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.

    63/768 (page 51)
    CHAR III. OF SODA. Soda being found more extensively diffused in the mine- ral kingdom than either of the other alkalis, has been de- nominated Mineral Alkali. The term Soda is that usual- ly applied to it, and is unexceptionable. On the discovery of the composition of potash, Sir H. Davy submitted soda to the same method of analysis, and discovered that it affords a base of a similar nature. It required for its decomposition rather a greater degree of galvanic power than potash did ; but when this was applied in sufficient intensity, the phenomena were similar ; an ef- fervescence was produced at the positive side, which was found to arise from the disengagement of oxygen gas ; and at the surface in contact with the negative wire, globules were produced having metallic lustre. This matter, ex- posed to the air, absorbed oxygen, and reproduced Soda: the same result took place more speedily, and with the phenomena of combustion, when it was heated in oxygen gas, or when dropt into water,—a solution of soda was formed, with an extrication of hydrogen gas. These re- sults proved, that the soda was decomposed by the gal- vanism, that the oxygen disengaged at the positive pole is derived from it, and that the metallic matter which col- lects at the negative side, Sodium, as it is named, is the base with which the oxygen had been combined. The same theory is probably to be adopted with regard to this as with regard to potassium; namely, that what we call sodium is a compound of the real base with hydrogen. d 2