104 



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 quantities 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 2- 14, azotic gas T20, 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- 7 6 of 

 gas; which, being analysed, was found to consist of 3 '3 8 carbonic 

 acid, and T38 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 atmo- 

 spheres, a quantity which, ordinarily compressed, would be equal to 

 twice, thrice, &c. the volume absorbed under the common pressure 

 of the atmosphere. 



