Binocular Polarizing Microscope

Production date
Circa 1918
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Object Detail

Watson and Sons Patent 64 polarizing microscope. Coarse focus is by rack and pinion. Fine focus is by adjustable micrometer knob. Plano-concave mirror. Finished in lacquered brass.Three feet mounted on timber base, with timber clamps over each foot, screwed down. Column-style brass legs. The microscope comes with two sub-stage condensers – one with optical Abbe type condenser, variable diaphragm, and removable filter holder, the other with rotating wheel stops. Incorporates a prism.
CH classification SCIENCES Instruments Optical microscope
Production place
L240 x W310 x H540 mm
Media/Materials description
Indeterminate (Woods)
Brass (Metals - Non-Ferrous)
Indeterminate (Glass)
<on leg> WATSON & S [covered] \ 313 High Holb [covered] \ London \ 1918
<on round plate > WATSON & SONS. \ PATENT \ 64
<on left eye piece > C \ KELNER
<on right eye piece> C \ KELNER
History and use
This microscope is a polarizing, or petrological, microscope, used for identifying rocks and minerals in thin sections with the use of polarised light. The microscope, made by English manufacturer Watson and Sons, has a lateral illumination mirror attached to aim and focus more light at the object of study.

Binocular microscopes only differ from monocular microscopes because they have two eyepieces rather than one. They are still compound microscopes (producing a two dimensional image) but they allow for the use of both eyes. Using two eyes is physically easier and it has been claimed that using both eyes provides better depth perception. However, the use of a prism in this Watson and Sons model gives the image a definitively more three dimensional look. The prism splits the light by combining reflection and refraction to give a pseudo-stereoscopic effect.

Uploaded to the Web 27 May 2011.
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