CONSTITUTION OF MIXED GASES. 29^ 



certain order. But on making the experiment, with all the 



attention I could beftow, this did not prove to be the fact : 



■for fimilar meafures of impregnated water gave up equal bulks 



of carbonic acid, to like quantities of all the difierent gafes. 



The reverfe of this fatl alfo occurred to me in the cou rfe if carbonic acid 



of a feries of experiments, to which I have already referred: ^^ '""'^'' ^"'^ 



L I 1 ■ r • • I I ■ • 1 another gas, the 



VIZ. that the admixture or common air with carbonic acid gas abfr>rption by 



diminijfhes confiderably the proportion of the latter eas (aken ^^^^"^ '^ govern- 



1 -^1 , r r .'^ . . . ed by the den- 



iip by wafer. Thus, when 20 mealures of pure carbonic acid f^^y of the car- 

 gas are agitated with 10 of water, at leaft 10 meafures of gas bonic acid and 

 are abforbed. But from a mixture of 20 meafures of carbonic ^^^^ ^^ ^j^^ ' 

 acid with 10 of common air, 10 parts of water tdke only 6 of 

 carbonic acid. That chemical affinit)' between tiie mixed gafes 

 is not the caufe of the dirainifhed amount of abforption, is 

 perfe6lly clear; lince it is indifferent, as to the effeft, what 

 gas is added, and the proportion alone influences the refult. 

 The efTeft is therefore to be afcribed to the diminiflied denfity 

 of the fuperincumbent carbonic acid by mixture v/ith another 

 gas ; and the preffure of gafes being dired'y as their denfity, 

 and the quantity abforbed by water being as the preffure, the 

 abforbed carbonic acid muft neceflarlly quit the water. This 

 efcape continues till the carbonic acid above the water has a 

 denfity equal to that in the water, and no longer. 



Previoufly to my acquiefcence in your theory of mixed Wafer has no 



, , r r ■ c ■ . •■! prr fercnce of 



gafes, I undertook an extenfive leries or experiments, with a attraftion as to 



view to afcertain the order of affinities of gafes for water, the gafes. 



But, after a great variety of trials, made with all the accuracy 



jn my power, I could difcover nothing like a feries of elective 



attractions. Each gas, it was found, difplaced every other, 



and reciprocally wasdiflodged by them. 



It may be urged againft (he dodlrine of the non-gravi(ation The floxvcf 

 of gafes on each other, that from water impregnated with fi.';^'^^"^^,^!" 

 carbonic acid gas, and expofecl to the atmofphere, the j^a* poft-d to the at- 

 ought, on this principle, to efcape as rapidly as under an ex- "^^'^^^'^j^^.^^j^"'"' 

 haufted receiver. It muft be remembered, however, that the vjcuum arifci 

 efcaping gas cojiftitules, by admixture with the'air of the at- ^/°'JJ']'^'Jj'^^*^jpjj 

 mofphere, a gas of diminifhed denfity, but flill of fuch denfitv of the fuperin- 

 as to retard the efcape of farther portions. All that the air-^^^^bcnt gas. 

 pump effefts is to remove thefe as fad as they ore liberated. 



There are various fa6ls, fatisfadorily explained on this doc Fafts explained 

 trine, which are irreconcilable to any former hypolhefis. Of J'^^JJj'^*"" 



thefe '' 



