I. Sneewins brass sector, C 1650.
An early dutch brass Sector by Johannes Sneeuwins (1610-1675), C 1650. The instrument is signed with “I. (Johannes) Sneewins FE”. he worked as a clockmaker in Utrecht and madeinstruments for the observatorium in Utrecht.
A sector or proportionaalpasserÂ is a mathematical instrument, which in terms of construction somewhat resembles a regular passer but in function more close to a slide rule. Proportionaalpassers were out in force starting from 1597 built by Galileo Galilei, to whom the invention is often wrongly attributed. These mechanical instruments were used before the invention of the calculator. Full length 52 cm