Description:
The moving part of this instrument is encased within a sturdy brass frame. The moving part consists of a circular window in which is found a polarizer lens. This lens can be positioned sideways by sliding horizontally using the hand crank. A wingnut screw secures the moving plate in place. A scale divided in single millimeters shows the displacement. The lens can also rotate by a rack and pinion mechanism, the handle is missing. A scale 0-180°-0, divided in increments of five degrees, determines the rotation.