240 Of the SOLIDS 



ment of the attraction of the folid. If that attraction = F, 

 then F =z (<p x. But f<p x — <px — fx p ; and the determi- 

 nation of F depends, therefore, on the integration of * <p. 



Now <p cof <p z=. fin <p, and, therefore, x $ zz — —-, 

 If B'G = b, and B'H = p, then fm B'AG = -JL. = 



AG ■ " V^+p' 



and fin BAH - JL- = — J ; fo that finp= 5 X 



AH yp« + *. Vp+~p 



p , T — i **£* 



, and im<z> rz ttt-t — *\ //M , *« 



7 2 r>z 



Hence, cof q>' ~ i — fin <z>* n i 





(£ 2 + O(0 2 + O 



Again, becaufe fin <p zz . . — ^ fin<p 



Vz>* + * 2 Vp* + * 4 (£* + <) 



x P , £** x— -i 



(F + O t (P 2 + ^) T (^+^ 2 )' 



fin <z> 



Hence — ^ or <p = 



coi <p 



x —b$xx £j3at* x 



