1887. ] of the Quatermon Analysis. 169 
If we equate the different values for S.s,s,s,s,, we obtain 
sin(A, 5) sin(C, D) cos(AB, CD) 
= cos(C, A) cos(B, D) — cos(B, C) cos(A, D), 
and 
sin(B, C) sin(D, A) cos(BC, DA) 
= cos(C, A) cos(B, D) — cos(A, B) cos(C, D). 
St JoHn’s CoLLEGE, 
November 16, 1887. 
