416 
PROFESSOR CAYLEY ON THE TRANSFORMATION 
+20 +8 -126+168 +196 -680 +239 +1072 -1240 -560 +1820-560 -1240+1072+239 -680 +196 +168 -126 +8 +20 -8 +1 =(v— 1 ) 8 (v 2 — 1 )*. 
