United States National Museum, Smithsonian Institution, United States. Department of the Interior · Washington : Smithsonian Institution Press, [etc.]; for sale by the Supt. of Docs., U.S. Govt Print. Off. · leaf 303
sary to signal over the line. With a needle galvanom- Figure 8. — Alexander’s telegraph in which a moving magnetic needle would uncover a eter and a larger battery than Barlow’s, Ritchie letter. From La Lumiere electrique, 1883, vol. 8, found that he could signal over a distance of several P- 333-…
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