Page:Proceedings of the Royal Society of London Vol 1.djvu/367

Rh does not think the experiment conclusive, with regard to the existence of oxygen as an ingredient essential to the constitution of ammonia.

Mr. Davy, having in the experiments described in the late Bakerian lecture, found that a quantity of nitrogen disappeared during the action of potassium on ammonia, and that it could not be made to re- sume its gaseous state but by the agency of oxygen in water, has been from that time much occupied in determining, with certainty, all the circumstances of the process; and though he cannot yet speak with precision as to the quantities, he thinks the general results decisive with respect to a decomposition of nitrogen having been effected.

When potassium is heated in ammoniacal gas, it becomes an olive-coloured fusible substance, losing all its metallic properties, a quantity of hydrogen is evolved, and ammonia disappears.

In the Bakerian lecture it was stated, that upon heating the olive- coloured substance a part of the ammonia is recovered; but when all moisture is carefully excluded, this quantity of ammonia does not amount to one tenth part of the quantity absorbed; and even this Quantity appears to be owing to the almost unavoidable presence of moisture or oxygen.

In the present experiments, after taking all possible care to ex- clude moisture, since the glass of the vessels might possibly yield oxygen when in contact with potassium, a small tray of platina, con- taining the potassium intended to act upon the ammonia, was intro- duced into a retort containing the gas, and afterwards transferred ex. peditiously into a clean iron or platina tube made air tight, and fur- nished with a stop-cock.

In one experiment it was ascertained that 12% cubic inches of am- monia are decomposed by nine grains of potassium, and evolve 8}; of hydrogen.

In a second experiment, instead of reserving the gas for experiment, an equal quantity of potassium was used, and immediately transferred into an iron tube. The tube being then ﬁlled with hydrogen, and connected with a mercurial apparatus, was heated gradually. The quantity of gas collected previously to its acquiring a red heat, amounted to 9% cubic inches, and four inches more were collected by raising the heat to whiteness. Of the former portion, about three fourths of an inch Were ammonia; the remainder of the gas consisted of hydrogen and nitrogen, in the proportion of 8 to 3; so that the total quantity of hydrogen collected in this analysis, amounted to 16% inches, and the nitrogen to three cubic inches. If the same quantity of ammonia had been decomposed by electricity, it would have yielded 15 of hydrogen, and 6 or 7 of nitrogen; so