CONSTITUTION OF MIXED GASES. J^J 



- Second, If the latter alternative fliould be preferred, the An experiment 

 rollowing experiment, with which Mr. D. is already ac- ^'^jj^* ''^' 

 iquainted, remains to be explained by the principles of his 

 hypothefis, due attention being at the fame time paid to the 

 axioms of Dynamics. 



A moid bottle, which I had found would contain 7794 

 grains of water of the temperature of 59**, was placed in 

 water heated to 126°, having its mouth elevated about two 

 inches above the furface. This aperture was covered by my 

 hand ; which was occafionally removed for an inftant, that the - 

 warm air might efcape. At the end of two minutes the bottle 

 was inverted in cold water, the mouth of it being firft fecured 

 in the manner defcribed above ; in which fituation the tem- 

 perature of it was again reduced to 59**. The air remaining 

 in it after refrigeration, occupied 6172 of the 7794 parts con^ 

 ftituting the capacity of the bottle. From this fad I infer, 

 that 6172 parts of air of 59^, will occupy *7794< fuch parts 

 after being raifed to 126'* in contact with moift glafs. But 

 6172 parts of dry air of 59®, will only occupy 6992. C6 parts» 

 after being heated to 126® in a dry tube; Thus it appears 

 that the prefence of water augmented the bulk of the air 

 which I ufed; how is this difficulty to be explained i We 

 have no ftopple of mercury in this experiment, by help of 

 which Mr. D, explains the appearances of the manometer; 

 confequently, as nothing was in the way to prevent the free 

 egrefs of the vapour, it expanded itfelf in the bottle, and 

 aded on the air contained in the fame, juft as it does in the 

 atmofphere. But it increafed the bulk of this air, which could 

 not be effeded on Mr. D.'s prirvciples, otherwife than by dif- 

 tending the pores of it. Now his own tables of the force of 

 vapour will (liew this to be impradicable, if there be any truth 

 in the axioms of Dynamics. On the contrary, nothing oc- 

 curs in the two laft experiments repugnant to chemical union ; 

 and as water makes a part of the atmofphere, it muft be at- / 



tached to air by the rnediation of affinity. 



I have now done fomething more than anfwer all Mr. RecapItulaUop; 

 Dalton*s objedions : the demonftration of his fundamental 

 propolition has been (hewn to be no demonftration at ail ; his 

 fecond populate has been proved to be falfe, by his own data^ 

 in the cafe of air and vapour ; laftly, two fad^ have been 

 advanced which are inexplicable by my opponent's prin- 

 M2 cipit 



les; 



