A good altazimuth compass-clinometer no. 622 by Casella c1900 in leather case

Altazimuth constructed in lacquered brass, the right side displaying a silvered azimuth circle (compass) marked with cardinal and intercardinal points, lines marking the false and by points, floating on jewelled suspension. The clinometer with eccentric weighted circular silvered and die struck dial carrying serial no. “622,” the circumference marked with quadrant scale 0°-90°-0°-90°-0° divided to 1°. Optical train consisting of eyepiece with push-pull focus for scales and sight line, the telescope with similar arrangement and including removable neutral density filter for brighter conditions. Separate japanned brass screw-in steadying handle or tripod mounting.

Presented in its original sturdy claret velvet lined leather case, buckle and strap fastening.

Condition: In much better than average condition, both compass and clinometer working correctly with all functions free and serviceable. The optical train clean and bright. The compass easily finds north and the clinometer responds accurately to angle change. Some minor ageing to compass and clinometer silvering. Externally maintaining much original lacquered finish, some minor marks.

The transport case sound, the stitching intact, the velvet lining bright. Marks and wear as expected from use.

Comments: A very good piece, particularly so as it all works and works well. This is an instrument that is relatively uncommon instrument, particularly with the original handle. One for the collector or an unusual gift.

Casella’s Pocket Altazimuth combines a sighting telescope with a magnetic compass for determining bearings, and a pendulum (or wheel) clinometer for determining vertical inclinations. Small, compact, and accurate, it was said to be especially useful for travellers and military surveys.

Louis Casella introduced the form in 1864, noting that is was “improved and modified by the kind assistance of Francis Galton, F.R.S.” The reference is to Francis Galton, (1822-1911), a Fellow of the Royal Society of London, whose work ranged over a number of fields. The image is taken from Casella’s catalogue of 1911.