This is a side arm for a microscope made by Leitz. I presume it is for a second person to view or to be used as a drawing aid like a camera Lucida. There is a prism above the main optical axis of the microscope which reflects some of the light to the side. There is an eyepiece lens which can be moved closer or further from the prism as required. There is then a possibly face silvered mirror at 45 degrees to view the image. I presume that if a piece of paper is put on the other side the effect would be that of a Camera Lucida to enable drawing of the slide. It is in the original box which was foam lined but it turned to mush and stuck to everything which took quite of lot of cleaning to remove. This will be sent insured and signed for.
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