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 349
Figure 73. — Reproduction of Hughes micro- phone. {USNM 315083-4.) telephone patents of inventors like Elisha Gray and Amos Dolbear 53 (see fig. 68), but had hired Thomas A. Edison to invent a new transmitter. As will be seen below, the new American Speaking Telephone Company ceased giving…
Science
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
