206 THEORY OF NEWTONIAN FORCES. [FT. I. CH. V. 



These conditions are satisfied by the polar coordinate r for by 

 95, (4) 





For r = oo , we must have V=0, accordingly we must put B = 0. 



We may get a convenient expression for by transforming 



h q 



Ag into terms of three orthogonal coordinates, of which it is itself 

 one. Put q-qi, and since it is independent of q 2 and q s 



i_ 2s h, 



s 



109. Application to Elliptic Coordinates. Applying this 

 to elliptic coordinates gives 



I I ,(a 

 2 



c 2 +X 



