Signedengraved in script on ellipsograph arm: J. H. Temple Boston
FunctionEllipsographs are mechanical, analogue instruments used to draw ellipses of desired specifications on the surface below. Users place a writing surface beneath the ellipsograph and insert a writing implement in the holder. Manually turning the brass crank indirectly imparts the necessary horizontal and rotational motion mechanical motion for drawing ellipses.
The general principles behind ellipsographs is outlined in W.F. Stanley's book, Mathematical Drawing and Measuring Instruments, available from Google books here. Chapter X concerns the mechanical drawing of ellipses and the ellipsograph.
ProvenanceTransferred to CHSI, From Agassiz Station, 20 June 1969.
Related WorksGerard L'E. Turner, Nineteenth-Century Scientific Instruments (Berkeley, CA: University of California Press, 1983), pp. 76-77.