232 EXPERIMENTS OF GASES ABSORBED BY WATER. 



agitated together; and the cock b opened under mercury, 

 which afcended into the veflel. The agitation was ftill conti- 

 nued, obferving to preferve the fame level of* mercury without 

 as within the veflel ; and, when it rofe no higher, the afcent 

 was noted by means of the graduated fcale. The quantity of 

 mercury that had entered the veflel, indicated the amount of 

 abforption that had enfued. 

 Another appa- § It might, however, be objected, that the water would ac- 

 fimp! y a C glafs c l t " re a ' r a g a ' n » while poured into the veflel ; and I therefore 

 globe with a fometimes ufed large glafs globes, having long necks, accu? 

 long neck. rate jy g ra d ua ted. Thefe globes, being of very thin glafs, 



were filled with boiling water, and inverted inftantly in a trough 

 of quickfilver. When the water became cold, the mercury 

 was, of courfe, found to have rifen partly into the veflel. This 

 portion was difplaced by a meafured quantity of gas; and the 

 abforption was denoted by the afcent of the mercury in the 

 graduated neck. 

 General proceed- The water employed in thefe experiments was boiled, during 

 lions!" C3U " fecial hours, in a tin veflel having an aperture barely fufficient 

 to allow the egrefs of the fleam, and poured, while boiling hot, 

 into glafs veflels, which were corked, and tightly tied over 

 with bladder. An equable temperature was produced in the 

 water, mercury, and gas, except when above 85°, by regu- 

 lating that of the room in which the experiments were made; 

 and the glafs veflel, during agitation, was carefully guarded 

 from the warmth of the hand. The agitation was continued, 

 till it appeared, by the fcale, to produce no further effect ; 

 and, in the abforption of difficultly condenfible gafes, was re- 

 peated at intervals, during a«fpace of from twelve to twenty- 

 four hours. Alterations of the barometer were always ob- 

 ferved ; and the refiduary gas meafured, or eflimated, at a 

 preflure of 29 £ inches. 



I . Abforption of Carbonic Acid Gas by Water. 



Carbonic acid That the temperature of water influences the proportion of 



gas lefs abforb- caibonicacid which it is capable of abforbing, is already known 



h'gher tempe- as a general fa£t ; * but the exacl amount of this influence has 



raturcs. not, I believe, been hitherto afcertained. In the courfe of a 



* See Mr. CavendifiYs experiments in the Phil. Tranf. Vol. 

 LVI. p. 163; and Fourcroy's tyjfeme, 4to. Tom. I. p. 215. 



feries 



