General Information

Serial #

N/A

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

metal casing, stand, scale holder, wiring, parts/ glass window/ cardboard scale

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

20.0 cm

Width

13.8 cm

Height

25.3 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Physics

Category

Demonstration & teaching equipment

Sub-Category

N/A

Manufacturer

AKA

Welch

Country

United States of America

State/Province

Illinois

City

Chicago

Context

Country

Canada

State/Province

Ontario

Period

early 20th century

Canada

This piece of equipment was used at the Chatham Collegiate Institute in Chatham, Ontario, a secondary school which was founded in 1885 and closed in 2003. In 1851 the first school was established in the village of Chatham and by the late 1870's it was called Chatham High School. In 1885 the school attained the status of a collegiate institute, enabling it to obtain larger provincial grants and by 1887 a new school building had been constructed and the CCI was considered to be one of the most outstanding secondary schools in Ontario (it was destroyed by fire in 1946). In 1940 a new building was completed & again was considered to be one of the most modern educational facilities in the province. The school was closed in 2003.

Function

An instrument for detecting the existence & determining the strength of small electric currents, in this case to demonstrate principles of electricity in a school.

Technical

A small, self contained D'Arsonval galvanometer designed for general laboratory use, available in the 1927, 1928 & 1949 Welch catalogues. The instrument consists of an upright, glass-fronted metal box. On either side are the poles of the permanent magnet used to set up the constant magnetic field used to provide the torque on the current-carrying coil. The coil is suspended from the top of the box by a thin phosphor-bronze strip, with the lower suspension being a loose coil of the same material. The reverse side of the curved strip mounted at the end of the long foot carries a scale with reverse-printed numbers. The user looks through the rectangular aperture mounted above the curved strip, and sees the scale in the small mirror attached to the coil. To keep the eye fixed in the same position, the image of the centre line reflected from a small mirror on the surface of the glass cover is always kept in coincidence with the centre line observed in the rotating mirror (Ref. 3).

Area Notes

Unknown

Details

Markings

black lettering on scale reads "W.M. WELCH SCIENTIFIC COMPANY/ CHICAGO, ILLINOIS"/ black & red scale markings

Missing

appears complete

Finish

black wrinkle finish on casing/ colourless transparent glass/ glossy black painted base/ flat black painted parts/ metallic & copper coloured parts/ white scale

Decoration

N/A