The ammeter is set in a square, wooden, varnished stand, with a simple flat base and a vertical wood panel with the ammeter’s case set through it. A pair of triangular braces support the vertical piece on either side, sloping backwards.
The ammeter itself is cylindrical with a round face. A arc-shaped scale is in the top section of the face; the scale, set behind glass, runs from 0-20, calibrated in millamperes and labelled from 10-0-10, with zero at the centre. There is an indicator needle at rest pointed at zero. Beneath the scale on the black face of the ammeter, there is a maker’s mark and information about the instrument.
Two large posts emerge from the rear of the ammeter case. These are connected by plastic-insulated wires to a pair of electrical terminals affixed to the base. The two terminals are labelled with “+” and “-” symbols. The wire that runs to the positive terminal runs through a fuse before reaching the ammeter.
Accession Number: 2009.ph.166
Primary Materials: Wood, Metal, Glass
Old inventory number = phy1024. This is handwritten on a pale yellow note that is stuck to one of the triangular supports of the stand.
The face of the ammeter has raised lettering which reads: “Wagner Electric Mfg. Co.”, “Type R”, “St. Louis, U.S.A.”.
Handwritten in black ink on the rear of the wooden stand, above the ammeter case: “10-0-10 MILLAMPERES”
Height = 33 cm, Width = 30 cm, Length = 29 cm
Measuring amperage in an electrical circuit; possibly a demonstration device.
Very Good: The wooden stand is in good condition, although in places, particularly on edges and corners, the varnish is chipped. There are a few small scratches on the surface of the wood. The bronze-coloured metal surface of the front of the ammeter is somewhat oxidized (dulled). The scale and case is otherwise in excellent condition.
Wagner Electric Manufacturing Company, St. Louis, Missouri, USA
Date of Manufacture: 1891-1967 (likely before 1930)
Department of Physics, University of Toronto
Additional Information and References: