Westinghouse Arc Lamp Gauge and Viewer

Westinghouse Arc Lamp Gauge and Viewer

Current location:

Collection Storage Facility


Ontario Hydro acquired this artifact for its Museum of Electrical Progress in the late 1960s, transferring it to the national collection in 1992.

Technical history:

These are early examples of tools used by an arc lamp repairman, called a trimmer, to maintain and service street lamps. The gauge permitted the trimmer to measure the maximum and minimum diameter of carbons installed to produce an electric arc in a lamp. The mica viewer allowed the trimmer to observe the colour of the light and to diagnose potential problems.


The first arc lamp in Canada was installed in the Davis House hotel in Winnipeg on March 12, 1873. Five years later, J. A. Craig demonstrated the Yablochkov candle and arc technology in Montreal. Although the first arc lamps were open — they did not have globes — by the 1890s almost all commercial arc lighting used safer and more stable enclosed lamps. These lamps required extensive cleaning and regular maintenance. As the incandescent technology became available, the use of arc lamps declined by the 1920s.

Canada Science and Technology Museum
Artifact No.
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United States
Manufacture Date
Acquisition Date