The application of this power to the telegraph is original with me. If the electro-magnet is now used in Europe for telegraphic purposes, it has been subsequently introduced. All the systems of electric telegraphs in Europe from 1820 to 1840 are based on the deflection of the magnetic needle, while my system, invented in 1832, is based, as I have just observed, on the electro-magnet....
"Why not an electrical telegraph?" he asked himself. His idea seems to have been that the electric current could carry different notes over the wire and reproduce them by means of the electro-magnet. Although Bell did not know it, many others were struggling with the same problem, the answer to which proved most elusive. It gave Bell a starting-point, and the search for the telephone began.
Be able to make a simple electro-magnet, have elementary knowledge of action of simple battery cells, and the working of electric bells and telephone. Understand and be able to remedy fused wire, and to repair broken electric connections. Engineer: A scout must have a general idea of the working of motor cars and steam locomotives, marines, internal combustion and electric engines.
They promised all the necessary materials; also that they would get ready to receive the pirate once he was finally brought in to them. It was nearer an hour and a quarter later that the machine fell to the great San Francisco landing field, where the mechanics at once set to work bolting a huge electro-magnet on the landing skids on the bottom of the machine.
We have, first, our electric lamp, then a Nicol prism, to polarize the beam emergent from the lamp; then an electro-magnet, then a second Nicol, and finally our screen. At the present moment the prisms are crossed, and the screen is dark. I place from pole to pole of the electro-magnet a cylinder of a peculiar kind of glass, first made by Faraday, and called Faraday's heavy glass.
Down sped the little, netted cube, whirling in the sunlight. Its speed was almost that of a rifle-ball so far in excess of anything that could have been produced by gravitation as to suggest that some strange, magnetic force was hurling it earthward, like a metal-filing toward an electro-magnet. It dwindled to nothing, in a second, and vanished. All peered over the rail, eager with anticipation.
A mouthpiece was arranged to throw the sounds of the voice against the diaphragm, and as the membrane vibrated the bit of iron upon it acting as an armature induced currents corresponding to the sound-waves, in the coils of the electro-magnet. Passing over the line the current entered the coils of the tubular electro-magnet in the receiver. A thin disk of soft iron was fastened at the end of this.
This current affects an electro-magnet one for each shaft at the receiving end, and each of these magnets, when the current is on, attracts an armature bearing a pawl, which, being lifted, allows the notched wheel, upon which it bears, to turn to the extent of one notch.
He wound a U-shaped piece of soft iron with insulated wire, and made it an electro-magnet, and placed the north end of the magnetized bar between the two legs of this electro-magnet.
Soon after his return to London, by the end of April, he had two simpler instruments in working order. All these preparations had already cost him nearly four hundred pounds. On February 27, Cooke, being dissatisfied with an experiment on a mile of wire, consulted Faraday and Dr. Roget as to the action of a current on an electro-magnet in circuit with a long wire. Dr.