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Edison's Phonograph

front of this, and is reflected through two lenses to the receiving station, which may be several hundred feet, or metres, away. The operator stands behind the mirror, and speaks against the back of it. At the receiving-station is a reflector arranged to receive the beam of light and concentrate it upon a curious substance discovered a few years ago, and called celenium, and connected in a peculiar manner with a telephone. Now, if the operator speaks behind the mica mirror, the person holding the telephone to his ear hears every word that is said. To trace the curious changes the sound goes through, from one operator to the other, we must observe that the vibrations of the air move the mirror, and cause the beam of reflected light to vibrate. The vibrations of the light affect the electrical condition of the telephone; the electrical vibrations are transformed in the telephone back again into sounds. This truly wonderful invention is so new that it is impossible to say what may result from it. This much has, however, been proved: the sound of the human voice and musical notes may be sent to a distance by means of a beam of sunlight or by the light of a lamp. EDISON'S PHONOGRAPH. - The phonograph, or sound-recorder, is a device for permanently recording and faithfully reproducing at any time or place all kinds of sounds, including those of the human voice. The speaking phonograph was invented by Mr. Thomas A. Edison, and is a purely mechanical invention, no electricity being used. It is, however, somewhat allied to the telephone, in consequence of the fact that, like the latter, its action depends upon the vibratory motions of a metallic diaphragm, capable of receiving from and transmitting to the air sound vibrations. When a person speaks into the mouth-piece of the instrument, which will cause the diaphragm to vibrate, and as the vibrations of the latter correspond with the movements of the air producing them, soft and yielding tinfoil will become marked along the line of the groove by a series of indentations of different depths, produced by a peculiar mechanical combination, varying with the amplitude of the vibrations of the diaphragm, or, in other words, with the inflections or modulations of the speaker's voice. These inflections may therefore be looked upon as a sort of visible speech, which, in fact, they really are. If, now, the diaphragm is removed, and a cylinder turned, we have only to replace the diaphragm and turn in the same direction as at first to hear repeated all that has been spoken into the mouth-piece of the apparatus. A stylus by this means being caused to traverse its former path, and consequently rising and falling with the depressions in the foil, its motion is communicated to the diaphragm, and thence through the intervening air to the ear, where the sensation of sound is produced. ELECTRIC LIGHT. - Since 1877 the subject of utilizing the recently discovered powers of electricity as an illuminating agent,