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Mirror Galvanometer (H. Tinsley & Co.)


A wooden box-like instrument with a rounded front. he front of the box has a scale, printed on a translucent material, that runs 5-0-5 and a company logo stamped on a metal plate. At the rear of the instrument are two electrical leads, an electrical cord, and a metal information tag. `The top of the instrument consists of the hinged lid that can is secured in place using two captive screws. Diagonally across the lid is a label of blue embossed tape that reads: “Wheatstone Bridge Galvo–J.M. Perz”.

Opening the box reveals the interior consisting of a metal galvanometer mechanism, It also includes a light (pointer) that produces a point of light that is reflected of the galvanometer mirror and is reflected on the translucent scale.

Accession Number:

Alternative Name:

Primary Materials: Wood, Metal, Glass


The front of the box has a company logo stamped on a metal plate. The top of the box has “JMP” carved into it, as well as a long blue label running diagonally across it, reading “Wheatstone Bridge Galvo–J.M. Perz”.

The back of the box has a metal plate with manufacturer’s information reading “Galvanometer”, “TYPE SRI-45”, “No. No. 1811”, “H. Tinsley & Co. Ltd.”, “St. Jerome P.Q.”.

Printed in white lettering on the top of the galvanometer mechanism: “No 118,076”

Dimensions (cm):

Length = 22 cm, Width = 16 cm, Height = 14.5 cm


For detecting and measuring electrical current.


The instrument is in good cosmetic condition and appears complete. The exterior of the instrument lightly marked and scratched, particularly on the top and base, and around the rim. There is a torn scrap of paper affixed to the top of the lid. The metal components of the galvanometer are in good condition; there is a brown residue on the hinge. All four rubber feet are present and in good condition.

Associated Instruments:


H. Tinsley & Co. Ltd., Saint-Jérôme, Québec

Date of Manufacture: c. 1930s-1950s


This artifact was part of a collection of electrical instruments (mostly brass electrometers and ballistic galvanometers) gathered by University of Toronto Professor of Physics Martin J.G. Lee (d. 2009). The collection was likely acquired from Dr. Lee’s office c. 2010 or 2011.

Markings on the instrument indicate that it was used by University of Toronto Professor of Physics John M. Perz. An email message received from Dr. Perz on March 17, 2023 notes that the galvanometer was likely used to select matched resistors in experimental apparatus.

Additional Information and References:

Historical Notes: Dr. Martin Lee’s Collection