General Peigné's Alidade Compass

Signed "Paris, Delagrave & Cie, Editeurs - Système du Général PEIGNÉ", [c. 1905-1910], Mahogany and fruitwood case, blued steel needle, black metal alidade, brass hooks and brake, sighting mirror.
A compass that can be used as a planimeter, for levelling and slopes.
Equipped with a 320-division, 20-millimeter limb and a 16-cm graduated ruler on one side of the compass.
Instrument used by the army, which calculates the maximum degree of slopes that can be traversed by motorized vehicles, horses and infantry.
The inventor was Paul Peigné (1841-1919), a polytechnician and artillery officer, Major General and French Freemason (Grand Master of the Grande Loge de France from 1910 to 1918), implicated in 1904 in the "fiches affair" he was reinstated in 1905 and given the presidency of the Artillery Technical Committee.
With indications printed on paper on the lids of the "Angles of slopes in thousandths" and of the operation of the alidade compass.
Instrument in working order, note the slightly pitted complexion of the sighting mirror and on one side of the compass crack and small lack on the edge of the ruler but which does not prevent its functionality.
Dimensions: 9 x 9 cm - Thickness: 3.5 cm - diameter: 7 cm