A quite unusual simplified late form of a squadra mobile without shadow square. The instrument is built in brass. It is certainly French, circa 1700.
At the center of the joint is a small and simple sight. At the other side of the two lines engraved on the two arms two other simple sights which can be slided for a right use.
The semi-circular scale is engraved from 0 to 180 degrees and in the inner side 0 to 60, 60 to 0, 0 to 60 and 60 to 0 degrees.
At the back side, a balljoint of archaic form (a little bent).
In addition, the instrument can be used like a large protractor with arm or like a simplified graphometer if we unscrew the two decorative screw at the back.
A simplified surveying’s compendium based on the original squadra mobile.
34 cm width.
Ask the Dealer
Established by Alexandre Piffault in 2014 and based in Paris at 5 rue de Condé, 75006, very close to Odéon, Le Zograscope specializes in antique and rare books in Science, Medicine and Technology, and rare antique instruments in the same fields. We have especially a strong interest in early and continental microscopy, early and special mathematical/drawing instruments, medical and surgical instrument, and rare technology.