S70 OUTLINES OF NATURAL PHILOSOPHY. 



. Now the Sun, by the united action of the planets P 

 and P', is drawn in the direction opposite to this 



- m x m r a/ 



Jast by a force = -75- -f 7 , and as the Sun is 



here considered as immoveable, we must conceive 

 this force to be transferred to P in the opposite 

 direction* 



Thus the whole action on P, or the force F = 



x m x , m' x' , m' q 

 - 3 H T> 7* f ^7J 



__ (1 + m) x , m' x ? m' q 



~~ ar " 



By writing in this formula j/, y r andj/, instead of x> 



+ 

 and in like manner 



x> andi, we have F = + ? 



m' z f m'q 



-- Ji i -- ~ 



r J 



The substitution of these values of F, &c. in the 

 three formulas of the last article, will give three 

 fluxionary equations, on which the motion of P 

 depends. 



The same being done for P', there will come out six 

 fluxionary equations, from the integration of 



which 



