Large Surveying Circle By Vionnet, 18th Century

Large surveying circle with four folding pinnules, two of which are mounted on a rotating circle. This large circle is 29.5 cm in diameter and whose pinnules measure 8.5 cm in height and bears the enigmatic signature of "G. Vionnet in Paris". The instrument is complete with its pinnules, its ball joint and its foot. The instrument is stored in a wooden box lined with circular velvet and where, at the time, other mathematical instruments such as proportion compasses, protractors, ruler and level were also kept. The circle is doubly engraved with 0-360 and 360-0 degrees. It is of simple but elegant construction decorated with a few volutes. Good condition for this certainly unique instrument and very large for a surveying circle, called a Dutch circle. Vionnet is not known to any bibliographer. The instrument can be dated to the middle of the 18th century. The round box measures 30.5 cm in diameter.