THE CAMERA.
For photomicrography the camera is either an extending or bellows camera, or a non-extending or box camera ; this is supported on a stand which is attached to a base board. The base board is 1 to 5 ft. long, about 10 in. wide, and to 1 in. thick. The base board is constructed to hold all the apparatus required—camera, microscope, and illuminant. Generally the camera is made to slide upon rails, and can be clamped in any position ; in the bellows form the back of the camera may be moved while the front is fixed, thus allowing of extension. The microscope is clamped in position, and it and the illu minant are by preference fitted upon a separate stage made to revolve, so that it can readily be placed at right angles to the camera for bringing the object into view and focussing it. Both horizontal and vertical cameras are used ; the former are more general, but the latter will he found indispensable for certain classes of work ; for instance, in photographing ob jects temporarily mounted in water, animalcula., etc., which would not remain
in the field of view- if placed upon the stage when the tube of the microscope was in the horizontal position.
position, and it is conneeLeu to a hori zontal camera capable of extending to :;6 in. Fig. 076, p. 514, shows the illuminat ing apparatus for a first-class photomicro graphic outfit, consisting of an electric lamp enclosed in a lantern, and a portion of the so-called " optical bench " of Zeiss is seen. This consists of a triangular prismatic rail, which is fixed to the base board, and upon which the condensers, light modifiers, etc., are made to slide on " saddle" feet, and may be clamped in the most suitable positions. The appara tus shown by Fig. 72S is a very useful one, because it can be fixed either in the hori zontal or vertical positions ; while Fig. 729 is a vertical camera sliding upon a metal rod. A useful yen ical camera is that designed by Dr. Van Huerck (Fig.