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ON THE CLASSIFICATION OF CUBIC CURVES.
367
totes ; and each of these according as the asymptotes form a triangle or meet in a
point ; that is, according as the asymptote-point does not, or does, lie on the real
asymptote.
The Parabolic Hyperbolas are distinguished according as the asymptote is ordinary
and the asymptotic parabola one of five-pointic intersection ; or, as the asymptote is
osculating and the parabola one of six-pointic intersection ; and each of these according
as the asymptote cuts, touches, or does not cut, the parabola. The Hyperbolisms are
distinguished into those of the hyperbola, ellipse, and parabola, and each of these
according as the asymptote is ordinary or osculating. The Divergent Parabolas are
distinguished in the manner already mentioned; viz. according as the curve is the
semicubical parabola ; or, as there is a satellite line not at infinity, and an asymptotic
semicubical parabola of seven-pointic intersection, and which is cut, touched, or not
cut, by the satellite line ; or, as the satellite line is at infinity, and the semicubical
parabola is of nine-pointic intersection. The Trident Curve and the Cubical Parabola are
not divided.
49. I annex the following Table showing the Groups included in each division :
for shortness I use the before-mentioned symbols A, © to denote that the asymptotes
form a triangle or meet in a point respectively.
Table of the Plückerian Divisions.
Hyperbolas :
Redundant ;
No osculating asymptote,
A i, ii, hi, iv, v, vi
© VII, VIII
One osculating asymptote,
A ix, x, xi, xii, xiii, xiv
© xv
Three osculating asymptotes,
A xvi
© XVII
Defective ;
No osculating asymptote,
A XVIII, XIX, XX, XXI, XXII, XXIII
© XXIV, XXV, XXVI, XXVII
Real osculating asymptote,
A XXVIII, XXIX, XXX, XXXI, XXXII, XXXIII
© XXXIV