12,529. Dahl, H. June 19. Speed indicators.-The head f of a piston e, under a spring d in a radial cylinder b upon a rotating disc a, completes electric circuits containing indicators as it passes between pairs of parallel spring strips at different distances from the centre of the disc. The holders k of the springs may have radial and axial adjustment, and the springs may be replaced by spring buffers bearing inlaid contacts. In a modification, the contacts are in the cylinder, and are wired to fingers touching collars on the shaft.