412] 
A MEMOIR ON CUBIC SURFACES. 
407 
and we thus have 4M 1 + 3£iV = 0, 
LM + vf~N = 0, 
L 2 — 12 iv 2 M = 0, 
or, what is the same thing, 
L, 
12 M, 
-9X 
w'\ 
L, 
M 
for the equation of the cuspidal curve. Attending to the second and third equations, 
these. are quartics having in common w 2 = 0, L = 0, that is, the line y = 0, w = 0 four 
times; or the cuspidal curve is a partial intersection 4x4 — 4: c' = 12. 
Section VI = 12 - 5 3 - C,. 
Article Nos. 95 to 102. Equation WXZ + Y 2 Z + {a, b, c, d^X, F) 3 = 0.