Lens Holder

For parallelogram and polygon of forces. A strong drawing board 750 x 600 mm, fitted with brackets for fixing to a wall. Clear space is left all round the edges for attachment of pulleys etc., supplied with pulleys, cords but without masses.

The Equal Mass Metal Cylinder Set includes Aluminum, Copper, Brass, Tin and Zinc. Each Cylinder measures ½” in diameter and has the same mass, 20 gm.