Convection Currents in the Atmospliere. 117 



will be approximately uniform. At any instant, then, the 



greater part of the plane will be very nearly at one of two 



particular temperatures. In rinding these, we can neglect 

 ps2y 



s— 5-. In particular, consider the conditions over the land. 

 In the earth we get 



and in the air 



r 



V 2 = A 2 exp^--^'^/^) ex P^ 



Q-t-x<£> 



(10) 



+ — r-13— «"**+ 1 i. e ~ vz - c 11 ) 



— k 2 k -\-i>y —K 2 \> z -\-iy 



As V = <l> when 2 = 0, we have 



A e f *'=G>, (12) 



T.-*»H?j\/£') <> 3 > 



**" , '(-^V|') («) 



Further, the equation of transference of heat across the 

 bounding surface gives 



K 2 P /! + * Ay_ \ 



The value of 3> thus found must be substituted in the 

 formulas for V and V 2 . 



