On the Height of Mountains, Headlands, fye. 



17 



T 



1! 





 C 



LB 



place, V the pressure at any other place, and D' its corresponding 

 density, we shall have P : D : ; P' : D / ; that is, the pressure is to 

 the density in a constant ratio, and may be represented by n : 1 ; 



.\P :D::F ity:\n : 1. 



Consequently, D=^P, 



D 



1 P / 



xp// 





&c. 



That is, the density at any place is equal to, or may be measured 

 by the ~th of the pressure of the column of the atmosphere above 

 that place, or by the ^th of the compressing force. 



Hence, if we make P stand for the pressure at the surface A, 

 and let each of the parts AB, BC, CD, &c. be equal 1, then will 

 ~V represent the weight or pressure of the part AB ; and 



• • 



p 



I 



n 



P 



n-1 



n 



P=the pressure at B, 



and 



n 



1 



n 



P=the density or weight of BC. 



In the same way, 



n 2 

 (n-1) 



P=the pressure at C, 



n 



P=the pressure at D, &c. &c. 



So that the pressure, and consequently the density, will decrease 

 in a geometrical progression, as the altitudes increase in an arith- 

 metical progression. 



Calling the density at the surface d n 1 and the several altitudes 

 1, 2, 3, 4, &c, we shall have the following corresponding series- 



Altitudes, 



o, 



1, 



2, 



3, 



4, 



5, &c. 



Corresponding densities, d n , d"- 1 , d n ~ 2 , d n ~ 3 , d n ~*, d n - 5 , &c. 



Vol. iliv, No. 1 .— Oct.-Dcc. 1842. 3 



