THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL. 



Sl'f O C TO BEE 1825. 



XXXIII. On the Constitution of the Atmosphere. Bj/ J. Ivory, 

 Esq. M.A. F.R.S. 



[Continued from p. 93.] 



5. XT' appears from what has been said in this Journal for 

 ■■■ August last, that when a mass of air rises upwards in 

 the atmosphere, the heat absorbed by the rarefaction is greater 

 than the loss of temperature. In the course of its ascent it 

 receives heat from the contiguous fluid, which in part balances 

 what disappeai's on account of the continual dilatation. But 

 although the loss of temperature is thus reduced below the 

 heat that enters into combination in a latent form ; yet both 

 these quantities increase together, and hence arises the degree 

 of cold that is found to prevail in ascending above the earth's 

 surface. 



The heat absorbed in rising to any height x, and the whole 

 extraneous heat received, being denoted as before by i and 5, 

 and the loss of temperature by /, v,e shall have 



i — ^ — t\ 

 And this value being substituted in the equations (F), we shall 



get / \ -\-a.T- ai \^ l + ".r-a.t 



p = (-1—.-^) 



1 + 



=(- 



1 + ZZ / * 



In these equations t is the temperature at the earth's sur- 

 face, g the density and ]) the elasticity at the height .rv The 

 atmosphere being in equilibrio, the pressure is equal to p ; and 

 the quantities p, i, t vary together, since they all depend upon 

 X. We therefore get by taking the fluxions, 



But we likewise obtain fi-om the equation (H), 



d]> ■ di- 



- -— -as - ,^,^„,)- 

 Vol. 6G. No. 330. Oct. 1825. H h Where- 



