Modern Magic: A Practical Treatise on the Art of Conjuring

CHAPTER II. KEMPELEN. Kempelen’s Speaking Machine has been thus described. It was of simple structure, and consisted only of five parts--viz., the reed, representing the human glottis; an air-chest, with internal valves; the bellows or lungs; a mouth with its appurtenances, and nostrils formed to resemble those of the human body. The reed was not cylindrical, but formed to imitate the reed of a bagpipe drone. The hollow portion, however, was square, and the tongue of the reed, which vibrated, consisted of a thin ivory slip resting upon it horizontally. This hollow tube was inserted into the chest, and the discharge of air occasioning a vibration of the ivory, the requisite sound was produced. To soften its vibration, the part supporting the slip was covered with leather, and a movable spring shifting along the upper side of the slip brought the sound of the reed to the proper pitch. The sound was more acute as the spring was moved forward to the outer extremity, because the vibrations then became quicker, and when shifted farther from the anterior extremity, the sound became more grave, as the vibrations were then slower. A slight curvature of the ivory slip arose from the pressure of the spring, which was enough for the object desired. One end of the air-chest, which was of an oblong figure, received this voice-pipe, containing the reed; and into the opposite end was inserted the mouth of the bellows.