250 PEOFESSOE CAYLEY ON CUBIC SUEFACES. 
(1(1-^-^-*)-^ -^=0, 
[25'=p,] 
[15.23.46 = qi ] 
1+7-*? z -*"“(;( 1 -i-s>)(J’-“J-a),wi= 0 * 
[53'=rj] 
— ' ^-^X+wY+mZ— j;bWl— m2— *) — 2j»«)”p=0, 
[61'=pj] 
« x - £ T ! Y+®-A.( ffl (l-»>-P)(^- K )-2«0^ ? =0. 
[36'=q,] 
[13.26.45=5] 
43. The coordinates of the 27 lines are then found to be as follows : — 
1 
(a) 
m 
(c) 
1 
0 
0 
0 
1 
0 
0 
0 
1 
i-B 
(-=>K) 
-u 
H)H) 
-JH)H 
-u 
1 
' J -7)("-=) 
1-il 
V J V \ ”7 
-s*( m -s)( n -s) 
-b 
R)H 
-b 
H)K) 
-i( Z -7) ( m -s) 
l 
0 
0 
0 
1 
0 
0 
1 
0 
i 
