Modern Magic: A Practical Treatise on the Art of Conjuring

Both the apertures were guarded by leather, to prevent unnecessary waste of air: two smaller air-chests were then put into it, each having a valve above closed by the pressure 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 was placed in the large air-chest, so as to be between the smaller air-chests. When all these parts were fitted to the air-chest, the operation of one lever raising the valve of the first smaller chest connected with the tin funnel produced the sound s; while the operation of another, raising the valve of the second smaller chest connected with the wooden tube, produced the sound of sch. But it is proper further to explain that instead of being a simple tunnel, it was, in fact, a tin box, with a square hole in the outer end, nearly covered by a slip of pasteboard; and the wooden tube was merely the mouth-piece of a common flute, closed at the lower extremity, and with the air-hole modified and contracted: the letter r was produced by the rapid vibration of the ivory slip, owing to a strong discharge of air.