Accession No

6667

Brief Description

level and angle indicator, by Fletcher and Sinclair, English, late 19th Century

Origin

England; Liverpool; 62 Duke Street

Maker

Fletcher and Sinclair

Class

surveying

Earliest Date

1860

Latest Date

1890

Inscription Date

Material

wood; glass; metal (brass); paper

Dimensions

102/205mm (width, closed/open) x 258mm (length) x 35mm (height)

Special Collection

Michael J. Clark Bequest

Provenance

Inscription

Description Notes

Level & Angle Indicator, by Fletcher & Sinclair, English, late 19th c.

Three dials are set into a wooden case with brass hinged lid. The uppermost is a sundial, with folding paper gnomon that has "London" written on it (it would need to be changed to give an accurate reading outside of London). The middle instrument is the eponymous level and angle indicator: a weighted metal needle sunk into the wooden case with a glass cover and brass ring almost flush with the wooden case. The face of the level and angle indicator bears the name of the instrument maker, as well as a repeating 0-45-90-45-0 degree scale around the exterior, allowing the user to obtain an angle measurement. The third instrument is a compass, with intercardinal points and a degree scale.

A hole has been bored through the wooden case along the side opposite the hinge. By looking through this sighthole at a distant object, the user can take a measurement of the angle between the ground and her line of sight leading to the object; if she knows the distance between herself and the object, she can then calculate the object's height.

Typed instructions from the makers are pasted inside the hinged lid. The instructions describe the functions of the instrument show how to calculate height based on angle and distance, using a set table or by calculating oneself.

Condition: good, complete

References

Events