Newton\u27s rings produced by a quartz plate and lens in a slit source of light were observed in a low power traveling microscope. The square of the radius of the rings ( r) plotted against the order of the ring ( n) from the center yields a straight line whose intercept on the axis where n = 0 is shown to be a function of the vertical separation of the lens and plate but not a function of the index of refraction of the medium between them nor the angle of incidence of the light. The ring radii were measured with air and with water between the lens and plate. The graphs for the two cases have different intercepts which is interpreted as indicating a rigid water multilayer between the quartz surfaces of the order of 200 AO in thickness
