J. M. Benckert, of Philadelphia, has patented a machine for the above purposes. It consists in having a series of arms pivoted to a revolving plate, with weights at their outer ends, and their inner ends being connected with gearing. The arms are connected to a gearing cam, which is rotated reciprocally, as the arms, by centrifugal force and springs, are made to recede or approach each other ; the cam, as it thus rotates, giving the proper motion to an index, to designate the speed of the machine to which it is attached, and also actuating the throttle valve of a steam engine, or the gate of a water-wheel.