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.

    12/60 (page 8)
    seemed probable that the inflammable matter arose from Us decomposition. The residual potash was unaltered • It contained indeed a number of dark grey metallic par- ticles, but these proved to be derived from the platina. I tried several experiments on the electrization of potash rendered fluid by heat, with the hopes of being able to collect the combustible matter, but without success; and I only attained my object, by employing electricity as the common agent for fusion and decom- position. Though potash, perfectly dried by ignition, is a non- conductor, yet It IS rendered a conductor, by a very slight addition of moisture, which does not perceptibly destroy Us aggregation; and in this state it readily fuses and decomposes by strong electrical powers. A small piece of pure potash, which had been exposed for a few seconds to the atmosphere, so as to give con- ducting power to the surface, was placed upon an insulated disc of platina, connected with the negative side of the battery of the power of 250 of 6 and 4, in a state of intense activity; and a platina wire, communicating with the-positive side, was brought in contact with the upper surface of the alkali. The whole apparatus was in the open atmosphere. Under these circumstances a vivid action was soon observed to take place. The potash began to fuse at both Us points of electrization. There was a violent effervescence at the upper surface; at the lower, or negative surface, there was no liberation of elastic fluid ; but small globules having a high metallic lustre, and being precisely similar in visible characters to quicksilver, appeared, some of which burnt with explosion and bright flame, as soon as they were formed, and others remained and were merely tarnished, and finally covered by a white film whieh formed on their surfaces.