PHONOGRAPH, an instrument for recording and reproducing sound. The instrument in its present stage of per fection has been evolved through ex tended laboratory work from the first principles that were demonstrated by a device invented in 1855 by Leon Scott. In Scott's instrument sound was collected by an ellipsoidal receiver, which was open at one end. A small tube was fastened to the other end of the receiver and a tightly stretched membrane to which a bristle was attached was fastened to the end of the tube. In front of the bristle was a cylinder surfaced with material sufficiently soft to take impressions from the bristle as the sound waves collected in the receiver caused the membrane to move the bristle; and at the same time the cylinder was made to move so that a record of the vibrations was made upon the soft surface of the cylinder.
In 1877 Charles Crass placed before the French Academy of Sciences a method of reproducing the fragile first cylinder by photoengraving on some harder surface and Konig of Paris made many changes and improvements on Scott's first machine.
Because of the great possibilities sug gested by the early laboratory models Thomas A. Edison started an intensive study of this field about 1877 and the real life of the phonograph began, al though his efforts were not concentrated in this field until a later date, and the machine to-day is a result of constant laboratory experimentation and improve ment.
Other names that should be mentioned in the development of the instrument are Bell and Tainter, who in 1885 invented the gramophone or machine which used a wax cylinder and a horizontal groove, and Emil Berliner who introduced the disk record in which the record of vibra tions was made in the horizontal in place of the vertical plane.
The modern machine consists essenti ally of a reproducer in which a metal stylus or jeweled point transmits the vibrations to some tightly stretched sur face; the vibrations are carried through an arm to a tone chamber. The record is revolved by a turntable which is ac tuated either by clockwork or an electric motor.
The fact that the early records, which were made of a composition which had wax as its principal ingredient, were fragile and would not wear well, led to experiments which would produce a more durable material. A method in which the original record is electroplated with gold and re-enforced with a less valuable material and used as a die which stamps the records into a plastic material which is afterward hardened is now used.
Almost every musical artist of note is under contract by one of the companies manufacturing phonograph records, and the industry of making phonographs and records has grown to tremendous size; many thousands of people are employed in the making, and a vast staff of research workers are engaged in mak ing studies which tend toward the im provement of the product. See GRAMO PHONE.