II. Note on Mr. Russell’s paper ‘On certain geometrical theorems. No. 2.'

Abstract

If we apply Mr. Russell’s formulæ to the determination of the sextactic points of a curve, we shall have, in addition to the equations (1)—(5), the following — α D 5 y + β D 5 ( xy ) = D 5 y 2 and by elimination of α and β from his equations (4) and (5), together with this latter, we shall obtain as the condition for a sextactic point- D 3 y , D 3 xy , D 3 y 2 = 0. . . . . (A).