This instrument consists of a brass drum and disc (covered with paper numbered in pencil by ones from 1 to 25) mounted on metal stands that are fastened to a wooden base. U-shaped metal bars form a ...

This metal instrument (possibly of nickel-plated brass) has two pivoted arms with needle points. One is about 9" long, and the other is about 6-1/2" long. The longer arm is used for tracing and is ...