gallery.] natural history. (Minerals.) 61 
massive, in detached crystals and as grains (in the alluvial deposits of 
Guinea, Sumatra, Bengal, Brazil, Leadhills in Scotland, &c.), also in 
brown iron-stone, in quartz, with needle-ore, &c., in Siberia;—the 
alloyed gold (principally from Transylvania) crystallized in minute 
cubes and octahedrons variously aggregated, in reticular plates, &c. 
Of the native alloys known by the names of electrum , that of Smeof or 
Schlangenberg, in Siberia, is best known: it is said to contain one-third of 
silver; but in general the two metals do not unite in definite proportions. 
In this Table Case begin (continued to Case 12) the electro-negative 
metallic substances called metalloids by Berzelius, and their non- 
oxidized combinations.— Tellurium and tellurets: the scarce native tel¬ 
lurium, which element (like sulphur and selenium) has the property of mi¬ 
neralizing several metals, combining with them as electro-negative sub¬ 
stance, viz_with bismuth (a compound formerly called molybdena-sil- 
ver) from Bastnaes: to which also belongs the tetracfymite ;—with silver 
( tellur-silber of G. Rose), from the Savodinsky mine, Altai, Siberia; — 
with lead {foliated tellurium, or nagyagite) ;—w T ith silver and lead (ivhite 
and partly yellow tellurium, mullerine of Beudant);—with silver and 
gold ( graphic tellurium or schrift-ertz of authors; sylvanite, Haid.) all 
from Transylvania, where they occur in veins traversing greyvracke and 
porphyry.— Native antimony from Allemont, Dauphiny, and the scarce 
antimonialsilver or stibiuret of silver from the Hartz, &c. 
Case 4. Native arsenic (formerly called testaceous cobalt andscher- 
ben-cobalt), in reniform and botryoidal shapes, from Andreasberg, &c. ; 
and its chemical combinations (arseniurets)— with nickel (a variety of 
which is commonly called red or copper-nickel on account of its 
colour) ;— with cobalt , (arsenical cobalt of authors partly,) comprising 
the grey and past of the white cobalt of some mineralogists (to which 
probably belongs the bismuth-cob alt or kerstenite of some authors. 
In the opposite half of this Case are contained the substances be¬ 
longing to the orders of Carbon and of Selenium. To the former 
element are referred the diamond, anthracite, and graphite; to the 
latter the selenium metals or seleniurets. Among the specimens se¬ 
lected to illustrate the crystalline forms of the diamond are:—the 
primitive regular octahedron; the same with solid angles truncated; 
with edges truncated, forming the passage into the rhomb-dodecahedron; 
varieties of the latter, giving rise to the six-sided prismatic and the 
tetrahedral forms ; cubes w ith truncated and bevelled edges; various 
hemitropic crystals or macles of diamonds; an octahedral diamond, 
attached to alluvial gold; two others in a siliceous breccia with ce¬ 
ment of hydrous oxide of iron, and one in compact browm iron stone, 
from Brazil; models of large diamonds, &c. (with these are placed 
specimens of the alluvial rock in w 7 hich this precious substance occurs 
in the East Indies and also in Brazil, where it is knowm by the name of 
cascalhao ;)—varieties of anthracite or kohlenblende (to which maybe 
referred the Kilkenny coal), from various localities, wdth native silver 
from Kongsberg, &c.;— graphite (commonly called black-lead), massive 
(the purest and most compact variety of which is that from Cumber¬ 
land), disseminated in porcelain earth, &c. 
Selenium : found in chemical combination with several metals; 
the seleniurets here deposited are: lead-seieniuret ( clausthalite , Beud.); 
—copper-lead-seleniuret:—mercury seleniuret (onofrite, Haid.) from 
San Qnofre. Mexico;—mercury lead-seieniuret;—cobait-lead-seleni- 
