The Current in a Dynamo or Motor.—This brings us to the production of an electric current by the dynamo. In the dynamo we have a coil of wire moving across a magnetic field, alternately passing into this field and out of it. A magnetic field is produced, as we have just seen, by the steady movement of electrons, and we may picture it as being a region of the ether disturbed or strained by the effect of the moving electrons. When the coil of wire passes into the magnetic field, the electrons of its atoms are influenced powerfully and set in motion in one direction, so producing a current in the coil. As the coil passes away from the field, its electrons receive a second impetus, which checks their movement and starts them traveling in the opposite direction, and another current is produced. The coil moves continuously and regularly, passing into and out of the magnetic field without interruption; and so we get a current which reverses its direction at regular intervals, that is, an alternating current.
THE TELEGRAPH AND ITS WONDERFUL INSTRUMENTS
THE MORSE DIRECT INKING PRINTER
THE MORSE SOUNDER
| A | . _ | J | . _ _ _ | S | . . . | 2 | . . _ _ _ |
| B | _ . . . | K | _ . _ | T | _ | 3 | . . . _ _ |
| C | _ . _ . | L | . _ . . | U | . . _ | 4 | . . . . _ |
| D | _ . . | M | _ _ | V | . . . _ | 5 | . . . . . |
| E | . | N | _ . | W | . _ _ | 6 | _ . . . . |
| F | . . _ . | O | _ _ _ | X | _ . . _ | 7 | _ _ . . . |
| G | _ _ . | P | . _ _ . | Y | _ . _ _ | 8 | _ _ _ . . |
| H | . . . . | Q | _ _ . _ | Z | _ _ . . | 9 | _ _ _ _ . |
| I | . . | R | . _ . | 1 | . _ _ _ _ | 0 | _ _ _ _ _ |
THE MORSE TELEGRAPH CODE FOR LETTERS AND FIGURES
