Small Canivet Graphometer Dated 1764

Brass graphometer with solid plate, not perforated, a beautiful thickness of 4mm, signed "Canivet à la sphere à Paris" and dated "1764". We do not know of any other graphometer from this period with a non-perforated plate/plate. The instrument measures 15.5 cm in width. It is complete with its kneecap and its foot, its four pinnules, two of which are mounted on a mobile alidade, its original compass and needle. Old cleaning but extremely rare model of a Canivet graphometer. In addition, the instrument has kept its original shaped box (the two slots for the pinnules are however missing).