CONICS
, that part of the higher geometry, or geometry of curves, which considers the cone, and the several curve lines arising from the sections of it.
CONJUGATE Axis, or Diameter, in the Conic Sections, is the axis, or a diameter parallel to a tangent to the curve at the vertex of another axis, or diameter, to which that is a conjugate. Indeed the two are mutually conjugates to each other, and each is parallel to the tangent at the vertex of the other.
Conjugate Hyperbolas, also called Adjacent Hyperbolas, are such as have the same axes, but in the contrary order, the first or principal axis of the one being the 2d axis of the other, and the 2d axis of the former, the 1st axis of the latter. See art. 17 of Conic SECTIONS.