R ?l a R" +1 /a\ 2 R ,! + 2 r2w + l 1.3 



— cos ny-\ — . — rr cos n — 1y + — zt- \ i °os «%H 



a n A 2c a w + l \2c a n+i \ 2 2n + 2 A 2 . 4 



, . p — 1 1.3 (2ra + l) (2n + 2p — 5) .. N 



cos (ti + p-2)v+ / - ) — { t ^cos (n+p—4)x 



V JX-r 1 2 4 ( 2n + 2 j (2^ + 2^ — 4) V r JA - 



(p-l)(p-2) 1.3.5 (2W. + 1) .. .. (2n + 2p-7) 



+ — • • 7 cor (rc + p — 6)v 



2\ 2.4.6 (2n+2) (2rc + 2p — 6) v r yA 



+ 



... }+ & 



is a solution of Laplace's equation. 



A similar expression holds when for cosines we write sines. 

 Writing now 



a = - and L == lot? — j 

 c ° a 



the potential of a solid anchor ring at internal points is found as far 

 as terms in o- 4 . As far as terms in a 2 it is given by 



The work done in collecting the ring from infinity is 

 2ttc L 4 8 512 J 



