Accession No
0920
Brief Description
Y level, by Edward Troughton, circa 1800
Origin
London
Maker
Troughton. Edward
Class
surveying
Earliest Date
1800
Latest Date
1800
Inscription Date
Material
metal (brass); glass
Dimensions
length 513mm; breadth 123mm; height 174mm
Special Collection
Robert Whipple collection
Provenance
Inscription
on the compass face
Troughton London
Description Notes
Y Level made by Troughton circa 1800. Brass telescope. with erecting lens. Rack and pinnion focussing movement moving objective. Bubble mounted over telescope. No graduations. Lens cover. Y supports. Compass mounted centrally. Graduated in 10 degrees on compass face, with single degree scale above. Elevation screw extends from Y support. Pillar base fits onto tripod head (no foot screws).
References
Events
Description
The earliest form of modern surveyor’s level is the ‘Y’ level, which is a telescope supported in Y-shaped bearings. The telescope is held in place by pivoting straps, which allow the telescope to be reversed for back-sighting.
The Y level was unsuitable for difficult colonial terrain, requiring too frequent adjustments and the ‘dumpy’ level was developed in the early 19th century to overcome this. The dumpy level has a much shorter, fixed telescope, which turns about a central axis. It is compact, much more robust and is still being used in largely unaltered form on building sites and in road construction.
31/08/2006
Created by: updated by Ruth Horry on 31/08/2006
FM:42900
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