A SYSTEM OF PARTICLES. 259 



equal to zero (20). The process is, in fact, manifestly insufficient in 

 that case. The objection, however, which there appHes, does not affect 

 the expression under consideration, as the latter consists of a single 

 term, whilst the former is the difference of two terms, in each of 

 which the principal part is the same. It is not impossible that some 

 of the omitted terms, even in the present case, should be considerable. 

 The first of these has been exhibited merely on account of the sym- 

 metry of its form. 



26. Recurring to the preceding expression for the pressure, and 

 taking as the limits » = 1, is = -, we get 



'■{a;' + f- + z')i 



h 



6 



{»'+r+ (j)}' (■'•+!''+i)'M«'+r + =•)•• 



" ^/(!r^^M?)' ^VnTTT; 



y ~ 1 e ■ ^ \e^" ^ 17/ , 7"*" ^ \7 ^V 



\/y=+ ^\ ^/r + 1 



ah 



2 



+ ' - 



m-^-*mv*m 



1 1 



2x. 



"'2(7TT7 ^'■^'^ ^ = 0' to^ = ^ 



Vol. VI. Par, II. Ll 



