NATURAL HISTORY. 
97 
GALLERY.] 
Case 4. Native arsenic (formerly called testaceous or 
scherben cobalt) in reniform and botryoidal shapes* from 
Andreasberg, &c.; and its chemical combinations (arse- 
niurets) : with nickel (commonly called copper-nickel) ; 
with cobalt, comprising the grey and part of the white 
cobalt of some mineralogists* &c. 
The remainder of this Case contains the substances be¬ 
longing to the confined orders of Carbon and of Selenium. 
To the former are referred the diamond* anthracite* gra¬ 
phite; to the latter the selenium metals or seleniurets. 
Among the specimens selected to illustrate the crystalline 
forms of the diamond are:—the primitive, regular octahe¬ 
dron ; the same with solid angles truncated; with edges 
truncated* forming the passage into the rhombic dodeca¬ 
hedron ; varieties of the latter* giving rise to the six-sided 
prismatic and the tetrahedral forms ; cubes with truncated 
and bevelled edges; various hemitropic crystals or macles 
of diamonds ; an octahedral diamond* embedded in gold ; 
another in its usual matrix; models of the largest diamonds 
known, &c. With these are placed specimens of the al¬ 
luvial rock in which this precious substance occurs in 
the East Indies and in Brazil.—Specimens of anthracite 
or kohlenblende (to which may be referred the Kilkenny 
coal)* with native silver from Kongsberg. &c.;— graphite 
(commonly called black-lead), massive* disseminated in 
porcelain earth, &c.— Seleniurets ,—only those of copper 
and silver (eukairite), those of lead and copper* and the 
selenium-sulphur* are at present in the collection. 
Case 5. The suite of specimens of sulphur (crystallized* 
massive* and stalactic* with selenite* sulphate of strontia, 
&c.; and the same found sublimed near the craters of vol¬ 
canos* &c.) is succeeded by the Sulphurets, which occupy 
half of this and seven of the succeeding glass-cases. They 
begin with sulphuret of manganese or manganese-blende* 
from Nagyag in Transylvania and from Peru.—Among 
the numerous varieties of sulphur et of zinc, or zinc-blende* 
may be particularized 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 con¬ 
tain a portion of iron; the fibrous blende of Przbram in 
Bohemia, in which cadmium was discovered by Stromeyer ; 
the variety called testaceous or schaalen blende (the most 
p 
