"Graphometer By Ian David Of Leiden, C. 1640-50"
Early Dutch graphometer signed "I. David". This is Ian David from Leiden. The instrument therefore dates back to the years 1640-1650. The instrument is engraved with two scales of 180° degrees, then divided into four times 90° degrees. Very nicely engraved, the instrument presents some decorative elements under its suspension ring, along its pinnules and around the compass. The original needle no longer moves perfectly but is still magnetized. Dutch surveying instruments from this period are unusual. Missing his kneecap and his foot. 24cm in diameter and 14.5cm in height (without the ring). 
Le Magazine de PROANTIC
TRÉSORS Magazine
Rivista Artiquariato