ATTRACTION. 8PHEI:: KLL. !!*."< 



therefore ( 



t ia introduced merely as an analytical artifice to 



222. To find the aUractim of tfo*W o*a* internal par- 



ti '. 



rah ulntion is the same as in the In >, except 



that the limits of y are r c and r + c. Hence, the attrac- 

 of the shell 



:")rmula3 -\vo Articles will give 



;i the law of attraction is kno 



*W-; U AW 



A and /? being constants. 



ton- tin- attraction on an external par 



