Page:Proceedings of the Royal Society of London Vol 1.djvu/341

Rh is inferred that the quantity of oxygen in sulphur amounts to about ten per cent., and hence the intense ignition that occurs in the union of sulphur with potassium, and other metallic bodies, is traced to a more probable source than their mere afﬁnity for sulphur.

The same analogies apply to phosphorus as to sulphur; the same mode of operating was adopted, and products perfectly analogous were obtained. By electrization, phosphuretted hydrogen was given out, and the phosphorus became of a deep red brown colour. By the action of potassium also, phosphuretted hydrogen was obtained, and by the action of acids on the residuum, it appeared that the potas- sium had gained oxygen from the phosphorus; and the same inference is drawn from the action of potassium on phosphuretted hydrogen, which appears to contain oxygen in a state of combination, similar to that which obtains in sulphuretted hydrogen.

The same new modes of research are next employed to discover what diﬁ‘erences subsist in the states of carbonaceous matter, in plumhago, charcoal, and diamond; for though late and very accurate experiments have proved that they yield very nearly the same quantities of carbonic acid, it was nevertheless not improbable that new means of analysis might detect chemical differences, correspondent to the extreme difference of their physical properties.

Plumbago, whether acted upon by the voltaic battery or by potassium, yields no elastic product in either case; but in the latter, merely combines with the potassium unaltered. Charcoal, on the contrary, by the voltaic apparatus, yielded a considerable quantity of carburetted hydrogen, but did not contribute to the oxidation of the potassium, any more than plumbago had done.

The unconducting nature of the diamond rendered it impossible to apply the voltaic battery with any effect, but it was by no means insensible to the action of potassium. When these substances were heated together, there was no intensity of action, and no production of elastic ﬂuid. But the diamond soon blackened at its surface, and was ultimately reduced to a state perfectly resembling plumbago; part of it at the same time uniting to the potassium. The addition of carbonaceous matter was not, however, the sole change that had happened to the potassium, as it now extricated a smaller quantity of hydrogen from water than an equal quantity of pure potassium, and had evidently acquired a portion of oxygen from the diamond. This quantity of oxygen (though certainly very small) is thought to be the cause of its non-conducting quality.

Mr. Davy next resumes the analysis of horacic acid, which he had begun in his last Bakerian Lecture. By means of voltaic electricity, a black matter could be obtained from it that was unaltered by water, but soluble in nitric acid, and when heated to redness, burned slowly, giving off white fumes. But the quantity of the base that could be thus obtained was too minute for determining distinctly its relation to the acid from which it was produced. However, by heating together boracic acid with potassium, a large quantity of a similar matter (as has also been observed by M. Thenard) was obtained. In