it was necessary that for such work the relatively heavy and expensive electric motor should be discarded, and a simple spring motor constructed with a sufficiently sensitive governor to permit accurate musical reproduction. Such a motor was designed, and is now used on all phonographs except on such special instruments as may be made with electric motors, as well as on the successful apparatus that has more recently been designed and introduced for stenographic use. Improved factory facilities were introduced; new tools were made, and various types of machines were designed so that phonographs can now be bought at prices ranging from $10 to $200. Even with the changes which were thus made in the two machines, the work of developing the business was slow, as a demand had to be created; and the early prejudice of the public against the phonograph, due to its failure as a stenographic apparatus, had to be overcome. The story of the phonograph as an industrial enterprise, from this point of departure, is itself full of interest, but embraces so many details that it is necessarily given in a separate later chapter. We must return to the days of 1878, when Edison, with at least three first-class inventions to his credit--the quadruplex, the carbon telephone, and the phonograph--had become a man of mark and a "world character." The invention of the phonograph was immediately followed, as usual, by the appearance of several other incidental and auxiliary devices, some patented, and others remaining simply the application of the principles of apparatus that had been worked out. One of these was the telephonograph, a combination of a telephone at a distant station with a phonograph. The diaphragm of the phonograph mouthpiece is actuated by an electromagnet in the same way as that of an ordinary telephone receiver, and in this manner a record of the message spoken from a distance can be obtained and turned into sound at will. Evidently such a process is reversible, and the phonograph can send a message to the distant receiver. This idea was brilliantly demonstrated in practice in February, 1889, by Mr. W. J. Hammer, one of Edison's earliest and most capable associates, who carried on telephonographic communication between New York and an audience in Philadelphia. The record made in New York on the Edison phonograph was repeated into an Edison carbon transmitter, sent over one hundred and three miles of circuit, including six miles of underground cable; received by an Edison motograph; repeated by that on to a phonograph; transferred from the phonograph to an Edison carbon transmitter, and by that delivered to the Edison motograph receiver in the enthusiastic lecture-hall, where every one could hear each sound and syllable distinctly. In real practice this spectacular playing with sound vibrations, as if they were lacrosse balls to toss around between the goals, could be materially simplified.