Volume 1

A manual of chemistry / by William Thomas Brande.

  • William Thomas Brande
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: A manual of chemistry / by William Thomas Brande. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

    1260/1276 (page 1130)
    and some 9 atoms of water; the former are oblique rhombic prisms, the latter rectangular prisms. (Fritzsche. Poggend., xLiii. 135.) Tcrsilicale of Soda, Na0,3Si02, is obtained by fusing together 100 parts of pulverized silica, and 40 of caustic soda: on rapidly cooling the resulting glass it is transparent, but if slowly cooled, it exhibits cry- stalline points; it is brownish, and contains about 24 per cent, of soda. (Dumas.) When 3 parts of powdered quartz and 2 of dry carbonate of soda are fused together in a platinum crucible, the glass which results, after having been ivashed with cold water, yields a solution in boiling water from which alcohol throws down a white precipitate; when this is redissolved in water, and again precipitated by alcohol, it forms a trans- parent substance on drying, which is a tersilicate: this is said to be the compound held in solution in the waters of the geysers, or boiling foun- tains of Iceland. (Forchammer. Poggend., xxxv. 343.) A hydrated Quatersilicate of Soda, NaO,4SiO,12HO, was obtained by Walcker (Quart. Journ. Science and Arts, 2nd Ser., iii. 371,) by saturating a boiling solution of caustic soda with precipitated silica, filtering, evaporating, and drying the residue at 242°: it is a pale yellow transparent glass, deliquescent, and difficultly soluble in water: when heated to redness it loses water, and becomes a spongy and very diffi- cultly fusible mass which does not attract aerial moisture. Silicate op Lime. Silica and lime may be combined by fusion, but the results of their mutual action have not been minutely examined. Under the article Glass, in Aikin’s Dictionary, some valuable facts will be found in reference to these combinations. There are some minerals which are silicates of lime. Table spar, or Wollastonite, is Ca0,Si02. (II. Rose.) Dauburite is Ca0,Si02,H0; (Shepard, Silliman’s Amer. Journ., xxv. 137;) and Okenite, or Dys/clasile, is Ca0,2Si02,2II0. (Kobkll.) Apophyllite is a hydrated silicate of lime and potassa, the formula of which is KO,8CaO,ioSi02,16IIO. (Stromeyer.) Silicate of Baryta. -2 parts of silica and 1 of baryta fuse together into a porous slag. A similar combination may be obtained with strontia. (Kirwan. Vauquelin.) Silicate op Magnesia. Several minerals appear to be definite com- pounds of silica and magnesia. Olivin, and chrysolite, are disilicates of magnesia = 2Mg0,Si02, with variable proportions of oxide of iron. Villarsite, a mineral analyzed by Dufrenoy, (Comptes liendus, xiv. 698,) is 2[2Mg0,Si02] + HO; and the varieties of noble serpentine are hydrated subsilicates of magnesia. In the slags of smelting furnaces crystallized products are not unfrequent, which are double silicates of lime and magnesia. (Berthier; Mitsciierlich, Ann. Ch. el Ph., xxiv. 355.) Equal weights of lime, magnesia, and silica, may be fused into a green glass, which strikes fire with steel. (Aciiard.) 1 atom of lime, 1 of magnesia, and 2 of silica yield a pale bluish-green glass with granular fracture. Sefstrom and Berthier have described several of these double silicates, and a great variety of minerals arc similarly constituted. Silicates of Manganese. By fusing together 1 atom of silica and 2 of protoxide of manganese, Berthier obtained a crystalline silicate lescni-