GALLERY.] NATURAL HISTORY. (Minerals.) 
49 
earthy manganese or wad, (a name also frequently given to earthy cobalt 
and to other metallic substances in a state of decomposition,) some 
varieties of which exhibit spontaneous combustion when mixed with 
linseed oil. 
Case 14. In this and the two following Table Cases are deposited 
most of the oxides of iron :— magnetic iron-ore or magnetite (magnet- 
eisenstein of Werner), a compound of protoxide and peroxide of 
iron, most of the varieties of which are strongly attracted by the magnet, 
while some^of them possess polarity in a high degree (^natural magnets), 
of which several specimens are here deposited:—among-the more 
interesting crystallized varieties may be particularized those from Tra- 
versella in Piedmont: among the granular varieties that from the East 
Indies, which yields the wootz, or salam-steel, remarkable for its hard¬ 
ness ;— magnetic iron-sand. 
Case 15. Iron-glance or specular oxide, among the specimens of 
w^hich those from Elba are much admired for their beautiful iri¬ 
descence and play of colours; the variety in large laminar crystals 
appearing like polished steel, from Stromboli and Vesuvius;—the 
micaceous iron-ore of Werner, belonging partly to this species, partly 
to hydrous oxide of iron;—also the red iron-ore, generally divided 
into compact red iron-stone and red hematite, are now considered as 
a variety only of this species. 
Case 16. Hydrous oxide of iron or brown iron-stone, among the 
most remarkable varieties of which species are, the micaceous, called 
gdthite, in delicate transparent tables of a blood-red colour; that in fine 
scales coating the cells of lava ; a shining brownish-black variety used 
as hair powder by the Bootchuana natives beyond the Great River in 
South Africa; the fibrous brown iron-stone or brown hematite ; the 
compact and the ochrey brown iron-stone. With these are placed speci¬ 
mens of several sub-species of argillaceous or clay iron-stone, such as the 
columnar, thereniform, the pisiform (pea-ore): among the varieties here 
deposited of this latter, is a sample of the rounded and angular grains 
from the size of a millet-seed to that of a small hazel nut, which, on the 
10th of August, 1841, descended as a shower at Iwan, in the Comitate 
of Oedenburg in Hungary, and were considered as a new species of real 
meteorites, until their terrestrial origin w'as fully ascertained by micro¬ 
scopic observation and analysis. 
Case 17. Oxide of copper:—red or ruby-copper {cuprite, Haid.), 
compact and foliated, of which the finest crystallized varieties occur 
in the Bank mines, Siberia, and in Cornwall: one of the more re¬ 
markable varieties is the bright-red capillary cuprite called chalco- 
trichite, (in which selenium has been found by Kersten,) from Rhein- 
breitenbach;—the tile-ore, most varieties of which are intimate mixtures 
of red copper and brown iron-ochre, from Hungary, Siberia, &c. ;—the 
tenorite of Semmola, a pure oxide of copper occurring in six-sided 
filmy plates, on the rifts of some Vesuvian lavas;—the black oxide or 
melanoconite, generally found mixed with the oxides of iron and man¬ 
ganese. Oxide of bismuth or bismuth-ochre, from Saxony and Bo¬ 
hemia.— Red oxide of zinc {zincite of Haidinger, also called spar- 
talite and sterlin gite),irom Sparta in New Jersey; to which is added, 
from the same locality, the franklinite, a mineral composed of the oxides 
of zinc and manganese.— Black and yellow earthy cobalt, both called 
