The principles of chemistry : illustrated by simple experiments / by Julius Adolph Stöckhardt ; translated from the 3rd German ed. by C.H. Peirce.

  • Stöckhardt, Julius Adolph, 1809-1886.
Date:
1850
Catalogue details

Licence: Public Domain Mark

Credit: The principles of chemistry : illustrated by simple experiments / by Julius Adolph Stöckhardt ; translated from the 3rd German ed. by C.H. Peirce. 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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    test-paper is not changed by it, but it turns red test- paper blue; this is a combination which may be re- garded as the opposite of acids; it is called oxide of sodium. Let this also be kept for future use. The metal sodium has such an extraordinary affinity for oxygen, that it quickly attracts it from the air. Therefore, to preserve it unchanged, it must be kept in some liquid containing no oxygen; as, for instance, in naphtha or petroleum. 68. Experiment e.— A piece of fine iron wire is so wound round a slate or common lead pen- cil, that, on the withdrawal of the latter, the wire may have a spiral form. Fasten the upper part of this wire, as in experiment c, to a cross-piece of wood, and place on the lower end of it a small portion of tinder. When this is kindled, introduce the wire into the oxygen; the burning tinder heats the iron to redness, which then burns brilliantly, throw- ing out sparks. The iron, when red-hot, combines with the oxygen. The burnt or oxidized iron (iron scales) melts, and falls to the bottom in globules, which are so hot that they are liable to melt into the glass, though it be partly filled with water. This heat, as in the preceding case, is the result of chemical combination taking place. Oxide of iron is insoluble in water, and for this reason it affects the color neither of the blue nor of the red test-paper; if it were soluble, it would, like oxide of sodium, convert the red into blue paper. 69. Such combinations of oxygen as are not acid, but agree in their properties with the oxide of sodium or of iron, are called bases or bake oxides. Most of tha combinations of the metals with oxygen belong to the bases.