Rototherm Brown Bakelite Dual Scale Desk Thermometer

A mid-20th century desktop thermometer in brown, with readings in Centigrade and Fahrenheit. Second-hand.
Availability: Out of stock.
Stock ID: 993

What's for sale?

This is a mid-20th century desktop thermometer cast in brown Bakelite.

It's a bimetallic thermometer made by the British scientific instrument manufacturer Rototherm. It is a rarer model with readings in Centigrade and Fahrenheit.

It has a white dial and a black needle providing measurements in degrees Celsius on the red scale, and in degrees Fahrenheit on the black.

It can be calibrated by removing the rear panel and gently twisting the back of the needle assembly. We have checked it using a digital thermometer and it seems to keep within about 0.5°C.

Bakelite has become a generic description for items made of early plastics and resins, like Lucite, Catalin, Galalith, Bakelite and urea-formaldehyde resin. The Rototherm thermometers were apparently made from urea-formaldehyde.

Who made it and when?

It was made in England by Rototherm. They invented the bi-metallic thermometer and the patent number GB378314 on the dial was published on 11 August 1932. This example was probably made in the 1930s or 1940s.

What condition is it in?

  • Second-hand
  • In very good condition
  • No cracks or chips
  • The red text may have faded over time
  • The black access panel has lost some paint
  • The readings are quite accurate

What are the measurements?

  • 9cm high (3.5 inches)
  • 10cm width at the base (4 inches)
  • 7.5cm depth at the base (3 inches)
  • 167 grams

If you have any questions, just send an email to

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