a V 8 ATISHIES. 



For since r - {(* - a) f -I- (y - *)' + (* - c) 1 )*, 



,i </ /1\ y-6 d t\\ *-c 



J-^T"' eMJ- V' i W ""?" 



/IN Sfc-o)* 1 

 (r)' ^ ?' 





<r m a (* - c)* i 



r) m "7 7 



S-///56)'*** 



hold for 



and ,, ; therefore 



,, T ,, 



>W 

 ami <imil:ir 



holds so long as the attracted particle is not in 

 contact with the attracting mass. If, however, the attracted 

 particle is in contact with the attracting mass, r can vanish, 



fore - and its differential coefficients become injuub; 

 receding demonstration does not hold in this case. 



239. At .in internal point (a, b t c) about wkic* fa density 

 is p, the function V satisjus fa equation 



in this 



n 





(/' r 



To determine the yalue of ^ -h 



