GALLERY.] NATURAL HISTORY. 161 
yellow earthy cohalt , both called cohalt-ochre , which seem 
to be hydrates of the oxides of cobalt and manganese, 
frequently mixed with oxide of iron.— Oxide of uranium, or 
uran-ochre , and the hydrous protoxide of the same, called 
pitch-ore . 
Case 18. Oxide of tin or tinstone, divided by Werner 
into common tinstone and wood-tin : among the speci¬ 
mens of the former (chiefly from Cornwall, Saxony, and 
Bohemia) may be specified the greyish-white crystals re¬ 
sembling scheel-ore or tungstate of lime, the regular and 
macled crystals, the pebble-like and granular tin-stone 
(shoad-tin, stream-tin, grain-tin, &c.), the columbiferous 
oxide of tin from Finbo in Sweden; a variety of fibrous 
oxide or wood-tin, composed of radiated-fibrous small glo¬ 
bules, and marked with concentrically disposed brown and 
yellow colours, is called toad's eye w T ood-tin. 
In the next Case begin the oxides of electro-negative 
bodies, and their various combinations. 
Case 19. Alumina and Aluminates. To the former 
belongs the corundum, comprehending the precious stones, 
commonly called oriental gems (the sapphire, ruby, orien¬ 
tal amethyst, oriental topaz, oriental emerald), of the crys¬ 
tallized forms of which the principal modifications are 
here deposited; and the common or imperfect corundum 
from Bengal, Mysore, China, the Carnatic (Werner's dia¬ 
mond spar), Lapland, Piedmont, &c. As appendix to 
these are added, the Jibrolite, (bournonite of Lucas,) one 
of the concomitant substances of the common corundum of 
the Carnatic ;—the indianite of Bournon, being one of the 
matrices of the same corundum;—the emery, which owes its 
hardness and consequent usefulness in polishing to an ad¬ 
mixture of blue corundum.—The diaspore and the gihh - 
site : both hydrates of alumina. 
Aluminate of magnesia —the spinel: among its varieties 
is the blue spinel of Aker in Siidermannia. The ceylon- 
ite or pleonaste, and the automolite (also called gahnite), 
from Fahlun in Sweden and from Franklin in New Jersey, 
are, the former an aluminate of protoxide of iron and mag¬ 
nesia, the latter an aluminate of zinc. The mineral 
called gum-lead ( plomh gomme), from Huelgoet in Brit¬ 
tany : a hydrous aluminate of lead. 
