Accession No

2568

Brief Description

plug-type Wheatstone Bridge, Post Office pattern, by Gambrell Brothers Ltd., English, 1900-1950

Origin

England; London

Maker

Gambrell Brothers Ltd.

Class

electrical

Earliest Date

1900

Latest Date

1950

Inscription Date

Material

wood; hide (leather); plastic (ebonite); metal (brass); wax

Dimensions

length 259mm; breadth 210mm; height 179mm

Special Collection

Provenance

Transferred from Institute of Astronomy, University of Cambridge, Cambridge, England, 1980.

Inscription

“ACCURACY 1 IN 1000. CLASS B. No. 13182 Gambrell Bros. Ltd. London. GAMBRELL’S PATENT” (on top)

Description Notes

Plug type Whatstone Bridge, Post Office pattern, made by Gambrell Bros., 1900-1950; Rectangulare wooden box with hinged lid and leather handle; ebonite top; six brass terminals; two tapping keys with ebonite handles; twenty-three circular brass plug receptors (including one marked ‘INF’); twenty -three brass and ebonite plugs; three pairs of proportional coils of 10, 100, and 1 000 ohms, and sixteen coils from 1 ohm to 5 000 ohms, total 11 110 ohms; all twenty-two coils wound on wooden bobbins, wax coated, and fastened to underside of top plate

References

Events