Elements of chemistry, in two volumes / by John Murray.

  • Murray, John.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, in two volumes / by John Murray. Source: Wellcome Collection.

    77/768 (page 65)
    xOF EARTHS. earths to metallic oxides, they had often been supposed to be of a metallic nature, and their reduction had frequent- ly been attempted, and at one time had even been sup- posed to have been accomplished. This, however, was a mistaken result; and nothing was known with regard to their composition, until Davy, after his discovery of the chemical constitution of the alkalis, submitted the earths to the action of galvanism. Though results were obtain- ed indicating their composition, they were less perfect than those obtained with regard to the alkalis, owing part- ly to the strength of affinity between the principles of the earths,* partly to their being less perfect electrical conduc- tors. By submitting them to the galvanic action in mix- ture with potash, or with metallic oxides, results more distinct were obtained: and a method employed by Ber- zelius and Pontin proved still more successful,—placing them in the galvanic circuit with quicksilver. They thus obtained the metallic bases of barytes and lime in combi- nation %vith the quicksilver. Sir H. Davy, by the same method, decomposed strontites and magnesia. By sub- mitting silex, alumina, zircon, and glucine, to the action of the galvanic battery in fusion with potash or soda, or in contact with iron, or by fusing them with potassium and iron, appearances were obtained indicating their de- composition, and the production of bases of a metallic na- ture ; and there can thus remain little doubt, that all the earths are compounds, and of similar constitution. The metallic bases of the earths approach more nearly than those of the alkalis to the common metals, and the earths themselves have a stricter resemblance than the al- kalis to metallic oxides. Yet there are also grounds for retaining their distinction as a natural order, forming the link which connects the alkalis with the metals. Of the characters assigned to the earths, none can be VOL. II. E