EXPERIMENTS OF GASES ABSORBED BY WATER. C 233 



feries of experiments to determine it with precifion, I was 



furprifed by obtaining remits which difTerecl conliderably from 



each other, at the fame temperature of the gas and water ; 



when boih were, in different experiments, of like purity; and 



when the barometer had the fame elevation. Of the caufe of The refults at 



thefe variations I was not aware, till my friend Mr. Dalton l ! kt tem P era " 



../.../....■, tures and pref- 



fnggefted, that they probably depended on the variable amount fures are not 

 of the reiidues • and, on repeating the experiments, with dif- conftant, unlefs 

 ,. . , , , , • r llke quantities 



ierent proportions between the gas and the water, this lug- f g a be pre- 

 geftion was fully confirmed. Thus, when two meafures of fentC(1 > 

 carbonic acid gas were agitated with one meafure of water, 

 the abforption was confidei ably greater than when, to the fame 

 quantity of water, a lefs proportion of gas was ufed. The becaufe the 

 caufe of this diminimed abforption, feems to be connected fm f !,er refidues 



... ... . .... w 'il contain a 



with the proportion or common air contained in the unab- greater prcpor- 



forbed refiduum ; for, betides the unavoidable contamination tion of common 



c .% i.-i • > .1 ; • * +t air which retains 



ot the gas employed, with a minute portion or the air ot the gas a i ong with it. 



vefTel ufed for its extrication, a fmall quantity will always be 

 liberated from the water, whatever pains have been taken to 

 deprive it of air, by previous long boiling, expofure under the 

 air pump, or both in fucceffion. That this is the true expla- 

 nation, appears alfo, from the refult of adding to the gas a 

 proportion of common air. Thus, when, at the temperature 

 of 55°, 20 meafures of carbonic acid are agitated with 10 of 

 water, at leaft 10 meafures of gas are taken up ; but, from a 

 mixture of 20 meafures of carbonic acid with 10 of common 

 air, 10 parts of water take only 6 of carbonic acid, or 4 lefs 

 than in the former inftance. 



An analogous fadt. was obferved by Dr. Brotvnrigg *, who Reverfe fa£h 



remarked that gas does not efcape from the water which it Tha J gas efca P c " 



, . r . much more 



impregnates, unlefs the water be in contact with air: for, when readily from 



the Pouhon water was excluded from air, but, at the fame time, water when lt 

 ,., , c -r - , . . . . can 2fi" ue '"to 



liberty was given tor ^ts gas to arile into an empty bladder, common air, 



the gas did not fpentaneoufly feparate from the water ; but, 



on the contrary, remained united with it, when expofed to the 



greateft heat of our climate. When the impregnated water, 



he obferves, is thus excluded from air, the gas will efcape very 



flowly, at any temperature lefs than 110° of Fahrenheit, al- 



* See Dr. Brownrigg's Paper on the Pouhon Water. Phil. Tranf. 

 Vol. LXIV. 



though 



