434 , llemarks on Mixed Gases ^ 



because, a mixture of air and vapour in the 

 above circumstances is difFcrent in regard to 

 the law of elasticity from dry air ; namely, the 

 space is not inversely as th^ pressure. Mr. 

 Gough can make no difficulty of deciding this 

 point with his bottle ; for if he hold it with the 

 mouth downward in boiling water for a few 

 minutes, on cooling the water it will ascend so 

 as to fill the whole bottle nearly, and there 

 will not remain 4^ of the original air according 

 to Schmidt's table. 



From what has been said, it will appear that 

 \ consider Schmidt's table of the expansion of 

 mojst air as essentially wrong ; I would not, 

 however, be understood to depreciate the rest 

 of his work, which appears, from what I have 

 seen of it, to be very ingenious and valuable. 



I shall now conclude with a few observa- 

 tions on Mr. Gough's two Essays. — All the 

 abstruse investigation of the centre of gravity. 

 Sec. at page 299 and seq. is altogether su- 

 perfluous ; because every one must admit as a 

 tjeif-evident truth, the deduction from it at 

 page 301 . The observation commencing page 

 302 is a complete contradiction in terms; to 

 allow the particles of two dastic fluids to be 

 inelastic towards each other, at the same time 

 that given r(;//^W6'jr of such fluids are not so; seems 

 to be the same thing as allowing that the xvJiote 



