58 Sill G. GREENHILL ON ELECTED MAGNETIC INTEGRALS. 



17. The P.F. of the solid cylinder is given by 



in which 



(2) 



(3) 



(4) ^-Qbdb = J[Q(MQ)-2,r]&d& 



cosd + a'tfdddb 

 MQ" PQ 



, 



bringing in again the same intractable integral I. 

 We obtain V otherwise from the integration of 



. =' 



As a verification we have to prove by differentiation that 



/ 6 \ 



27rA dA db 

 implied in the integration of (l), 15, and 



(7) r= 



implied in-(4), 16, the expression of the rim S.F. of the circle AB. 



And for the P.F. W and its S.F. 



da 



(8) 



- J 

 da db 



(9) 



da dA 



18. An integration of L in (6), 2, with respect to b will give the S.F. of the solid 

 cylinder 



(1) N 



