Maker

Cooke, Troughton & Simms Ltd.

Model

S.500-109

Serial Number

SO41572

Dimensions

Telescope length 305mm, Height 160mm

Image

Description

This tilting level by Cooke, Troughton & Simms is a high precision levelling instrument primarily designed for first-order geodetic levelling.

The telescope is supported at its centre by a pivot and may be tilted (up and down) by turning the "tilting screw" which is located on the stage component of the level between the telescope and the base at the eyepiece end. This tilting screw enables the telescope to be precisely levelled before each staff reading, without altering the height of the telescope.

A parallel plate micrometer (range = ??) is attached to the telescope near the objective end (as seen in the image) for precise levelling. It is easily detached from the level when storing the instrument in the box. It's function is to determine the distance between the point where the line of collimation (line-of-sight) of the level intersects the staff and the next lower staff graduation, and thus eliminates the need for estimation.

One interesting characteristic of the instrument is that both the images of the tubular bubble and the observed staff are able to be viewed simultaneously through the eyepiece end of the telescope. The small lower eyepiece, located between the telescope and the tribrach next to the tilting screw, is for reading the horizontal circle, and is used for setting-out angles and for tacheometric surveys in reasonably level terrain.

History & comments

The tilting level is an exceedingly convenient instrument when only a very few sights have to be taken at each set-up, but it has the disadvantage that, when a number of sights have to be taken at one set-up, as in taking spot heights for contouring, it has to be levelled for every sight. 

Conservation

In a wooden box

Condition

Good

Remarks

• Catalogued by T. Ko
• Updated by F. Pall

Dates

Manufactured in 1940 (approx). Catalogued in 1997.