Conversely, If a cone be such that its tangent If a cone be such that the planes plane, passing through any side, in- passing through two fixed axes and tersects two fixed planes in two through any side whatever, make right lines, making equalanbsp;...
|Title||:||Two geometrical memoirs of the general properties of cones of the second degree, and on the spherical conics, tr. with notes and additions by C. Graves|
|Author||:||Michel Chasles, Charles Graves (bp. of Limerick, Ardfert and Aghadoe.)|