Accession No

0204

Brief Description

“Y” level with tripod by Fairbone, c. 1800

Origin

New Street, Fetter Lane; London; England

Maker

Fairbone

Class

surveying

Earliest Date

1800

Latest Date

1800

Inscription Date

Material

metal (brass, silver, steel); wood; glass; string

Dimensions

height 1500mm; length of telescope 332mm

Special Collection

Robert Whipple collection?

Provenance

The association of this object with the Whipple collection is unclear.

Inscription

‘Fairbone,
New Street Fetter Lane
London’ (on telescope support)

Description Notes

Brass level, telescope with rack and pinion focus moving the objective; crosshairs and push-fit lens cover. Erecting telescope, bubble level slung below. Sliding shade for eyepiece. Mounted in “Y” mounts with clip and pin fastening (clips missing). Compass mounted centrally on telescope support, with silvered 8-point compass rose and two scales, one divided 0 - 90 - 0 - 90 - 0 numbered by 10, the other divided [0] - 360, anticlockwise, numbered by 10 subdivided to 1. Locking bar for compass needle. Elevation screw for levelling. Clamp on base for raising and lowering the instrument on the tripod. Wooden tripod with brass bound top and shod with brass. Legs divide in half and are held together with brass pins at the join.

Condition good; complete

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:39640