What I call the sides AA are about four inches deep, acd seem to supply the office of the sides of a drum, while the flat part BB answers to the stretched parchment ; only there is a round part in the middle to stiffen it. On this raised part you beat with a ball of packthread of four or five inches diameter, fastened to the end of a stick. The metal, at a mean, is about one-eighth of an inch thick, bu' unequal, the whole form being manifestly raised out of., flat plate by the hammer. The tone is amazingly de p, clear, and sonorous. The note of that I saw, and had syme time in my possession, was F, an octave below the F fi ut cliff in the bass." See our article GONG.
That music which is produced by clocks with or:an barrels must be greatly preferable to that of bells, rnd the apparatus for marking the tunes on clock barrels is equally suited to do the same on barrels intended by machinery to work or to sound the pipes of an organ; the difference consisting in marking off on the barrel the spaces of the longer and shorter notes, as in place of phis they have staples or bridges of various lengths, according to the length of the note, or the time which the pipe should be allowed to sound it: The very short notes at e by pins of different thicknesses. When an organ part is put to a clock, considerable power or force of weight or spring is required ; small as the organ may be, or its wind c hest, some force is required to work the bellows, so as to keep the wind-chest full, and no more. To work the bellows, that is, to move the lower board of than up and down, on the inside of which is an air valve that opens on the board being moved downwards, and on the motion upwards it shuts, and the air being then compressed, it is Forced into the wind-chest by a communication between them for that purpose, and is ready to give sound to any of the organ pipes the moment when any of their valves should open. This operation with the bellows, though of a different shape, is just the same as with the common bellows when Nerving up a fire. The bellows is worked by means of a short crank fixed on one end of the arbor of an endless screw, which works into a trundle of a high numbered pi nion, which is on the end of the organ barrel, and nearly of the same diameter with it. On the other end of the end less screw arbor is fixed a small jagged pulley, over which is put an endless silken cord, which being continued, goes round another jagged pulley on the end of a pinion arbor of one of the quick running or fly wheels in the organ train. These wheels are regulated by a fly, by which the velocity of the organ barrel in turning is brought to keep the time required for the music. The wheels, on being impelled by the moving power, which is considerable, (be ing greater than that used in bell music,) communicates their motion by means of the endless cot d, and turns the organ barrel. The pins, bridges, or staples, on the barrel turning, act on the tails of levers nearly similar in form to the hammer tails of the bell musical clock, only they are a little longer, and equally moveable on a centre or wire. The other arms of these levers are in an opposite direc tion, and are about the same length as those which are lift ed by the staples on the barrel when turning, and are a lit tle bloat] and flattish towards the end, where the under side (on the opposite ends rising) press down on the upper ends of the slender rods, whose lower ends then by this means open the valves of the organ pipes, and the sound is pro longed according as the lift is pins or bridges. What has
been described constitutes the chief machinery in an organ clock. Many ways may be contrived to set the organ bar rel in motion, and at the same time while playing, and at the end of a tune, to make the clock of itself shift the bar rel from one tune to another.
Within these two or three years, a new species of Music by steel springs has been invented at Geneva. From the smallness of the machinery which plays the music, it is very surprising and curious, as it has been put into ngs, seals, watches, and snuff boxes. Two ways are used tc lift the ends of the springs which give the different s ; one is by a very small barrel, the other by a plate wh el. The last, being more adapted to take up little roof, is chiefly used in watches. The space for the spr'ogs falling, after being bent up, is short. A double set of springs for giving the same notes is made, with out which the beauty of the music could not be produced. Th3 number of springs varies, for the most part, from six.een to twenty-four, or upwards. Those springs which are .ifted by the barrel pins are straight, while those which are lifted by the pins in the plate wheel have a scut of part projecting from the end at one side ; and this side edge of the spring lying over the top of the pins is taken away, so as to clear them. The projecting part at the end of each spring corresponds tvitb its own lilting pin. As the pins are on both sides of the plate-wheel, this allows a greater variety of notes than the bat Fel can perhaps admit. The springs on the upper and tinder sides of the plate-wheel are sometimes sixteen or seventeen on each side. On the plate-wheel are traced 16 or 17 concentric circles, for the pins to meet their corresponding Dotes in the springs, whose ends came each to their corresponding circle both above and under the plate-wheel. An apparatus on a small scale being made like that which has been describer), will serve to put or mark the places for the !lows both en the barrel and the plate-wheel ; the only ditnrence is, that the barrel will require to be marked by a curved arm sliding on a steel rod. The concentric circles on the plate wheel must have short and faint traces across them : This is regulat ed by athin straight edge, laid in an oblique direction across the circles, and the intersections are afterwards marked by a point. The springs may be easily tuned to their respec tive notes, as the least thinning or shortening them will make a very sensible alteration on the tone. The tongue of a steel trump, or Jew's harp, spews, in some degree, what may be done in this way by steel springs. The train which regulates this very minute musical machinery, as may very easily be conceived, must he composed of a few very small wheels, the motive force being proportionably small. It must be a great effol t of patience and ingenuity to make them play two or mot e tunes. However beautiful and ingenious the machinery of these small contrivances is, they can only be considered as toys for amusing children.
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