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IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This flat wooden blackboard curve has ...

Three marks along that edge indicate endpoints of axes of the ellipse. A mark on the bottom edge reads: HYPERBOLA. A mark at the center of the bottom edge indicates the turning point of the hyperbola.

This article was originally published with the title “Instrument for Drawing Ellipses and Hyperbolas” inSA Supplements Vol. 19 No. 490supp(May 1885), p.