The apparatus consist of a circular wooden top 300mm diameter and 12mm thick attached to a strong ballbearing spindle provided with a driving pulley, 80mm diameter and a support rod for mounting in a large tripop base or boss head.

For verifying the laws of composition and resolution of forces, comprising a metal table 30cm dia. Its edges divided scale graduated 360°, on heavy vertical support rod and tripod base.

Searle's pattern. The instrument consisting of two frames connected by a link. The frames are fitted with self centering chucks. An accurately graduated micrometer screw to read to 0.01mm is fitted on one frame.