摘要 |
An eyepiece for use on a microscope when lengths and angles are to be measured. Two glass plates extending perpendicular to the optical axis of the eyepiece are spaced axially from each other to form between them a chamber containing a steel ball which is free to move, by gravity, to the lowest part of this chamber and which thus forms an artificial horizon. One of the glass plates, preferably the one farthest from the eye of the observer, is formed as a reticle, graduated with a diametrically extending linear scale and also with a circumferential series of radially extending angular graduations, read in conjunction with the steel ball to make the desired angular measurements.
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