84 ROYAL SOCIETY OF CANADA 
€,— @s , : 
D 2, 18 equal to one of the cross-ratios of the roots of 
ie ee 

The quantity 
4 23 — g,z—gs = 0, considered as a biquadratic with an infinite root. If 
we introduce Jacobi’s elliptic functions ; Jordan, Cours d’Analyse, vol. 
II., p. 401, we find 
Ex— CA 2 . a 
eae k?, which is the modulus squared. 
1 oO 
Hence the results enunciated as Theorem 3. 
