COFFIN. — EDOE CORRECTIONS IN CONDENSERS. 433 



From which, given any value of A' which determines the configuration of 

 tlie polygon, we can find m by the formula 



m = 1 + A' ± ^K{K +2), 

 and vice versa. 



The diagram in the w-plane consists of two parallel straight lines, the 

 angle being zero, and the value of t corresponding being t = -\- \. 

 Hence 



dw dt 



w = (j) -\- i if/ = B[\og {t — I) -\- const.]. 



Const. = 0, because xj/ = as long as « > 1. When t passes through 



the value < = 1 and becomes less than 



^' ~ '^ Z °° unity, ip increases by v = Bir. 



t = +\ 



V = + CO y 



Hence B = -. 



IT 



Now the quantity of electricity on a strip of breadth x and depth unity 

 is by the general equation : 



V 



and since w ^= ~ log {t — 1), 



TT 



'.[log(^-l)-log(-l)] 



77 



4_-2 



= 7^.1og(l-0, (0) 



'i IT 



which gives the amount of electricity on a strip of breadth x, on the 

 under side of the upper plate from the corner B, to a point P at a dis- 

 tance — X, from B. 



Let us now find a value of log (t. — \) so far from the edge and on 

 the lower surface of the upper plate that t may be considered nearly 

 equal to unity, say ^ = 1 — c. From (a) 

 VOL. XXXIX — 28 



