[Gk. phone, a sound ; and graph-ein, to write.] The phonograph, invented by Mr. Edison in 1877, is an instrument which mechanically records and reproduces articulate human speech, song, etc. Speaking in front of this instrument, a thin iron plate having a blunt steel point or pen fixed at its centre is made to made to vibrate ; the steel point by means of an ingenious mechanism, chronicles the vibratory movements by indenting a sheet of tin-foil, wax, or paraffin, with which it is brought into contact. The slip thus marked is then removed, and may be sent to any distance, or kept for a number of years, when it has only to be placed on a similar phonograph, and the operations reversed, in order to produce similar vibrations, which exactly reproduce the voice and the words originally spoken. The message can be read off as often as desired, until the indentations are worn out.