ATTRACTION. SPHERICAL SHELL. 



Hence the resultai whole shell 



renult shews that the shell attracts the particle at /' in 

 the same manner M if the matt of the shell were condensed 



212. I- Hows from the prece i that a sphere 



' ntogeneoits or consists of concentric spheri- 



cal shells of U: at /' i 



tame manner as if the whole mass were collected at its centre. 



r+find 4* attraction of a Homogeneous tpker^d shell 

 of small thick-net* on a par tick placed K\ n it. 



i nust proceed as in A limits of y arc in 



this case r c and r + c ; hence the resultant attraction 



fore a particle within the shell is equally attracted in 

 y direction. , 



Suppose a parti < a homogeneous sphere at the dis- 



tance r from its centre ; then by what has just been shewn all 

 that ]xmion of the sphere which is at a greater distance from 

 the* produces no efiV 



Also by A.-. Jll, the remain: >c sphere attracts the 



particle in the sain.- manner as if the mass of the reran 

 were all collected at the centre of the sphere. Thus if p be 

 the density of the sphere the attract Ic is 



t**u& a homognieous tpJttr* the attraction eoriVt at ike 

 distance from ike centre. 



L The propositions respecting the attraction of a uni- 

 :i an external mal particle were 



