Leveling Alidade Of Colonel Goulier

Signed "BELLIENI À METZ", 1850-1870, Brass and steel on boxwood.
Boxwood ruler, 15 cm with divisions in millimeters, this one is equipped on one side with a three-eye brass sight pinnule, and on the other, with an alidade (vertical sight from 0 to 40) with a vertical hairline allowing to transfer onto a drawing sheet the horizontal projection of a chosen direction. In the middle of the base is a glass and brass spirit level screwed onto the base, it is surrounded by 2 eccentric levers allowing to rectify the horizontality of the device. The ruler has a logarithmic slope scale ranging from 1.5 to 100. The instructions for using the alidade are printed and glued to the back of the base.
This instrument was designed by Colonel Charles-Moÿse Goulier (1818-1891), professor of geodesy and topography at the École d'application de l'artillerie et du génie, in Metz, who perfected a number of measuring instruments and left his name to many inventions in this field, particularly the topography of mountainous regions. (See Daniel David, "Le colonel Goulier et la topographie des fortifications", Revue historique des armées, 268 | 2012, 99-109.)
The maker was Henri Bellieni (1857-1938), a French optical engineer and photographer. After the Crimean War, he became the official supplier of precision instruments to the French Army, including goniometers, leveling compasses, alidades, spotting scopes, and binoculars of all kinds. The Bellieni family left Metz and settled in Nancy in 1871.
The instrument is in perfect condition.