Page:Proceedings of the Royal Society of London Vol 1.djvu/124

Rh soon occurred that this might be owing to the variable amount of the residua of the gas, after the absorption; and this was actually con- ﬁrmed by the observation, that, of a greater quantity of gas, more would be absorbed than of a. smaller, though both quantities were sufﬁcient for saturation of equal quantities of water. This was found to be owing to the quantity of common air, which will ever be extri- cated from the water, though it be ever so pure, and which will form a greater proportion of the smaller than of the greater dose of the residuary gas.

A table of nine experiments is next given, in which are entered the temperature, the quantiﬁes of water and gas, the 'quantities of gas absorbed, the residua, and the quantities absorbed by 100 inches of water. The two extreme results are, that, at the temperature of 55°, 13 measures of water, exposed to 32 measures of gas, absorbed 14 measures, leaving a residuum of 18 measures; so that the ab- sorption of 100 measures of water would be 108 measures of gas. In the temperature of 110°, 20 measures of water, exposed to 20 measures of gas, absorbed 9 and left 11 ; so that 45 in 100 was the total of the absorption.

A series of experiments on other less absorbable gases have afforded for one temperature, viz. 60°, and in 100 cubic inches of water, the following results :—nitrous gas 5 inches, oxygenous gas 2'63, phos- phorated hydrogen gas 214, azotic gas 1'20, and hydrogen gas 1'08. Some experiments are next described on the quantity of atmospheri- cal air that may be extricated from water ; the general result of which is, that 100 cubic inches of common spring water will yield 4'76 of gas; which, being analysed, was found to consist of 3'38 carbonic acid, and 1'38 atmospherical air.

The object of the second section being to ascertain the ratio be- tween the addition of pressure and the increased absorption of gases by water, Mr. Henry made some alteration in his apparatus, which consisted chieﬂy in lengthening the tube, so that, by the addition of mercury, any required addition of pressure might be obtained on the water and gases.

The results of a series of at least fifty experiments on a variety of gases were, that under equal circumstances of temperature, water takes up, in all cases, the same volume of condensed gas as of gas under ordinary pressure ; but that as the spaces occupied by every gas are inversely as the compressing force, it follows that water takes up of gas. condensed by one, two, or three additional atmospheres, a quantity which, ordinarily compressed, would be equal to twice, thrice, &c. the volume absorbed under the common pressure of the atmosphere.