136 
APOLLONIUS OF PERGA 
as particular cases of the new diameter of reference. The 
three sections, the parabola, hyperbola, and ellipse are made 
in the manner shown in the figures. In each case they pass 
through a straight line DE in the plane of the base which 
is at right angles to BG, the base of the axial triangle, or 
to BG produced. The diameter PM is in the case of the