The speaking machine is of simple structure, and consists of only five principal parts. 1. The reed, representing the human glottis ; 2. An air chest, with internal valves ; 3. Bellows, or lungs ; 4. A mouth, with its appurtenances ; 5. Nostrils, as in the living subject. We shall not attempt to expa tiate on each of these parts, which would lead to a long discussion ; and in order to avoid this detail, we shall briefly explain, so far as we are able without figures, the general composition of each. The reed, though not cylindrical, is formed in imitation of the reed of a bagpipe drone, which probably many of those who peruse this article may have seen. The hollow portion, however, is square, and the tongue of the reed, which vibrates, consists of a thin ivory slip, resting upon it horizontally. This hollow portion, or tube, is in serted into the air chest ; and the discharge of air occasioning a vibration of the ivory, the requisite sound is produced. To soften the vibration, the part supporting the slip is covered with leather, and a moveable spring, shifting along the upper side of the slip, brings the sound of the reed to the proper pitch. The sound is more acute as the spring is moved for ward to the outer extremity, because the vibrations then become quicker; and if shifted farther from the anterior extremity, the sound becomes more grave, as the vibrations are then slower. The extremity of the ivory slip should not be applied close to the tube where it rests, but should remain a little open, that the air may penetrate and occasion the vibration. Thus we observe that a common bagpipe reed may be closed and produce no sound. A slight curvature of the ivory slip arises from the pressure of the spring, which is enough for the object desired.
One end of the air chest, which is of an oblong figure, receives this voice-pipe, as we shall call it, containing the reed ; and into the opposite cnd is in serted the mouth of the bellows. Both the apertures are guarded by leather, to prevent the unnecessary waste of air. Two smaller air chests are then put into it, each having a valve above closed by the pres sure of a spring, and each having a round aperture adapted to receive through the side of the large air chest a tin funnel, and a round wooden tube for producing hissing sounds as, s, z, sch, j. The voice-pipe is placed in the. large air chest, so as to be between the smaller air chests.
When all these parts are fitted to the air chest, the operation of one lever raising the valve of the first smaller chest connected with the tin funnel, sounds s; while the operation of another, raising the valve of the second smaller chest connucted with the wooden tube, sounds sch. But it is proper farther to explain, that, instead of being a simple funnel, it is in fact a tin box, with a square hole. in the outer end, nearly covered by a slip of pasteboard ; and the wooden tube is merely the mouthpiece of a com mon flute, closed at the lower extremity, and with the air-hole modified and contracted. The letter R
is produced by the rapid vibration of the ivory slip owing to a strong discharge of air.
M. Kempelen 's bellows, which are formed to . supply the place of lungs, have no peculiarities. He found that his machine requ red six times the quan tity of air used by a man in speaking. The noizle, as we have observed, is inserted into the large air chest, and the air which it discharges is also received by the small air chest.
With regard to the mouth, it consists of a funnel, or rather bell-shaped piece of elastic gum, applied to the air chest, and so adapted that the sound of the reed issues from it Elastic gum is selected for this purpose, as more nearly approaching to the natural softness and flexibility of the human organs. Independ ent of its communication with the reed producing the sound required, a tin tube connects it with the air chest, by means of which it may be kept constantly full of air. This M. Kempelen considers a very essential, or even an indispensible part of the ma chine. Besides these there are„small additional bellows, for the purpose of aiding the production of such sounds as I', K, T, which need a greater emission of air.
The nose consists of two tin tubes communicating with the mouth. When the mouth-piece is closed, and both tubes remain open, a perfect M is heard ; when one is closed, but the other is open, N is sounded.
It is necessary to add to this brief account of the principal parts of M. Kempelen's speaking machine, that the sound was regulated in a great measure by various modifications and compressions of the mouth. Four letters, D, G, K, T, he never could obtain perfeotly, and substituted a P in expressing them, which was so managed as to bear a considerable re semblance, according to the mode ()fusing it, and suffi cient to deceive the auditor. NeVertheless M. Kempe len could produce not only words, but entire senten ces,: such as opera, astronomy, Constantinopolis; or icous cues mon ami—je vous aznze de tout mon cceur Leopoldus secundus—Romanorron inzperator seniper Augustus, and the like. We acknowledge ourselves ignorant of the precise figure under which this ma chine, no less remark-ible for ingenuity than simpli city, was ultimately adopted. At first it was ex hibited only with the union of its essential parts ; Kempelen next proposed that it should be an automaton like a child; and although we have rea son to believe that his, intention was fulfilled, our certainty has induced us to place our account of it At here rather than under ANDROIDE'.
The more complicated automata are greatly prized in the East ; and some years ago constituted a kind of traffic from Great Britain. China, we have under stood, was the place where the greatest prices were given for them : and we know also, that some automata of ingenious workmanship were carried from this country with the last embassy, as the most acceptable present that could be offered to the Chinese emperor. (c)