at A1 B1, Fig. 82. (This arrangement was shown by Deprez before Baudet adopted it for his motor, as will have been already seen.) At the departure station FIG. 82. B ALIX is a sort of commutator A B, sending along the line a series of currents alternately reversed. Theory shows and experiment proves that the motor then reproduces with perfect exactitude the movements of the commutator, even for the highest speeds. Trouvé principally endeavoured to apply his motor to locomotion. He constructed before the Exhibition of 1881 an electric velocipede with favourable results; it was less interesting than the boat he put on the Seine, and which was worked on the little lake at the Exhibition. For this he made use of a small double motor, that is to say, two bobbins put close together, fixed on the rudder-head. The movement was communicated by means of an endless chain to a small screw fitted in the rudder itself, which was very handy for steering. The electricity was produced by a bichromate of potash battery in the middle of the boat, and brought to the motor by two flexible cables, which served at the same time for yoke lines. The whole was light and worked well. The general appearance is represented in Fig. 85, and it was possible by this means to go at the rate of 1 metre per second (about 3 miles an hour). In the battery used the plates were attached to a small winch, so that they could be raised or lowered into the liquid as desired. The battery therefore was only at work when wanted, and Fig. 84 shows its general arrangement. Trouvé has also constructed other arrangements of this motor, as applied to navigation, and where the boat requires considerable motive power he places the motor in the boat itself, so that it acts directly on the screw shaft. Another application of this same motor was shown at the Exhibition of 1881. It was employed to work a pianista. A pianista is a sort of mechanical key-board, worked by compressed air, and fixed to an ordinary piano. By feeding the instrument with sheets of card-board pierced with holes, and passing them through by means of a handle, the apparatus works levers which drop on the notes and perform a tune. The electric motor was employed to turn the handle, which it is rather tedious to work by hand. That which was applied to the pianista in the Exhibition, which we give in Fig. 86, was of such small dimensions that it was able to be fitted to the side of the apparatus without causing any inconvenience, and was very well adapted by Journaux, who has also applied Trouvé's motor to his sewingmachines. The pianista was worked by six Faure |