478 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



fourth, terms in descending powers of s from s v ~ k ' down. Our scheme is 

 then the following : — 



(M 



+ 



I 



CO 



CM 

 + 

 1 * 



1 „* I 



co S ec 

 O O 



Co "■© 



© 



CO 



o 



5. 

 e 



i 



co 



+ 



c 



f 



5s 



4 

 co 



I 



a. 



CO 



rH 

 + 



I 



co 



4 

 co 



«0 



O 



-. »o 



4 

 co 



co ~0 



CO 



■Ai 



i 

 CO 



&> 



Si 

 I 

 CO 



O 



4 

 CO 



^ 



4 



CO 



4 

 CO 



CO CO 



Looking for terms of highest degree in s and lowest degree in x, y, and 

 z, we first take v — 1 constituents diagonally, beginning with the first 



