Newton Ring Apparatus wooden frame

Comprising a small wooden frame of size 5”x3”x3” with a matt blackened inside and provided with a glass plate 4” x 3” x 1/8 mm mounted at an angle of 45 degree to reflect the light downwards on to a Plano-convex lens of 50mm diameter having 100 cm focal length which rests on a plain glass plate3” x3” x3/8 on the base of the box.