Phonograph

An apparatus for reproducing articulate speech. It is not electric, except as it may be driven by electricity. It consists of a cylinder of wax-like material which is rotated and moved slowly, longitudinally, screw fashion, at an even speed. A gla diaphragm carrying a needle point is supported with the point barely touching the wax. If the diaphragm is agitated, as by being spoken against, the needle is driven back and forwards cutting a broken line or groove following the direction of the thread of a screw in the wax, the depth of which line or groove continually varies. This imprints the me age. If the needle is set back and the cylinder is rotated so as to carry the needle point over the line thus impre ed, the varying depth throws the needle and diaphragm into motion and the sound is reproduced. The cylinder is rotated often by an electric motor, with a centrifugal governor. [Transcriber's note; Due to T. A. Edison, 1877, fifteen years before this book.]