The elements of experimental chemistry (Volume 2).

  • Henry, William, 1774-1836.
Date:
1831
Catalogue details

Licence: Public Domain Mark

Credit: The elements of experimental chemistry (Volume 2). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    Sulphuret of manganese 55. or 1 atom 44 Protoxide of manganese 45. or 1 atom 30 100. Weight of its atom 80 Moys.—Manganese unites with most of the metals, and composes alloys; none of which are distinguished by important properties. SECTION XV. Zinc. The zinc of commerce, known by the name of syeltre, is never pure, but contains charcoal, lead, and sulphur. To purify it, zinc must be dis- solved in diluted sulphuric acid; a plate of zinc is then to be immersed in the solution, to throw down other metals which it may contain; the solution must be decomposed by subcarbonate of potassa; and the pre- cipitate, after being well washed, ignited with charcoal powder; after which it may be distilled at a white heat, from a stone-ware retort, into a receiver nearly full of water. Even after careful distillation, how- ever, zinc is still liable to contain a small quantity of charcoal. Zinc is of a brilliant white colour, with a shade of blue. Its specific gravity varies from 6.86 to 7.1, the lightest being the purest. By par- ticular treatment it becomes malleable, and may be beaten into leaves or drawn into wire, as was first announced by Mr. Silvester, in the Philosophical Magazine, vol. xxiii. In its ordinary state, zinc may be pulverized when hot, in a heated iron mortar, the pestle being also heated. (Faraday.) Zinc is melted by a moderate heat, viz., about 680° Fahr., and the fused mass, on cooling, forms regular crystals. Oxide of Zinc.—By exposure to the air at a low temperature, zinc slowly acquires a coating of grey oxide; but when kept in a degree of heat, barely sufficient for its fusion, it soon becomes covered with a similar oxide. If thrown into a crucible or deep earthen pot, heated to whiteness, it suddenly takes fire; burns with a beautiful white flame; and a white and light oxide, mixed with a little carbonate, sublimes, having a considerable resemblance to carded wool. This oxide, howev- er when once deposited, is no longer volatile; but if exposed to a vio- lent heat, runs into glass. It has been examined with much attention by Proust, who found it to consist of 80 parts of zinc and twenty oxy- gen. Gay Lussac (80 Ann. de Chim. 170) and Berzelius (81 Ann. de Ch. 170) have since investigated it, and agree in considering it as composed of Zinc 80.39 100 Oxygen 19.61 24.41 100. 124.41 The atomic weight of zinc, deducible from the composition of the