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Low-Pressure Mercury Lamp

Physics

A black-painted wooden platform sits a metal support stand. Several electrical, including a transformer, a switch, and two long electrical leads, are attached to the platform. Clamped to the vertical stem of the stand is a glass element consisting of two cylindrical bulbs containing mercury. Electrical cords are attached to this glass element.

Accession Number: 2024.ph.881

Alternative Name:

Primary Materials: Wood, Iron Alloy, Mercury

Markings:

A red embossed label on the wooden platform reads: “LAMP 16”

Dimensions (cm): Height = 48, Width = 24, Length = 28.

Function:

This is a low-pressure mercury lamp, a form of gas discharge lamp, that was designed to provide a monochromatic source of light suitable for Raman spectroscopy. This is achieved by isolating the powerful 4358A peak in the spectrum of incandescent mercury using a filter typically consisting of a solution of sodium nitrite.

The lamp consists of two pools of mercury housed in separate electrodes. After the lamp is heated to produce gaseous mercury, a current is passed across the electrodes causing an arc to form through the mercury vapour.

This may be an early form of the “Toronto” mercury lamp. It does not have a water cooling jacket, which may or may not be an essential characteristic of a “Toronto”-type mercury lamp.

Condition:

This artifact appears to be intact. The metal stem of the stand is heavily rusted.

Associated Instruments:

Manufacturer:

Department of Physics, University of Toronto (Likely by glassblower Reuben H. Chappell)

Date of Manufacture: c. late 1940s.

Provenance:

Additional Information and References:

Historical Notes:

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