PREFACE TO PART II. XV 



He then proves that if 



i cl m P 



'" - " 



~~ 



P 0Q-f/-( n + m ) ! P 



J _! ^ ^' ^ - (^^) ! J _! 



Hence if n and ^ are not equal 



1 -1 



But if n l = n, then 



n 





Hence if 



n'" = V LL O m nnrl TT m 

 n / rT I ^n dJlQ 1A,,_ 



it follows that 



r 1 



n;; ! n( 

 J-i 



and, when n = n 1 , we have 



It is also shewn that 



And therefore, when n and ^ are not equal, we have 



and, when n, = n, we have 



