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Dead medium: Phonautograph and Barlow's Logograph
From: George.Raicevich@nal.gov.au (George Raicevich)

Source(s):
John Aldred: http://www.amps.net/newsletters/23_record.htm;
http://sun1.phy.cuhk.edu.hk/Q_A/Wave/Q97-196E;
Knight's American Mechanical Dictionary, in "Telephone", p.2514. (1880: Riverside Press, Cambridge);
http://www.indiana.edu/~ctwardy/AGB/V1/phonautograph.html; American Journal of Science and Arts," August, 1874, pages 130, 131

Phonautograph

The ancient Greeks knew that sound as heard by the ear consisted of vibrations of air which, at certain frequencies, could even cause objects to vibrate. Records indicate that resonating panels were commonly used to improve the acoustics of Greek theatre. Back in the year 18 BC even the Romans installed large metal vases in their amphitheatres, specially tuned to vibrate at certain frequencies. But it was not until 1857 that the first instrument for recording these vibrations was patented by Frenchman Leon Scott. He called his invention the 'Phonoautograph'.

The recording medium was a piece of smoked paper attached to the surface of a drum which, when rotated, moved forwards along a helical screw. A stylus was attached to a diaphragm through a series of levers, which moved in a lateral direction when the diaphragm was vibrated by a voice. This caused a wavy line to be traced on the smoked paper. A barrel shaped mouthpiece was also included in the design. This was purely a device for accurately displaying sound waves, and it was not the inventor's intention to playback a recording.

The Phonoautograph promoted a flurry of activity by inventors in many countries, but it was another twenty years before Thomas Edison brought out his epoch making 'Phonograph' in 1897 which could record as well as play back. Scott's smoked paper was replaced by tin foil, and the stylus was attached directly to the diaphragm to trace a recording of variable depth (hill and dale). In subsequent models the tin foil was replaced by a wax cylinder which continued to be used for many years, Edison cylinders were finally discontinued around 1928.

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In 1857, Leon Scott invented the phonautograph. His design consisted of a barrel-shaped plastic speaking horn. The upper end was left open, while the lower end was fitted with a brass tube, across which was stretched a flexible membrane. A stiff pig's bristle was attached to the outside of the membrane to act as a stylus or pen. A smoked-paper cylinder was rotated beneath the pig's bristle. When sounds were directed into the horn, both the membrane and bristle moved back and forth, tracing the waveform as a wavy line on the cylinder. Nevertheless, this design CANNOT reproduce sound.

Later, Thomas Edison's invention consisted of a membrane to which was fastened a steel stylus (that is, the needle in your question) and a cylinder covered with tinfoil. First, the membrane recorded sound as in Leon Scott's phonautograph, making a series of spiral "hill-and-dale" grooves in the foil surface. When the stylus was made to travel over the grooves , it made the membrane vibrate in response to the depressions in the grooves. Hence, the motion of the stylus can create the original sound.

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Barlow's Logograph

Articulate sounds are accompanied by the explusion of air from the mouth, which impulses vary in quantity, pressure, and in the degree of suddennes with which they commence and terminate.

An instrument which will record these impulses has been termed by its inventor, Lion Scott, a phonautograph, or phonograph, and by Mr. Barlow a logograph; the pressure of air in speaking is directed against a membrane which vibrates and carries with it a delicate marker, which traces a line on a traveling ribbon. The excursions of the tracer are great or small from the base line, which represents the quiet membrane, according to the force of the impulse; and are prolonged according to the duration of the pressure, different articulate sounds varying greatly in their length as well as in intensity; farther, another great difference in them consists in the relative abruptness of the rising and falling inflections, which make curves of various shapes, of even or irregular shape. The smoothness or ruggedness of a sound has thus its own graphic character, independent both of its actual intensity and its length.

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Barlow's logograph. . . consists of a small speaking-trumpet, having an ordinary mouth-piece connected to a tube, the other end of which is widened out and covered wtih a thin membrane of gold-beater's skin or gutta-percha. A spring presses slightly against the membrane, and has a light arm of aluminum, which carries the marker, consisting of a small sable brush inserted in a glass tube containing a colored liquid. An endless strip of paper is caused to traverse beneath the pencil, and is marked with an irregular curved line...