Accession No
2454
Brief Description
dumpy level with tripod, by Troughton and Simms, c. 1880
Origin
London; England
Maker
Troughton & Simms
Class
surveying
Earliest Date
1880
Latest Date
1880
Inscription Date
Material
metal (brass, 1 other); glass; wood
Dimensions
level box length 482mm; breadth 125mm; height 104mm; tripod height 1425mm; maximum diameter 78mm
Special Collection
Provenance
Transferred from Department of Engineering, University of Cambridge, Cambridge, England, 09/1979.
Inscription
‘TROUGHTON & SIMMS
LONDON’ (on level)
‘John Davis & Son Derby’ (box)
‘overhauled 27/3/12’ (label in box)
plus other trade label(s)
Description Notes
Metal alloy construction with brass screws and eyepiece. Telescope with rack and pinion focusing. Inverting lens. Cross hairs (2 vertical); ray shade. Bubble mounted over telescope graduated in 1/10´´. Transverse bubble over the objective lens. Compass mounted below telescope. Scale graduated in single degrees. Locking screw. 4 foot screws through parallel plates. Milled ring controls azimuth motion (no clamp). Spare eyepiece. Magnifying glass for reading compass scale. Fitted wooden box. Tripod
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:42878
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