Complete set of cardboard models of second order surfaces in original packing by L. Brill of Darnstadt circa 1900
Set of 7 unassembled cardboard geometrical models in 4 packages showing surfaces of the second order on wooden stands [marked 1876-482]: (1) Ellipsoids having 22 sections, (2) Ellipsoids having 30 sections, (3) Hyperboloids of 2 sheets, (4) Hyperboloids of 1 sheet, (5) Paraboloids, (6) Hyperbolic Paraboloids, (7) Cones Set of 7 unassembled cardboard geometrical models 1901