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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    Fig. 24. COMPOSITION OF WATER. 55 Besides that eleetrieity, which we admire, on a Jmd scale in the majestic phenomena of lightning, Twhieh we generate on a small scale by rubbing liu bodies'together, a second kind of electricity is also recognized, which is called galvanic force, or gal- vanism. This has attained great importance in chem- istry as by means of it the chemist is enabled to de- compose almost all chemical combinations, even into their component parts or chemical elements. By gal- vanic force water can easily be decomposed into its ele- mentary parts. This sort of electricity may be gener- ated in various ways; it is developed in every chemical combination or decomposition, indeed quite frequently when heterogeneous substances, whether solid, liquid, or aeriform, are brought into contact. The oldest and most common gal- vanic apparatus is the voltaic pile, in which electricity is excited by the contact of two different metals, commonly zinc and copper. A cop- per plate placed upon one of zinc is called a pair of plates; many such pairs are laid, one above the other, each pair being separated by a piece of cloth moistened with salt water. The relative position of the met- als in each pair must be observed throughout the whole series, so that, if the pile commences with a zinc plate, it shall terminate with a cop- per one. These two extremities are