- 
morphous crystals of carbonate of zinc, derived from 
modifications of calcareous spar. 
( Case 45.) Ores of tin, of which we have the sul¬ 
phuret of tin, or tin pyrites, and the oxides, which 
are divided into common tin stone, and wood tin:—- 
tin pyrites, hitherto only found in Cornwall, nearly 
pure, mixed with copper pyrites, &c.;—among the 
specimens 
SALOON. 
Nat. Hist. 
