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Chart Recorder


This instrument is affixed to a four-footed wooden base and covered with a glass box framed in wood. Underneath the glass, which can be lifted off, there is a metal cylinder with a knob on the top. This can be lifted off to reveal a large metal gear attached to the base and a small gear attached the the cylinder. Visible inside the cylinder there is a clockwork mechanism. This can be wound to turn the cylinder slowly. Around this cylinder there is wound a short strip of chart paper.

On the other side of there is a vertical rod which supports a thin strip of metal with a pen nib at the end. This reaches out to rest gently against the chart paper around the cylinder. A set of arms, both strips and rods of metal, supported by this main rod can alter the orientation of this strip, raising and lowering it. This is adjusted by a knob mounted on the base.

Also set in the base, there is a vertical arm that can be swung around to lift the pen nib off the chart paper. Next to this, there is an ink well labelled “INK”. Inside this there is an ink-stained metal piece like a small spatula that can be used to drop ink into the pen.

Accession Number: 2019.ast.172

Alternative Name: Thermograph

Primary Materials:

Wood, Metal: Iron Alloy, Metal: Copper Alloy, Metal: Other (?), Paper


On a metal label affixed to the base: “Taylor Instrument Companies

Around the ink well: “INK”

Around the knob which raises and lowers the drawing arm: “PEN DOWN – UP”

Printed around the base of the chart paper: “VARIAN ASSOCIATES OF CANADA LTD. – GEORGETOWN ONTARIO”

Dimensions (cm):

Length = 34.1, Width = 19.2, Height = 12.6


This instrument harnesses the regular expansion and contracting properties of metal to measure and record changes in temperature. As the metal expands in warmer temperatures, the arm is lowered on the paper. When the cylindrical section is wound up to rotate, the line drawn on the chart paper indicates changes in temperature.


Good: The instrument is dirty and dusty, but the surfaces are in good condition. The metal of the cylinder is dulled and corroded in places; the other metal components are in good condition. It is not clear if the clockwork of the cylinder still functions. There is a large quantity of caked blue or black ink on the ink dropper, and some on the pen nib. The paper currently wrapped around the cylinder is not likely to be original.

Associated Instruments:


Taylor Instrument Companies, Rochester, N.Y.

Date of Manufacture: Early 20th Century; after 1905


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:

Historical Notes: