DEDUCED FBOM THAT Of A PARTICLE. 



: nolrcular act ion t an 

 represent the 



resolved part parallel t-. the axis of x of any one of the 

 molecular forces involved in the Sit equations, we shall 

 wise meet with the term - /'cos a, in another of those equa- 



ivc reference to the axis of x. Conseqn< 

 if we add all those equations together which hare reference 

 M same axis, we hare the three following equations of 



v-o, sr-o, 



second consideration i* nt the itrni^ht line* 



c different particles are the directions in v. 



mol cs act. 



molecular action between the fwrtielet 

 whose cc-ordinatet are (u,, y, , s t ) and (a^, jf t> ,), 



P.cosa,, cos/9,, 



>rrcsponding resolved parts ot /', for the two particles. 



" 



-, 00.7,- 



wh. r - 



These enable us to - more equations free from 



r forces; for if we multiply (I) and (2) by y, and jr t 

 vely, and tin n subtract, we hare 



f ... + 1\ ^cos/9, -y.coaoj + ...-0... (4). 



he same process we obtain from the system of equations 

 to the particle (,. y t ,O, 



*>.- 



3 of cos o, and coa t given above lead to the 



