QG 



PROCEEDINGS OF THE AMERICAN ACADEMY 



in which all the constituents are zero except those in the squares along 

 the principal diagonal, and 



Vi = 



the a's, 5's, c"s, etc. being arbitrary ; the mode of filling up the re- 

 maining squares along the principal diagonal and the rectangles above 

 the principal diagonal is obvious. A similar expression obtains for 

 r}2, etc. 



WoECESTEB, May 26, 1891. 



