*ELECTRICITY AT THE WORLD'S FAIR.*

method of operation will be clearly understood from the diagrammatic sketch A (Fig. 6) and the illustration (Fig. 7) showing a diagram of the connections of the motor and generator circuits. Considering the latter first, M is the motor and G the generator. The armature A of the generator is wound with two sets of coils, B and B', brought out through the shaft and connected with the contact rings *b b* and *b' b'.* The field magnet of the motor consists of the iron ring R, also wound with two sets of coils, C C

and C' C', the diametrically opposite coils being connected together in series. The generator coils B and the motor coils C' C' it will be seen are included in one circuit L, and the remaining generator coils B' and the motor coils C C in another circuit L'. The armature of the motor consists simply of a disk of iron cut away at the sides, which becomes a magnet by induction when the motor field is energized. Turning to Fig. 6, B and B' represent the coils of the generator armature and C and C' those of the motor field as in Fig. 7. When the generator coils are in the position shown in the first diagram the coil B is generating no current and B' is generating its maximum amount. The coils C of the motor field, which are included in the circuit of B', are therefore traversed by their greatest current and produce magnetic poles in the iron ring R at N and S. As the generator armature revolves, B is brought to a position in which it is generating current, and when this movement amounts to one eighth of a revolution the circle will be in the position shown in the second diagram of the figure. Each of the pair of coils C and C' will now tend to set up poles in the ring R of the motor ninety degrees from each other, and as their action is equal and opposite, the position of the poles will be determined by the resultant of the magnetic forces acting on the ring, and the poles will therefore be shifted around