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S. L., Oct. 5, 1886. 4°, 2 pagine ed una tavola. Margine superiore bianco consunto, strappetti senza perdita, macchie di ruggine, buona copia. Molto raro. "In 1882, Dolbear was able to communicate over a distance of a quarter of a mile without wires in the Earth. His device relied on conduction in the ground, which was different from later radio transmissions that used electromagnetic radiation. He received a U.S. patent for a wireless telegraph in March of that year. His set-up used phones grounded by metal rods poked into the earth. His transmission range was at least as much as a half a mile[2] and he received a patent for this device, U.S. Patent 350,299, in 1886. (He did not patent his system in Europe.)
In 1899, The New England Wireless Telegraph and Telephone Company, a subsidiary of the American Wireless Telephone and Telegraph Company, purchased Dolbear's 1886 patent, and filed a suit against Marconi for infringement. However, in March, 1901 a United States Circuit Court dismissed the suit. In April, 1902, American Wireless petitioned Congress to extend the 1886 patent by ten years, but was unsuccessful, so it duly expired on October 4, 1903.[5] In 1905, the New York Circuit Court further noted that the Dolbear patent was "inoperative, and that, even if operative, it operates by virtue of radically different electrical laws and phenomena" than the radio signaling used by Marconi." (https://en.wikipedia.org/wiki/Amos_Dolbear).

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