Accession No
0670
Brief Description
compass, surveying, by G. Gerlach, 1850 (c)
Origin
Poland; Warsaw
Maker
Gerlach, G.
Class
surveying
Earliest Date
1850
Latest Date
1850
Inscription Date
Material
metal (brass, silver, alloy)
Dimensions
length 439mm; breadth 161mm; height 72mm
Special Collection
Robert Whipple collection
Provenance
Purchased from N. Feigenbaum on 07/04/1931. S - to Kryska, Nr. 30, Warsaw
Inscription
‘G Gerlach Varsovie No 1040’ (on compass face)
Description Notes
Brass; fixed linear member. Centrally mounted compass. Silvered rose graduated 0-360˚ and 0-90-0˚ twice to 15’. Engraved N.O.S.W. Locking bar operated by milled screw. Metal alloy sights; window and 7 pinholes. Hinged, and screwed onto linear member. Clamp and socket below for attachment to tripod.
References
Events
Description
The circumferentor is an instrument that derives from the reverse side of an astrolabe. It is used to measure horizontal angles, or vertical angles by suspending the instrument from its shackle.
The circumferentor was described by Arthur Hopton in 1611, though passing references had been made to it in earlier works. It became one of the standard pieces of equipment of the surveyor throughout the 17th and 18th centuries.
31/08/2006
Created by: updated by Ruth Horry on 31/08/2006
FM:43353
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