The experimental rod carries 2 metal plates at different points. These metal plates support a glass plate and a lens. One is on the top of other adjusted by 3 springs and screws. On applying a load the rods bend slightly, increasing the distance between the plate and the lens.Newton’s rings are observed before applying the load. As the load is applied gradually the rings run into the centre, disappearing one at a time. To the right is a microscope fitted with a micrometer eye piece scale for observing and making measurement upon the rings. The instrument is supplied w/o weights & Sodium Lamp Unit.