210 ON THE DETERMINATION OF THE ATTRACTIONS 



all the finite integrals being taken from rltor = s+l 9 and 

 from/ = l to/ = 5 + l. 



In order to obtain the required value 



it is clear that we shall only have to add the first of the five 

 preceding quantities to the sum of the four following ones multi- 

 plied by h'j and to render this more easy, we have appended to 

 each of the terms in the preceding quantities a number inclosed 

 in a small parenthesis. 



Now since the accents may be permuted at will, and we 

 have likewise a 2 = V + h?, it is easy to see that the terms marked 

 (1), (6) and (12) mutually destroy each other. In like manner, 

 (2), (3), (7) and (18) mutually destroy each other; the same may 

 evidently be said of (13) and (16), of (15) and (17), of (9) and 

 (19), and of (8) and (14). Moreover, the four quantities (4), (5), 

 (10) and (11) will do so likewise, and consequently, we have 



Hence the truth of the equation (31) is manifest. 



