Page:Proceedings of the Royal Society of London Vol 1.djvu/366

Rh nitrogen, are in a gaseous state, composing a mixture which may be detonated with a fresh addition of oxygen; and in this way all the hydrogen may be saturated with oxygen, and the nitrogen may be obtained as a ﬁnal result of the process.

From a set of experiments thus conducted, the proportion of hy. drogen to the nitrogen in ammonia was pretty uniformly 706 to 29-4; but there was some irregularity in the entire quantities of both, the highest results being as much as 2006, and the lowest only 182 from 100 of alkaline gas; a diﬁerence which Dr. Henry cannot fully explain, but supposes it may arise from absorption of ammonia b'y mercury, and subsequent liberation by the shock.

The letter concludes with the mention of some experiments on the electrization of carburetted hydrogen, oleﬁant gas, carbonic oxide, and carbonic acid.

Carburetted hydrogen and oleﬁant gas were each expanded con- siderably in bulk; no carbonic acid was generated, but charcoal was deposited on the surface of the tube.

Carbonic acid was also partially decomposed by long electrization, and was converted into carbonic oxide and oxygen; and accordingly carbonic oxide underwent no change by the same operation.

Some Observations on the foregoing Paper of Dr. Henry: By Hum- phry Davy, Es.

Mr. Davy, having lately had much occasion to pay particular at- tention to the electrization of ammonia during his researches on the decomposition of nitrogen, has observed various sources of error that may occur in the process, and may account for the difference between his results and those of Dr. Henry.

The ﬁrst precaution that is to be taken, is to boil the mercury over which the decomposition is to be eﬁ'ected; next to prepare the gas in a separate vessel, and thence _transfer it to the boiled mercury for electrization; for unless these precautions are taken, water contained in the mercury becomes the cause, of that absorption of ammonia suspected by Dr. Henry, and by thus adding fresh ammonia during the process, occasions a fallacious result.

A second error may also be occasioned, when the mercury has not been boiled, by common air adhering to the sides of the tube.

In a late experiment, Mr. Davy obtained from 15 measures of ammonia 27 of permanent gases, consisting of 73 hydrogen and 27 nitrogen, agreeing so nearly with his original results of 74 to 26, that he conceives either of them to be more near the truth than Dr. Henry’s estimate of 71% and 28%.

With respect to Dr. Henry’ s attempt to prove the existence of oxygen in ammonia by the formation of water, Mr. Davy does not see much probability of success, as water existing in ammonia may elude any hygrometrical test. And although in his own electrization of ammonia the platina wires were tarnished, at the same time that the ammoniacal gas seemed to lose weight during decomposition, he