672 Mr. A. A. Robb on the Conduction of Electricity 



is equal to 1 — e , ,— -1 . , 

 ■ cosh 1-6 a) sinn 



I da> 



J cosh 1-e 



W l-2e 



0) 



(14) 



Writing as before cosho)=p~^ we get for tbe value of tbe 

 series when g) = 0, 



J o cosh l ~* « J 



■Of) 



\2(l-e) + 2/ 



A similar result may be readily obtained for tbe value of 

 e greater than J. We have thus got all the formulas necessary 

 for calculating the tables. £t is desirable, however, that the 

 integrals which go to make up v or x should be tabulated 

 with the lower limit zero, as in this way we get x at once 

 measured from one of the plates, and have therefore no 

 trouble with the second constant of integration k 2 . Thus, 



putting for e the value - corresponding to ^- 2 = - , we have 



s the solution of (1) 



(15) 



in which 



4 i 

 9 eq 



R + ^ 



2' 6 \3 39 cosh 6 a) 



+♦}■ 



cosh* o> 



1 f 14 1 1 14x24 J_ 1 



2 \l9cosh 2 o> 2 19x29cosh 4 a> + /* 



= T l cosh* G> G?ft> 



_i r(-i)rc5) ', 5 i jr; 1 9 1.3 _9____ 1 



~2 r(-6)" + 4 C0Stl W l 1 ~2c'o^h^~2^2 11cosh 4 a> J 



