OPTICAL, SCIENTIFIC AND MECHANICAL INSTRUMENTS-NAMELY, SPECIAL PURPOSE MICROSCOPES INCLUDING CLOUD CHAMBER MICROSCOPES AND MASK ALIGNING MICROSCOPES, PHOTOMICROGRAPHIC MICROSCOPES WITH AND WITHOUT CAMERA MOUNTS AND REMOTE POSITIONING DEVICES FOR REMOTELY POSITIONING SMALL PARTS OR PORTIONS THEREOF FOR VISUAL OBSERVATION FOR PHOTOGRAPHING THROUGH A MICROSCOPE OPERATED EITHER ELECTRICALLY OR MECHANICALLY