Protractors - Innovation While only one patent model for a
protractor survives in the Smithsonian collections—from an
inventor with a colorful personal history—several of the other
objects also provide examples of technical innovation. For
instance, some are manufactured versions of patented inventions.
Others were named for the person with whom they were associated,
even if that engineer or craftsman laid no claim to designing
that protractor. "Protractors - Innovation" showing 1 items. -
This brass semicircular protractor is divided by single degrees
and marked by tens from 10° to 90° to 10°. It is attached with
metal screws to a set of brass parallel rules. Brass S-shaped
hinges connect the rules to each other. The bottom left screw on
the parallel rules does not attach to the bottom piece. A
rectangular brass arm is screwed to the center of the
protractor. A thin brass piece screwed to the arm is marked with
a small arrow for pointing to the angle markings. The protractor
is stored in a wooden case, which