Parallel Motion Devices.—A form of suspension favored by the French consists of parallel bell cranks, rigidly linked together and held up by springs. Mountings of this sort are illustrated in Figs. [86], [87], [88] and [96]. The guiding principle is that any sort of shock will be transformed into a straight up-and-down or side-wise motion of the camera, which is harmless. The mounting as adapted by the English surrounds the camera body, making the plane of support somewhere near the center of gravity. In certain of the French suspensions employing this principle the whole camera is hung below the bell cranks (Fig. [86]), and then the nose is restrained by heavy rubber bands. The net result is largely a matter of adjustment.
Fig. 85.—Tennis ball suspension, assisted by elastic bands attached to nose of camera.
Fig. 86.—French spring and bell crank suspension.
Fig. 87.—U. S. hand-operated 18 × 24 centimeter plate camera on bell crank mount with rotating turret.
Fig. 88.—Same camera in plate changing position.
