262 Mr KELLAND, ON THE MOTION OF 



of two immaterial particles at those points, respectively ; then, for the 

 equilibrium of a small portion of air between them, if p, p be the 

 units of pressure ; we have 



pr' p'r'- c r^dr , ■, . , , ... 



^-5- = ^-r, -J • — 3— (c being due to gravity), 



jS 



6 



d.K 



e- C 



or — , — = — 

 dr e' 



, d.pr- „ „ de 



hence e . — i 2pr- . -p- = c . 



dr ^ dr 



Let 6 = Ar" + 



tlien p is the force upwards produced by the coating of atmosphere, 

 diminished by that of gravity acting downwards, and 



« 1 /•! o 



r' /•' J.A'p" 



P 

 1 



r* ^V»- 



+ ... 



Now if M = 2 this is -7 , also if w = 1 the same form is true ; 



assume therefore 



P=^i ••■P>^=«, 



, d pr^ c , 



hence t- ^-— = —^ becomes 

 dr e' £ 



d a _ c 



dr '= 



also e = Ar + B. 



