A Small Measuring Microscope

Abstract

A DESCRIPTION of a small measuring microscope devised by us may be of interest to readers of NATURE. The optical elements are extremely simple, consisting of a Ramsden eyepiece having a scale, divided on glass, which is permanently fixed in the focal plane. As the device is intended mainly for the observation and measurement of opaque objects, a thin parallel plate of glass is inserted at an angle of 45° between the lenses (Fig. 1). This serves to reflect diffused light on to the object observed and interferes very little with perception and measurement. In an eyepiece with a long working distance or using only an achromatic lens, the reflector may be interposed between the scale and the first lens. The instrument is, of course, equally available for the observation of transparent or aerial objects.