. Animal micrology; practical exercises in microscopical methods. Microscopy -- Technique; Microscopes -- Technique. FIG. 60.—Simple Camera, Lucida. FIG. 61.—Camera Lucida, Abbe. form a cube (Fig. 61). The lower one of the prisms is silvered along its cemented surface although a small central opening is left through which the object under the microscope may be viewed; connected with the cap is an arm which bears a mirror and this mirror may be so adjusted as to reflect the image of the drawing-paper on the table on to the prisms from one side. The prisms are so set that the silvered surface of
. Animal micrology; practical exercises in microscopical methods. Microscopy -- Technique; Microscopes -- Technique. FIG. 60.—Simple Camera, Lucida. FIG. 61.—Camera Lucida, Abbe. form a cube (Fig. 61). The lower one of the prisms is silvered along its cemented surface although a small central opening is left through which the object under the microscope may be viewed; connected with the cap is an arm which bears a mirror and this mirror may be so adjusted as to reflect the image of the drawing-paper on the table on to the prisms from one side. The prisms are so set that the silvered surface of the lower one reflects this image upward to the eye of the observer which also, co- iucidently, is viewing the magnified image of the object through the hole in the silvering. When proper adjustment of the light received from object and paper respectively is made, a pencil point may be distinctly seen when brought into the field of vision over the paper ; consequently, the outline of the object may be accurately traced. The secret of success in working with a camera lucida is to have the illumination in the two fields properly balanced. Small screens of tinted glass are provided with the instrument for such regulation. Low-power eyepieces should be used. With the Abbe camera lucida the microscope may be used in a vertical or in an inclined position. If the microscope stand is inclined, the drawing-board upon which the paper rests must have the same in- clination, or the outline when drawn will be distorted. Likewise, if the mirror of the camera is at any other angle than 45 degrees, an adjust- ment of the drawing-surface must be made; in short, the axial ray of the image and the drawing-surface must always be at right angles to pre- vent distortion. This means that if the mirror is depressed below 45 degrees the drawing-surface must be tilted toward the microscope twice as much as the mirror is depressed. For example, if the mirror is de- pressed to 37 degrees (8 below 45
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Keywords: ., bookpublisherchicagotheuniversityofchicagopress, bookyear1906
