Accession No

3258

Brief Description

Ewing’s (?) extensometer, early 20th C.

Origin

Maker

Class

metrology

Earliest Date

1900

Latest Date

1950

Inscription Date

Material

metal (brass, at least 3 white metals); glass; wood

Dimensions

length 268mm; depth 210mm; height 147mm; box length 400mm; breadth 332mm; height 182mm

Special Collection

Provenance

Transferred from Department of Engineering, University of Cambridge, Cambridge, England, 08/1985.

Inscription

‘EWING’S PATENT’ (on right bracket)

Description Notes

Two brass brackets are interconnected by means of a white metal strip. Each bracket carries a pair of pointed screws with knurled brass heads, to secure sample. Two other white metal rods join the 2 brackets. The larger rod is fixed to the right hand bracket and is held onto the end of a screw on the left hand bracket by a spring. A knob on the left hand bracket can be rotated, to move to screw in and out, hence moving the brackets further apart or closer together. This knob has scale divided 0 - [20] numbered by 5 subdivided to 1. The second white metal rod is also connected to left hand bracket by a sprin, but rests, and moves within, a standard on the right hand bracket. An aperture in this rod carries a vertical hair-line. The right hand bracket terminates in a cylindrical mount for a telescope, to read the hair-line, with the aid of a swivelling mirror at the rear (telescope missing). Fitted wooden box, with brass hinges, lock (no key), carrying handle and hook fasteners. Two pointed screws with knurled heads in box.

Condition fair (lid of box split); incomplete

References

Events