. Bulletin. Science. Figure 70.—Reproduction of Berliner's toy drum microphone. The contact was a needle that pierced a drum membrane against which a metal ball rested. {USNM 3og277; Smith- sonian photo ^^Gy.) Figure 71.—Drawing from one of Edison's basic microphone patents, showing the use of a semiconductor as one of the microphone contacts. From patent 474230 (May 3, 1892).. Figure 72.—Patent Office model of one of Edison's basic microphone patents, showing the use of multiple contacts. (USNM 2^2622; Smithsonian photo ^6yyy-A.) 326 BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY
. Bulletin. Science. Figure 70.—Reproduction of Berliner's toy drum microphone. The contact was a needle that pierced a drum membrane against which a metal ball rested. {USNM 3og277; Smith- sonian photo ^^Gy.) Figure 71.—Drawing from one of Edison's basic microphone patents, showing the use of a semiconductor as one of the microphone contacts. From patent 474230 (May 3, 1892).. Figure 72.—Patent Office model of one of Edison's basic microphone patents, showing the use of multiple contacts. (USNM 2^2622; Smithsonian photo ^6yyy-A.) 326 BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Smithsonian Institution; United States. Dept. of the Interior; United States National Museum. Washington, Smithsonian Institution Press, [etc. ]; for sale by the Supt. of Docs. , U. S. Govt Print. Off
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