166 NATURAL HISTORY. [NORTH 
brown iron-stone, in quartz, with needle-ore, &c., from 
Siberia; the alloyed gold (principally from Transylvania) 
crystallized in minute cubes and octahedrons variously 
aggregated, in reticular plates, &c. With these are placed 
a few specimens of the alloys known by the names of au¬ 
riferous silver and electrum . 
In this Case begin (continued to Case 12) the electro¬ 
negative metallic substances (metalloids), and their not 
oxidized combinations. — Tellurium and tellurets : the 
scarce native tellurium , which (like sulphur ana sele¬ 
nium) has the property of mineralizing several metals, 
combining with them as electro-negative substance, viz.— 
with bismuth (formerly called molybdena-silver) from 
Bastnaes ; to which also belongs the tetradymite ;—w 7 iih 
silver , from the Altai, Siberia:—with lead (foliated tel¬ 
lurium, or nagyag ore) ;—with silver and lead (white and 
partly yellow’ tellurium);—with silver and gold (graphic 
tellurium or schrift-ertz of authors), all from Transyl¬ 
vania.— Native antimony from Bauphiny, and antimonial 
silver or stihiuret of silver from the Hartz, &c. 
Case 4. Native arsenic (formerly called testaceous cobalt 
and scherben-cobalt) in reniform and botryoidal shapes, 
from Andreasberg, See. ; and its chemical combinations 
(arseniurets): — with nickel (commonly called copper-nickel); 
—with cobalt, comprising the grey and part of the white 
cobalt of some mineralogists;—with bismuth ( kerstenite .) 
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, and 
graphite; 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, attached to some 
alluvial gold ; two others in a siliceous breccia with cement 
of hydrous oxide of iron, and one in compact brown iron 
stone, from Brazil; models of large diamonds, &c. With 
these are placed specimens of the alluvial rock in which this 
