For drawing eye-piece No. 93 and the Abbe drawing apparatus the surface of the drawing board should be horizontal.
Drawing apparatus after v. Tubeuf.
| No. 97. | The drawing apparatus after v. Tubeuf serves for drawing objects from nature. By means of a prism mounted in a metal box, the object is reflected into the eye in such a manner that its image appears erected on the drawing surface. This is quite an advantage when drawing from nature but is unimportant when using a drawing apparatus on the microscope. Two smoked glasses mounted in moveable metal arms serve to moderate the intensity of the light. On the side of the prism nearest the eye is a small wheel diaphragm attached to regulate the size of the opening. The apparatus is mounted on a heavy nickel-plated stand with vertical and lateral adjustments controlled by thumb-screws | $12.— |
Mechanical Stages.
Mechanical stage No. 98.
| No. 98. | Mechanical stage adapted to Stands I, Ia and Ib. The stage is
readily attached to the microscope by means of a small screw,
C, which screws into a thread in the microscope just behind its
stage, and binds the mechanical stage firmly in position and
always in the same position. It may be again removed by simply
unscrewing this set screw. The movements of the stage are at right angles to one another, are accomplished by carefully constructed rack and pinion adjustments and the exact position of each adjustment is indicated by vernier scales. The extent of the lateral movement is 50 mm; that of the other 30 mm. This stage permits the careful and systematic examination of large specimens and its construction is so perfect that by means of the vernier scales the most minute objects may be readily replaced in the field of vision, even after removal and readjustment of the stage, provided only that their location when in the field of vision as indicated by the scales had been noted | $28.— |
| No. 99. | Large mechanical stage for stand, A, adapted for slides 50×100 mm; both movements by rack and pinion adjustments | $32.— |