Word: electromagnets
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Dates: during 1920-1929
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...receiving set was hidden in the shallow top of the table, one leg of which was equipped as an aerial, another as a ground. The phenomena were produced by the activation of an electromagnet which attracted pieces of metal cleverly hidden in the performing objects. There was even a small piece of metal concealed in the bit of chalk which did the writing, directed by a telautograph...
...Joseph Henry, first a teacher in a boys' school, then professor of physics at Princeton, constructed the first real electromagnet, the first telegraph and printing telegraph, had a wireless set with which his family used to call him from the laboratory to his meals, and most important of all, discovered, jointly with Faraday, the laws of electromagnetic induction which underlie all electric power machinery. And when urged by his friends to press his claims for patent rights he answered that his scientific work was too important to be hampered by attending to such trivial matters...
...device records the fluctuations of this current by means of two wires of quartz, so fine that they are invisible even under a microscope, unless thrown into relief by light against a dark background. These wires are threaded across the magnetic field formed between the polar ends of an electromagnet. In each pole of the magnet is screwed a microscope, one lending light, the other enlargement. Rubber manacles are placed over the wrists of the patient. Under each manacle is a salt pad (electric conductor) from which a wire runs, bearing the current of the body to the quartz threads...
JOSEPH HENRY, inventor of the electromagnet, whose likeness was unveiled by Thomas A. Edison...