Fig. 95.—Zeiss’s Medium Stand Microscope.
The medium tube-length of the microscope is 160 mm. from the attachment of the objective to the eye-piece end. The draw-tube admits of the length being increased or diminished, and this may be read off by means of the millimetre scale engraved on the tube. My description of this model also applies to the higher class microscopes, which will be found in every way well finished and adapted to biological and scientific research.
Fig. 96.—E. Leitz’s Medium-sized Microscope.
E. Leitz’s of Wetzlar Microscopes.—This optician publishes a series of twelve high-class forms of instruments. By preference, the horse-shoe form of stand ([Fig. 96]) is adopted in the whole of this maker’s models, the body being supported on a hinge joint and clamped over, and fitted with a circular revolving centred mechanical stage, attached to the ordinary stage by means of a set pin, which fixes the stage in position. By removing the screw, the stage can be detached; in this way, the stage serves for searching over large surfaces and registering the results.
Fig. 97.—Leitz’s Dissecting Microscope.
The coarse adjustment is made by rack and pinion, and the fine adjustment by micrometer screw, the head of which is provided with a scale reading 1⁄100 mm. The draw-tube is also cut and ruled to millimetre scale. The sub-stage has rack and pinion movement, and is arranged for the Abbe condenser and iris diaphragm. This is attached to the upper stage by means of a set pin, which fixes and retains it in position after perfect centring. By removing the pin, the sub-stage can be either detached or swung aside by pressing a button. In short, this microscope is in all respects well furnished and fitted with the requisite complex mechanism necessitated by modern high-class technicological work.
Leitz’s students’ microscope, with sliding body, micrometer screw fine adjustment, concave mirror, two eye-pieces and two objectives, ¾ inch and 1⁄8 inch, in mahogany case, costs £3 10s. Leitz’s dissecting microscope, with a heavy foot and rests, is fitted with two aplanatic lenses, magnifying × 10, × 20 diameters.