ACIDIFEROUS EARTHY MINERALS. Under this head are comprehended those minerals which chiefly consist of an earth combined with an acid; some of them include variable proportions of oxide of iron, which may be considered only as an incidental ingredient. SUBSULPHATE OF ALUMINA. Aluminite, J. AVebsterite, Levy. Alumine Sous-sulfatee. Combination of sulphuric acid, alumina, and water. Halle. Newhaven. Auteuil. Sulphuric acid 23-36 23-27 23-0 Water 46-33 46-76 47-0 Alumina 30-26 29-87 30-0 Stromeyer. Dumas. Sp. Gr. 1-669. In reniform masses and botryoidal concretions, of a white or yellowish-white colour, occasionally translucent, but more frequently dull and opakc, with an earthy fracture; it yields to the nail, is meagre to the touch, and adheres to the tongue. It fuses with difficulty before the blowpipe, but dissolves readily in acids, without effervescence. It imbibes water, but does not in consequence fall to pieces. It occurs imbedded in ferruginous clay, which rests on the chalk strata on the coast near Newhaven in Sussex; also at Epernay in 1-ranee, and in plastic clay at Halle on the Saale in Prussia.