Fig. 169.—Microscope in position for drawing.
Fig. 170.—Beale’s Neutral Tint Reflector.
The position in which the microscope must be placed is shown in the accompanying illustration ([Fig. 169]).
Beale’s neutral tint reflector ([Fig. 170]) is much in use, and its advantages are utility, simplicity, and inexpensiveness.
Fig. 171.—The Abbe Model Camera Lucida.
The Abbe model of camera lucida has been brought into use because the projected image can be better illuminated, and is consequently so much brighter. This form is now made in aluminium by Messrs. Watson & Sons. In place of the image being traced by projection on paper, the reverse is the case, both the paper and pencil are projected into the field of view. The mirror reflects the paper on to the silvered surface of a prism placed over the eye-lens of the eye-piece of the microscope, and it is thereby conveyed to the eye. There is a central opening in the silvering through which microscopic vision is obtained. It is fitted in a new manner by means of a cloth-lined adapter, fitting over the outside of the microscope tube; this saves all trouble in centring and ensures concentricity. Where the instrument has capped eye-pieces, the camera lucida must be adapted to the eye-piece, the cap being removed. The apparatus can be disconnected from the fitting adapter by means of a sliding pin, and readily replaced, or can be lifted over out of the way, as shown in the drawing. Being made almost entirely in aluminium it is very much lighter than other forms of apparatus, and does not cause vibration. It can be used with the microscope at any angle, the only necessity being that the paper on which the sketch is made should be kept at the same angle as the instrument.