Maker

Troughton & Simms, England

Model

N/A

Serial Number

N/A

Dimensions

Telescope Length 250 mm, Height 400 mm

Image

Description

This is a four-foot-screw Vernier theodolite with a brass pillar frame, incorporating a vernier reading system for the horizontal and vertical circles. The circles are equipped with magnifying glasses attached at opposite ends of each circle for more comfortable vernier reading. 

The instrument consists of: (1) a levelling head which supports the main working parts of the instrument and is capable of being screwed onto a tripod, (2) a lower circular horizontal metal plate with a silver vernier graduation, (3) an upper circular horizontal plate, (4) a vertical circle with vernier graduations and (5) a telescope with the altitude bubble attached beside the vertical circle. 

There are however two extra components as additions to the typical vernier theodolite components. These include a 'striding level' and a 'trough compass'. The striding level is mounted on top of  the trunnion axis of the theodolite by two legs with V-shaped ends, and is perpendicular to the telescope. It is used for accurately determining the tilt of the horizontal axis, and can be easily detached from the theodolite enabling the telescope to rotate freely. The trough compass on the other hand is located in the centre of the alidade and is used to determine the direction of magnetic north. 

History & comments

There is no historical information available.

Conservation

In a fine wooden box

Condition

There are slight scratches on the vertical circle

Remarks

• The instrument can be separated into several components and conveniently stored in a small wooden storage box (shown on the left image).
• Catalogued by T. Ko
• Updated by F. Pall

Dates

Manufactured in 1900 (approx). Catalogued in 1997.