All the simpler devices failed, of course, to work. The more complicated devices are simply efforts to overcome the elementary principles that prevented the simpler devices from working. Among these that of Dixon Vallance (see page 34, ante), is best adapted to illustrate the folly and the fallacy of these various devices to overcome elementary principles. We here refer to the figure appearing on page 35, ante, shown in connection with Dixon Vallance's Device. The obvious purpose was to keep all the weights close to the hub, except those depended upon to produce continuous motion by their greater leverage. To the untrained and untechnical person it would perhaps not be manifest at first just why the Vallance machine failed to work. Here is its failure: Weight "c" must be raised toward the hub of the wheel. To raise that weight requires the application of force. That force must be supplied. The belt "cc" would work more freely if it were not elevating a weight, and the force required from "w" to turn the wheel so as to elevate the weight at "c" is counterbalanced by the resistance the weight "c" offers to being raised, and consequently to the motion of the belt and in turn to the progress of the wheel. It should always be remembered that, omitting friction, the energy exerted by a descending body is the _perpendicular distance_ of its descent multiplied by its weight. For, notwithstanding what its course may be from an elevated point to a lower point the energy accumulated in the descent is still the product of the perpendicular distance and the mass, or weight. In all of these devices it is apparent that every weight is brought back by some force from the lowest point it reaches to the same elevation from which it started to descend. It is axiomatic, therefore, that the perpendicular ascent is equal to the perpendicular descent. The ascending weight and the descending weight are, of course, the same. Therefore, the product of the weight and the perpendicular distance of _ascent_ is exactly equal to the product of the weight and the perpendicular distance of _descent_. Hence, there is an exact balancing of energies, and no motion results. Any motion imparted by wind, water or steam will, if the moving force be withdrawn, soon be overcome by unavoidable friction, and a state of rest follows. There can be no doubt that any attempt to attain Self-Motive Power by means of wheels, weights, levers, and the force of gravity must result in failure. The thing itself is physically impossible. In addition to what is above stated, read carefully Chapter XI, on Conservation of Energy; also read Chapter XIV, entitled "The Seeming Probability of Effecting a Continual Motion by Solid Weights in a Hollow Wheel or Sphere" at page 290 of this book. CHAPTER II DEVICES BY MEANS OF ROLLING WEIGHTS AND INCLINED PLANES Device by Mercury in Inclined Glass Tube and Heavy Ball on Inclined Plane