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However, we find in Morse's report, on page 10, the following: "In 1825, Mr. Sturgeon, of England, made the first electro-magnet in the horseshoe form by loosely winding a piece of iron wire with a spiral of copper wire. In the United States, as early as 1831, the experimental researches of Professor Joseph Henry were of great importance in advancing the science of electro-magnetism.
In the center of the hollow part is placed a vertical electro-magnet, one of the wires of which communicates with one of the poles of the pile, and the other with a flat metallic circle glued to the cover of the table. Beneath this circle, and at a slight distance from it, there is a toothed circle, F, connected with the other pole of the pile.
There were wires suspended in the room running from one end of it to the other, and returning many times, making a length of seventeen hundred feet. The two ends of the wire were connected with an electro-magnet fastened to a vertical wooden frame.
The use of a core of soft iron, magnetized by the passage of a current through a helix of wire wrapping it as the thread does a spool, is the indispensable feature, in some form meaning the same thing, with the same results, in all machines that are given movement to by an electric current. This is the electro-magnet.
He began his researches in 1874 with a musical telephone, in which he employed the interrupted current to vibrate the receiver, which consisted of an electro-magnet causing an iron reed or tongue to vibrate; but, while trying it one day with his assistant, Mr. Thomas A. Watson, it was found that a reed failed to respond to the intermittent current. Mr.
In a short time he returned with a tractor-like machine equipped with a small derrick, designed to get its power from the electric mains. He ran the machine over to the ship. The others looked up as they heard the rumble and hum of its powerful motor. From the crane dangled a strong electro-magnet. "What's that for?" asked Wade, pointing to the magnet.
Almost at once began a series of brilliant experiments in electricity which have linked his name with that of Benjamin Franklin as one of the two most original investigators in that branch of science which this country has ever produced. His first work was the improving of existing forms of apparatus, and his first important discovery was that of the electro-magnet.
Although it was known that inductive action travelled with finite velocity in space, and that an electro-magnet would affect the space about it practically inversely as the square of the distance, and that such phenomena as are involved in telephonic induction between circuits could have no other meaning than the one assigned by Maxwell, yet nearly all the physicists failed to form the only conception of it that was possible, and waited for Hertz to devise apparatus for producing interference before they grasped it.
Be this as it may, he devised a receiver, consisting of a stretched diaphragm or drum of this material having an armature of magnetised iron attached to its middle, and free to vibrate in front of the pole of an electro-magnet in circuit with the line.
This was stretched tight to form a sort of drum, and an armature of magnetized iron was fastened to its middle. Thus the bit of iron was free to vibrate, and opposite it was an electro-magnet through which flowed the current that passed over the line. This acted as the receiver. At the other end of the wire was a sort of crude harmonica with a clock spring, reed, and magnet.
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