the phases of the generator and ring at three-quarters of a revolution, and Figures 8 and 8a those at seven-eights of a revolution of the generator armature. These Figures will be readily understood from the foregoing.
When a complete revolution is accomplished, the conditions existing at the start are reestablished and the same action is repeated for the next and all subsequent revolutions, and in general, it will now be seen that every revolution of the armature of the generator produces a corresponding shifting of the poles or lines of force around the ring.
This effect is utilized to produce the rotation of a body or armature in a variety of ways. For example, applying the principle above described to the apparatus shown in Figure 9: the, disk D owing to its tendency to assume that position in which it embraces the greatest possible number of magnetic lines, is set in rotation following the motion of the lines or the points of greatest attraction.
The disk D in Figure 9, is shown as cut away on opposite sides, but this will not be found essential to its operation, as a circular disk, as indicated by dotted lines, would also be maintained in rotation. This phenomenon is probably attributable to a certain inertia or resistance inherent in the metal to the rapid shifting of the lines of force through the same, which results in a continuous tangential pull upon the disk that causes its rotation. This seems to be confirmed by the fact that a disk of steel is more effectively rotated than
