298 CONSTITUTION OF MIXED GASES. 



nuoufly than myfelf. Subfequent attention, however, to the 

 evidences of the theory, and ftill more the refults of experi- 

 ments which were made under irapreffions very unfavourable 

 to the hypothefis, have fatisfied me that the oppofition to it 

 arofe chiefly from an imperfedcomprehenfion of the argument; 

 and that your theory is far better adapted than any former one, 

 for explaining the relation of mixed gafes to each other, and 

 efpecially the conne6tion between gafes and water. 

 Diftingulfhing The diftinguifliing principle of your do6trine I apprehend 

 mt^n'l theor *° ^^' ^^^^ mixed gafes neither attraa nor repel each other, and 

 that exery gas is as a vacuum to everi^ other gas. It is not my 

 intention to recapitulate your proofs of this pofition, but merely 

 to add to them the evidence of a few fa6ls, which have occur- 

 red to me, and which ftrongly tend to eftablifh the fame con* 

 clufion. 

 Since gafes are From a feries of experiments, which I communicated to 

 'aJwa'"sWcha. ^^^^ ^°>'^' Society, and which appeared in their Tranfaalons 

 nicaily in quan- for 1803, it may, I think, be fafely inferred, that the relation 

 ''^'^ ^^ ^fiV of gafes to water is altogether a mechanical one; for the cjuan- 

 ent gates do not tity abforbed follows exadly the ratio of the prefTure. If then 

 prefs each other j^ f,^^ [jg fhewn that a gas, abforbed by water, is not retained 



if they do not ■ -, , , r i r .< n n i 



prevent efcape. '" '^^ place by an atmolphere of any other gas, we ihall be 



furnitlied with a ftrong prefumption that different gafes do not 



gravitate on each other. 



Carbonic acid It is well known that water may be charged with its own 



^"fed'to Ae^at- ^"'^» ^r rather more, of carbonic acid gas, under a prelTure 



mofphere, of 30 inches of mercury. The gas, thus abforbed, is retained 



fo long as the water is preferved from contact with any other 



gas; but, when expofed to the atmofphere, the carbonic acid 



— becaufe at- gas rapidly efcapes. Now this efFe6t can be only afcribed to 



beaufe'not^ ^ ^"^ °^ ^^^ caufes, ift, the affinity of carbonic acid for atmof- 



preffed by the plieric air may furpafs that of its affinity for water; or, 2dly, 



atmofphere. ^j^g ^jj, ^f ^j^g atmofphere does not prefs on the gas in the 



water, which is therefore placed under fimilar circumfljinces., 



as if expofed under the exhaufted receiver of an air-pump. 



Not from at- Were the 6rft explanation the true one, it might be expected 



traction; for ^j^^j^ equal quantities of various gafes would detach different 



different gas quantities of carbonic acid from like volumes of impregnated 



caufe no differ- vvater; becaufe the affinities of thefe gafes, as in all other cafes 



of chemical affinity, differing in force, would occafion their 



combining with different quantities of carbonic acid, and in a. 



pertain 



