Accession No
3401
Brief Description
sounder, “Walker’s Harpoon II Depth Finder”, by Thomas Walker and Son Ltd., English, 1850 - 1900 (c)
Origin
England; Birmingham; 58 Oxford Street
Maker
Thomas Walker and Son Ltd.
Class
navigation
Earliest Date
1850
Latest Date
1900
Inscription Date
Material
metal (brass, lead)
Dimensions
box height 206mm; breadth 152mm; depth 73mm
Special Collection
Provenance
Purchased from Historical Technology Inc., Massachusetts, USA, 1986.
Inscription
‘Thos. Walker & Son, Ltd.
58, Oxford St, Birmingham’ (red plate on underside of centre of fly)
Description Notes
Sounder, “Walker’s Harpoon II Depth Finder”, by T. Walker & Son, English, c. 1800 - 1900.
Mechanical sounder / depth finder where the fly, connected to the counter, rotates as the sounder descends. Counter is brass with a dial for 0-30 fathoms, enclosed in a red painted circular case. Long hexagonal black painted lead sounder. Fly is engraved with T.W.’s triangular seal.
Condition: good; complete.
References
Joshua Nall; ‘Navigational Arts’; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge; 2020: https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/astronomy-and-empire/navigational-arts
Events
Description
Attached to the ship’s rail by a line, the sounding device is cast overboard and carried down by its lead weight. As it descends, the vane turns a toothed wheel which in turn drives a counter. When the lead strikes the sea bed, the sounder is hauled up. The toothed wheel is locked on the way up, and the reading is a measure of the distance between surface and sea bed.
04/08/2008
Created by: Dr Anita McConnell on 04/08/2008
FM:44387
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