The manner of constructing and operating my invention is as follows: The entire apparatus is made of steel or iron, and the shaft, bearings, arms, springs and connecting-rods are of ordinary form. The main or driving pulley is cast with four hollow arms, in which round weights are inclosed, which move back and forth within the arms when the wheel is set in motion. The solid arms, as well as the hollow arms, which are used in addition to those forming a part of the driving-pulley, are arranged by means of set-screws a suitable distance apart upon the axis and in different perpendicular planes, so as to give steadiness in motion. A thread is cut upon each end of these arms, and the fixed weights are then screwed on. When the shaft or axis revolves, the weights which move toward the ends of the arms above the center accelerate the motion, and the momentum of the machine aids in overcoming the resistance caused by the weights, which are below the center. At the same time the revolution of the eccentric and crank-pin upon the axis depresses the connecting-rods, which in turn depress the springs, which, being released as soon as the eccentric and crank-pin have reached their lowest point, contribute a lifting power to overcome the resistance above mentioned. As shown in the drawings, these springs joined to the connecting-rods may be supported and assisted by other springs. The power is applied by hand, operating upon a crank at the end of the axis, or may be imparted by steam, hot air, electricity, or in any other known method, and is conducted to any desired point by means of the belt _b_. Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is: 1. The combination, in apparatus for increasing mechanical power, of an axis, as A, supported upon bearings N, with a driving-pulley, as B, having hollow arms, as C, with movable weights, as _a_, and radial arms, both solid and hollow, the latter having movable weights, together with fixed weights attached to the end of each arm, all substantially as and for the purpose described. Ferguson's Device James Ferguson was an eminent Scotch mechanician and astronomer. He was born in 1710, and died in 1776. He was reared in very humble circumstances, and is known as the Peasant Boy Philosopher. A most interesting story of his life was written by Henry Mayhew, and published in England in 1857, entitled "The Story of the Peasant Boy Philosopher." He prepared astronomical tables of great value and lectured on astronomical and mechanical subjects. His lectures were edited by a no less eminent man than Sir David Brewster. [Illustration]