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A grey metal case containing a clock-driven rotating drum in an enclosed chamber. In an adjacent section there is a bi-metal strip for measuring temperature and a (horse?) hair bundle for measuring humidity. Each substance actuates a separate recording arm that records temperature and humidity data, respectively, onto a chart clipped to the rotating drum. The drum can be set to rotate either daily or weekly. This device has a temperature chart attached to the drum. The pen is missing from the humidity recording arm.

Accession Number:

Alternative Name:

Primary Materials: Metal, Glass, Paper, (horse?) hair.


A sticker on the side of the instrument reads “HYGRO-THERMOGRAPH; RECORDING RELATIVE HUMIDITY; AIR TEMPERATURE; MODEL 594; SERIAL NO 12583; THE BENDIX CORPORATION; FRIEZ INSTRUMENT DIVISION; BALTIMORE MARYLAND”. “PLT PATH” is written at the bottom of this sticker in pencil. A sticker below this reads “PROPERTY OF UNIVERSITY OF TORONTO”.

“Ser No. 12583; Model 594; 696930” is written on a sticker fixed to the underside of the cylinder. “Plt Path” is scratched into the top and front of the instrument.

The bottom of the recording drum (?) is stamped “FRIEZ INSTRUMENT DIVISION; BENDIX AVIATION CORPORATION; BALTIMORE MD USA.” A sticker attached to the bottom reads “696930”.

Dimensions (cm):

Height = 21.5, Width = 14.3, Length = 30.6


Measurement of temperature and humidity.


Very good condition. The rotating drum is functional.

Associated Instruments:


Friez Instrument Division, Bendix Aviation Corporation, Baltimore, Maryland, USA.

Date of Manufacture: c. 1960-1980


Acquired from Botany in 2004 with the assistance of Keioko Yoshioka. Last recorded date on drum is Feb. 1967.

Additional Information and References:

Historical Notes: