8*S Affinity of the Element* of Atmospheric Air, 



thing more, therefore, can be inferred from the facts above 

 mentioned, than that gravity overpowers, and for a mo- 

 ment obliterates, the effect of that cause, which in other 

 cases slowly produces the dispersion of the fluid, whether 

 it be attraction, as is commonly supposed, or repulsion, as 

 I suppose. Chemical philosophers have not inquired sum- 

 mit ntlv into the effects of exposing gases in different circum- 

 stances to the atmosphere : all that we are usually told is, 

 that a jar filled with hydrogen, and uncovered, loses its gas 

 in a few seconds ; but, if inverted, it remains nearly pure for 

 a considerable time, &x. I find that a cylindric jar of 7 

 inches depth, and 2^ diameter, being filled with hydrogen, 

 and inverted, loses more than half of its gas in two mi- 

 nutes; and there is so little left as scarely to explode in five 

 minutes. If a tube 12 inches long, and J inch in diameter, 

 be filled with hydrogen, and exposed in like manner to the 

 atmosphere, it will lose half its gas in five minutes; and 

 that the same, whether it is held up, or down, or horizontal. 

 Here we see effects that cannot be caused by gravity, that 

 are produced in opposition to its agency, and where, in- 

 deed, it is almost obliterated by the action of some more 

 powerful cause. Let the advocates for the atmosphere being 

 a chemical compound attend to such facts as these, and 

 thev will soon find themselves reduced to acknowledge that 

 all gases have the same affinity for one another, a position 

 which their doctrine ultimately tends to establish. Indeed, 

 it is the same with regard to air, and vapour of water, aether, 

 or any other kind; that is, all kinds of gas, or mixtures of 

 gases, have the same affinity for the same vapour; and even 

 a torricellian vacuum possesses just the same affinity as any 

 of them, judging from the quantity evaporated and force 

 of the vapour in a given volume. If any one doubt it, he 

 may easily satisfy himself by throwing up a drop or two of 

 aether into the vacuum of a common barometer ; if the tem- 

 perature be 0S°, the mercury will fall 15 inches nearly : at 

 the same time, if a'ther be admitted to a given bulk or" any 

 kind of gas, subject to the pressure of the atmosphere, its 

 volume will be doubled ; clearly showing that the elastic 

 vapour from the mber is the same in both cases, namely, 

 an independent fluid of 15 inches force. 



I cannot di.smi.ss this subject without observing, injustice 

 to Dr. Thomson, that lie has entered more clearly into my 

 views of these subjects than any other of our own country who 

 bus animadverted upon them. There are certain principles, 

 however, which he, with most chemists of the present day, 



embraces, 



