Details
A rare, late 17th-Century brass protractor and scale rule instrument,
signed on the underside of the protractor Christian Boÿÿling Mechanicus Dresten 1670, the upper face of the protractor engraved along the base line with floral decoration and pierced with foliage, the protractor engraved with two scales, a full 0°- 180° scale to the outer edge, the inner divided into two quadrants, the compass with brass-capped, iron needle, the compass box secured to the underside of the protractor by three screws, the back side fitted with ring and pin-hole sights secured by two screws and dowel pins, the rule engraved with two scales, fitted to one edge with a vernier scale with fifteen divisions reading against the outer protractor scale, attached to the scale rule are two eared screw nuts -- the rule 10in. (25.4cm.)
long
See Colour Illustration and Detail
signed on the underside of the protractor Christian Boÿÿling Mechanicus Dresten 1670, the upper face of the protractor engraved along the base line with floral decoration and pierced with foliage, the protractor engraved with two scales, a full 0°- 180° scale to the outer edge, the inner divided into two quadrants, the compass with brass-capped, iron needle, the compass box secured to the underside of the protractor by three screws, the back side fitted with ring and pin-hole sights secured by two screws and dowel pins, the rule engraved with two scales, fitted to one edge with a vernier scale with fifteen divisions reading against the outer protractor scale, attached to the scale rule are two eared screw nuts -- the rule 10in. (25.4cm.)
long
See Colour Illustration and Detail