ISBN: 9781522904045 - first principles of natural philosophy (1897) (7 Ergebnisse)

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Paperback. Zustand: new. Paperback. Amos Emerson Dolbear (November 10, 1837 - February 23, 1910) was an American physicist and inventor. Dolbear researched electrical spark conversion into sound waves and electrical impulses. He was a professor at University of Kentucky in Lexington from 1868 until 1874. In 1874 he became the chair of the physics department at Tufts University in Medford, Massachusetts. In 1899 one of his patents was purchased in an unsuccessful attempt to interfere with Guglielmo Marconi's activities in the United States.Dolbear was a graduate of Ohio Wesleyan University, in Delaware, Ohio. While a student at Ohio Wesleyan, he had made a "talking telegraph" and invented a receiver containing two features of the modern telephone: a permanent magnet and a metallic diaphragm that he made of a tintype. He invented the first telephone receiver with a permanent magnet in 1865, 11 years before Alexander Graham Bell patented his model. Later, Dolbear couldn't prove his claim, so Bell kept the patent. Dolbear lost his case before the U. S. Supreme Court, (Dolbear et al. v. American Bell Telephone Company). The June 18, 1881 edition of Scientific American This item is printed on demand. Shipping may be from our UK warehouse or from our Australian or US warehouses, depending on stock availability.…