| ELECTRICAL REPRODUCTION OF SOUND|
| 1875 ||The telephone was invented by Alexander Graham Bell.|
| 1877 ||Music was transmitted by Bell from Boston to Salem.|
| 1877 ||The phonograph was invented by Thomas A. Edison, and
demonstrated in 1878.
| 1892 ||Telephone service was opened from New York to Chicago; in|
1911, to Denver; in 1915, to San Francisco.
| 1915 ||Experimental radio telephone messages from Arlington heard|
| 1918 ||Radio telephony to airplanes.|
| 1920 ||Radio broadcasting, Station KDKA; 1922, WEAF|
| 1924 ||Electrically cut phonograph records.|
| 1926 ||First commercial sound pictures.|
| 1927 ||Commercial radio-telephone service, New York to London.|
| 1933 ||Stereophonic reproduction of music transmitted over telephone|
wires, Philadelphia to Washington.
| 1935 ||Stereophonic reenforcement of music, Hollywood Bowl.|
| 1936 ||Demonstration of stereophonic reproduction of recorded music|
to membership of Academy of Motion Picture Arts and Sciences
and Society of Motion Picture Engineers.
| 1940 ||Stereophonic reproduction of recorded music, New York and|
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