. Collection of United States patents granted to Thomas A. Edison, 1869-1884 . Ca*e /53. PETERS. Photo-Lithographer, Wiuhmgton, D. C. United States Patent Office* THOMAS A. EDISON, OF MENLO PARK, NEW IN SPEAKING-MACHINES. Speeilieation forming part of Lelters Patent No. 201,700, dated March 20, 1>?8; application filed March 4,1878. To all whom it may concern: Be it known that I, Thomas A. Edison, ofMenlo Park, in the county of Middlesex andState of New Jersey, have invented an Im-provement in Speaking-Machines, (Case 153,)which I term the Aerophone, and of whichthe follow
. Collection of United States patents granted to Thomas A. Edison, 1869-1884 . Ca*e /53. PETERS. Photo-Lithographer, Wiuhmgton, D. C. United States Patent Office* THOMAS A. EDISON, OF MENLO PARK, NEW IN SPEAKING-MACHINES. Speeilieation forming part of Lelters Patent No. 201,700, dated March 20, 1>?8; application filed March 4,1878. To all whom it may concern: Be it known that I, Thomas A. Edison, ofMenlo Park, in the county of Middlesex andState of New Jersey, have invented an Im-provement in Speaking-Machines, (Case 153,)which I term the Aerophone, and of whichthe following is a specification. The object of this invention is to reproducethe human voice or other sounds with greatly-increased volume or force. Articulation produces certain atmosx>hericsound waves or vibrations in a given relationto each other in respect to volume or charac-ter. The sound-waves of words uttered in awhisper correspond generally to those utteredin the loudest tones, except in the volume. In my phonograph, heretofore secured byme, (Case No. 149,) the sound pro
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Keywords: ., boo, bookcentury1800, booksubjectinventions, booksubjecttelephone
