350] 
ON THE CLASSIFICATION OF CUBIC CURVES. 
399 
Newton’s Genus 10, contains 3 Species, viz. 
61 62 63 
corresponding to Plticker’s Species 
LI. 
201 
LII. 
202 
Newton’s Genus 11, contains 2 Species, viz. 
64 65 
corresponding to Pliicker’s Species 
LI1I. 
203 
LIV. 
204 
Newton’s Genus 12, contains 1 Species, viz. 
66 
corresponding to Plticker’s Species 
LX. 
Newton’s Genus 13, contains 5 Species, viz. 
67 68 69 70 71 
corresponding to Pliicker’s Species 
LV. 
205 
LVI. 
208 
207 
206, 209 
LVII. 
212 
211 
210, 213 
LVI II. 
214 
215 
LIX. 
216, 217 
Newton’s Genus 14, contains 1 Species, viz. 
72 
corresponding to Plticker’s Species 
LXI. 
It is to be noticed that (as appears by the Table) Plucker enumerates 13 species 
of the Divergent Parabola, viz. corresponding to the Parabola Pura of Newton we have 
five species, and to the Parabola cum Ovali three species; but to each of the other 
three Newtonian species (Nodata, Punctata, Cuspidata) only a single species. The 
difference in nowise affects Newton’s before-mentioned theorem, that every cubic curve 
is the shadow of a Divergent Parabola; but (the characters of Plucker’s species being 
unaffected by projection) the number of resulting kinds of cubic curves (or cones) will 
be five or thirteen according as the one or the other classification is adopted; but 
this is a subject which I do not enter upon in the present Memoir. 
Cambridge, February 8, 1864.