IN THE NEIGHBOURHOOD OF A CAUSTIC. 

 These expressions correspond to the following quantities : 



395 



Equating the quantities on the middle line, or the sums of the 

 quantities next above and next below, 



a:'/. + A'"* 



ch' = 



12 



^' _ _ A" A"" 

 2 ^2 24 ' 



A!_* + A'» Alii + A'* /\'"'i + A'"" 



bh = -^ '- - (W = — ?- '- '-^ i . 



2 2 12 



Now the integral with res^^ect to ss of the function m,^^^ or 



u^ + Z»s + cs;^ + d'^ + e%\ 

 is 



* , c , c? , e , 



and this between the limits ^ = - - and :s = + - is 



2 2 



, A" , A"" - A"" , 

 = "-'''■^24''- 288^'-^ 1920^' 



, f A" 17. A"" 1 



= M"^^ 24-^76ri- 



This formula applies to the order of the calculations described above, 

 because we have computed the value of u, for the middle of each of 

 Vol. VI. Pakt III. 3E 



