ABBE-TYPE CAMERA LUCIDA

Shown here is a Abbe-type camera lucida, as made by the American firm of Bausch & Lomb. It is clamped around a microscope eyepiece. In use, the user looks through a prism in the round eyepiece covering and sees both the object in the microscope, and superimposed, the reflected image of the drawing surface. By rotating the ring around the prism, different densities of filtration are provided to equalize the brightness of the drawing surface to the image in the microscope. The mirror can be moved closer or futher from the microscope and its angle is easily adjusted. It can be used with microscope in an upright position. It can also be used with the microscope inclined. With the microscope in the vertical position, the mirror angle is 45 degrees. When the microscope is inclined, an angle other than 45 degrees will be needed and an accessory tilting drawing table must be used to avoid distortion of the drawing surface. The prism housing can be rotated in and out of the optical axis without the need to unclamp the device from the microscope eyepiece. This type of camera lucida was quite popular and supplied by many different makers. It is signed 'BAUSCH & LOMB, OPTICAL CO., ROCHESTER NY U.S.A.'