 | Nehemiah Hawkins - 1910 - 570 páginas
...during his experimenting then, he devised an arrangement of batteries and electromagnets embodying the principle of the telegraph relay which made possible...which he held until his death. As chairman of the BS Lighthouse Board he made important tests in marine signals and lights. In meteorology, terrestrial... | |
 | Nehemiah Hawkins - 1915 - 536 páginas
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 | 1921 - 1066 páginas
...during his experimenting then, he devised an arrangement of batteries and electromagnets embodying the principle of the telegraph relay which made possible....discharges (1842), and other electrical phenomena. Henry enjoyed an international reputation, and is acknowledged to be one of America's greatest scientists.... | |
 | 1922 - 878 páginas
...considerable distance; in other words, he discovered the essential phenomena of wireless telegraphy. In 1846 he was chosen secretary of the Smithsonian Institution at Washington, a position that he held until his death, on May 13, 1878. In 1849 he was elected president o"f the... | |
 | Frank Duncan Graham - 1941 - 598 páginas
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 | Frank Duncan Graham - 1941 - 1376 páginas
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... telegraph practice. He was made a professor at Princeton in 1832, and during his experimenting then, he devised an arrangement of batteries and electromagnets embodying the principle of the telegraph relay which made possible long distance transmission.... 