Maker

J. Y. C. Richmond

Model

Designed by J. Y. C. Richmond

Serial Number

N/A

Dimensions

Diameter 90 mm, 14mm high

Image

Description

Circular slide rule type device for the calculation of horizontal distance and height difference from 'stadia' readings on a vertical (levelling) staff. The inner disk is rotated unil the arrow points to the staff intercept read. Then, the readout line can be rotated to the read elevation (or slope) angle. Read the horizontal distance on the outer scale, left of arrow. The elevation angle for the height difference readout is spread over four concentric scales (1 - 4', 4' - 40', 0°40' - 6°, 6° - 40°). Disks in acrylic glass.

The text on the dial reads as follows:

'Set arrow on staff interval. The horizontal distance may then be read from the scale to the left & the difference of level from the other scale. Both results are read off the outer scale. The percentages are a guide to the position of the decimal point in levels.' - 'Designed by J.Y.C. Richmond F.I.S. N.S.W. 1942'

History & comments

Designed in 1942.

Conservation

no case

Condition

Main plate hard to turn. Inner disk slightly warped.

Donated by Mr. Bill Dive in June 1999.

Photo by JMR.

Dates

Catalogued by JMR on 21.8.2000.