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Relative Humidity Indicator


This is a disk-shaped instrument with a glass top cover set in a silver-coloured metal rim. Under the glass cover is a face with a semi-circular scale graduated in units from 0 to 100 curving around the top rim. These are labelled in tens, and not evenly sized. A needle pointer is fixed at the centre of the face. On the face of the dial are the words “Airguide” and “Percent Relative Humidity”. The face and glass cover is mounted on a black plastic base with a hole in the back to facilitate hanging.

Accession Number:

Alternative Name:

Primary Materials: Glass, Metal, Plastic


On the face: “Airguide” “PERCENT RELATIVE HUMIDITY”

“Made in U.S.A By Airguide Instruments Company Chicago”

Dimensions (cm): Height = 4, Diameter = 13.5


This instrument measures relative humidity.


Excellent: The instrument is in very good condition, with little sign of damage or use.

Associated Instruments:

Manufacturer: Airguide Instruments Company, Chicago

Date of Manufacture: 1930s-1980s Century


Department of Physics, University of Toronto

Additional Information and References:

Historical Notes: