Accession No

0910

Brief Description

bimetallic thermometer, 1875 - 1925

Origin

Maker

Class

meteorology; thermometry

Earliest Date

1875

Latest Date

1925

Inscription Date

Material

metal (brass, steel, white metal); glass; paper

Dimensions

length 147mm; breadth 119mm; depth 48mm

Special Collection

Robert Whipple collection

Provenance

Inscription

‘FREEZING
FAHRENHEIT
PATENT
METALLIC THERMOMETER’ (on dial)

Description Notes

BIMETALLIC THERMOMETER, 1875 - 1925. Round brass casing with suspension loop and patterned opening on far side from suspension point to allow air access to the bi-metallic strip. Glass front reveals varnished paper dial and steel index. Scale divided [-]30 to [210] numbered by 10 subdivided to 2.

Complete

References

Events

Description
The element of a bimetallic thermometer consists of a strip or coil of steel bonded to another metal, usually brass. The element is able to measure temperature because the two metals differ in their expansion when heated, causing the element to coil up more tightly when heated, as one metal pulls against the other. One end of the coil is fixed, the other is linked to the pointer, which moves round a dial graduated in degrees Fahrenheit.

The Fahrenheit scale takes 32 as the freezing point and 212 as the boiling point of water. It is named for the instrument maker Daniel Gabriel Fahrenheit (1686-1736) who spent many years perfecting thermometers.
26/03/2008
Created by: Dr. Anita McConnell on 26/03/2008

FM:42190