84 



KANSAS UNIVERSITY QUARTERLY. 



ratios are not independent but are connected by a very simple 

 relation. Let p and p' (fig. 3 ) be a pair of corresponding lines in 



the plane; and let p cut the lines x, y, z in the points X, Y, Z re- 

 spectively; and let p' cut the same lines in X', Y', Z' respectively. 

 Since ^^(ABZZ'); kx^(BCXX'); and ky=(CAYY'); we have 



