Unspecified / early 20th century
Hairspring Compass with Lengthening Bar and Pen Point
Hairspring Compass with Lengthening Bar and Pen Point
The Smithsonian catalogs Hairspring Compass with Lengthening Bar and Pen Point as compass in its Mathematics records.
WHY IT’S INTERESTING
This metal compass has a cylindrical scrolled handle. The upper parts of the legs have decorative grooves on either side. A thumbscrew on one leg may be used to finely adjust the angle of the leg (hence, the name "hairspring"). The lower parts of the legs are hinged and are attached by screws so that the pencil point and needle point may be replaced by the pen point or lengthening bar contained wi