ISO 
LONG 
GALLERY. 
graphite , (commonly called black-lead, massive, 
disseminated in porcelain earth, &c.)—Of Se - 
leniurets , only those of copper and silver (Eu- 
kairite), of lead and copper, and the selenium 
sulphur, are at present in the collection. 
Case 4. The suite of specimens of sulphur 
(crystallized and massive, with selenite, sulphate 
of strontian, &c.; and the same found sublimed 
near the craters of volcanos, &c.) is succeeded 
by the sulphurets , which occupy half of this and 
seven of the succeeding table cases. They 
begin with sulphuret of manganese or manga¬ 
nese-blende, from Nagyag in Transylvania, and 
from Peru.—Among the numerous varieties of 
sulphuret ofzinc , or zinc-blende, maybe particu¬ 
larized 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 
others contain a portion of iron ; the fibrous 
blende of Przbram in Bohemia, in which cad¬ 
mium was discovered by Stromeyer ; the variety 
called testaceous or schaalen-blende, the most 
characteristic specimens of which are from Ge- 
roldseck in the Brisgau, contains, besides iron, 
a portion of lead. 
Case 5. — Sulphurets of iron, or iron pyrites :— 
common pyrites , smooth and striated, variously 
crystallized;— radiated pyrites, a substance very 
subject to decomposition, and to which be¬ 
long most of the varieties of what is commonly 
called 
