Unspecified / ca 1900
Hairspring Compass
Hairspring Compass
The Smithsonian catalogs Hairspring Compass as compass in its Mathematics records.
WHY IT’S INTERESTING
The handle on this metal instrument is connected to the point and can be pulled out of the cylinder that is the compass's main leg. The other leg is screwed to the cylinder with a metal slat. A screw goes through this leg and can be loosened or tightened to adjust the radius of a circle drawn with the compass. A second screw adjusts the tube that holds a pencil point. Draftsmen used the hairspring