The imaginary domains of conics and their interpretation in the complex plane
A 1912 mathematics thesis by Charles Richard Wilson on imaginary points of conic sections, submitted at the University of Illinois for readers of analytic geometry. The 26 plates are line diagrams in thin black and dashed rule: ellipses, hyperbolas, crossing asymptotes, labelled foci and axes, with hand-lettered equations and figure numbers usable as spare geometric ornament.
