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This object consists of many metal rods and bars attached together. It is supported on three legs with masking tape wrapped around each foot. On one leg there is a wooden tear-drop shaped knob which is attached by a part-U-shaped rod. Attached to this there is a mechanism in which two separate carriages can slide along metal rods when a handle is turned. This mechanism ends in an adjustable grip which could hold a short drawing tool, like a graphite lead. The mechanism has a graduated rod long which the parts can be slid to enable adjustment of the instrument.

Accession Number: 2018.ast.82

Alternative Name: Drawing Instrument, Drafting Instrument

Primary Materials: Metal: Iron Alloy, Wood


On the graduated rod: “0” “1”

Underneath the instrument, engraved: “7”

Dimensions (cm): Length = 25, Width = 18, Height = 14.25


This in an instrument for mechanically drawing ellipses.


Fair: The metallic surfaces of this instrument are corroded. Where the instrument was lubricated to permit movement there is residue left and the moveable parts have seized up. There are wear marks along these parts. The tape at the base of the legs has likely been added sometime during the use of this object. This tape is now brittle and coming away in some parts.

Associated Instruments:


Date of Manufacture:


This object was likely moved from the David Dunlap Observatory in Richmond Hill in 2008, upon the sale of the observatory. It was stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.

Additional Information and References:

Examples of ellipsographs and other similar instruments can be found at <a href=></a>. Accessed October 15, 2018.

Historical Notes: