Accession No
2448
Brief Description
dumpy level, by E. R. Watts and Son, English, 1922
Origin
England; London
Maker
E. R. Watts and Son
Class
surveying
Earliest Date
1922
Latest Date
1922
Inscription Date
1-3-1922
Material
metal (brass, nickel silver, 1 other); glass; wood
Dimensions
box length 395mm; breadth 185mm; height 166mm
Special Collection
Provenance
Transferred from Department of Engineering, University of Cambridge, Cambridge, England, 09/1979.
Inscription
‘ERW & S’ (logo, in triangle)
‘E.R. WATTS & SON LONDON No 8519’ (on level)
‘Patent No. 114036 - 1917 Regd. Design No. 665992 L2’ (on level)
‘AGENTS J.Halden & CO. Ltd
Manchester and London’ (on level)
‘Instrument No. 8519 Date 1.3.22 Constant 1:56 Stadia 1:1000 Lab No. LA’ (label in box)
’ (label in box)
Description Notes
Metal alloy body with khaki finish. Brass eyepiece. Nickel silver screws. Axis clamp. Azimuth motion tangent screw. Rack and pinion focus and secondary eye focus. Bubble mounted on left side of telescope, hinged mirror over and white plastic reflector below. Bubble graduated in 1/10´´. Transverse bubble below eyepiece. Inverting telescope with cross-hairs and ray-shade. 3 foot screws in tribrach limbs. Spare eyepiece. Fitted wooden box.
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:42873
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