The decomposition of the fixed alkalies and alkaline earths / H. Davy.

  • Davy, Humphry, Sir, 1778-1829.
Date:
1902
Catalogue details

Licence: In copyright

Credit: The decomposition of the fixed alkalies and alkaline earths / H. Davy. Source: Wellcome Collection.

    17/60 (page 13)
    come in equilibrium with each other; and when these are in a low state at common temperatures, a slow combina- tion is effected; but when they are exalted by heat, a rapid union is the result; and as in other like cases with the production of fire.—A number of circumstances relating to the agencies of the bases of the alkalies will be immediately stated, and will be found to offer con- firmations of these general conclusions. IV. On the Pi'operties and Nature of the Basis of Potash. After I had detected the bases of the fixed alkalies, I had considerable difficulty to preserve and confine them so as to examine their properties, and submit them to experiments; for, like the alkahests imagined by the alchemists, they acted more or less upon almost every body to which they were exposed. The fluid substance amongst all those I have tried, on which I find they have least effect, is recently distilled naphtha.—In this material, when excluded from the air, they remain for many days without considerably changing, and their physical properties may be easily examined in the atmosphere when they are covered by a thin film of it. The basis of potash at 60° Fahrenheit, the tempera- ture in which I first examined it, appeared, as I have already mentioned, in small globules possessing the metallic lustre, opacity, and general appearance of mer- cury ; so that when a globule of mercury was placed near a globule of the peculiar substance, it was not possible to detect a difference by the eye. At 60° Fahrenheit it is however only imperfectly fluid, for it does not readily run into a globule when its shape is altered; at 70° it becomes more fluid; and at 100° its fluidity is perfect, so that different globules may