Where there is a natural cascade, near the lower stream, but not in it, let there be placed a large wheel, equal to the breadth of the cascade: the diameter of this wheel, for about a foot from each end, must be much less than that of the middle part; and all the water from the cascade must be made to fall on the ends. The water that falls on the wheel may pass through pipes, so that part of it may be made occasionally to pass over or fall short of the wheel, as you would have the time of the music quicker or slower. The remaining part of the wheel, which is to be kept free from the water, must consist of bars, on which are placed stops that strike against the bells: these stops must likewise be moveable. It is evident from the construction of this machine, that the water falling on the floats at the end of the wheel, will make the stops, which are adapted to different tunes, strike the notes of those tunes on the respective bells. Two or three sets of bells may here be placed on the same line, when the cascade is sufficiently wide. Where there is not a natural cascade, one may be artificially constructed, by raising part of the ground, wherever there is a descent of water; whether it be a stream that supplies a reservoir or fountain, or serves domestic uses; or if it be refuse water that has already served some other purpose. _Writing on Glass by the Rays of the Sun._ Dissolve chalk in aqua fortis, to the consistence of milk, and add to that a strong solution of silver. Keep this liquor in a glass decanter well stopped. Then cut out from a paper the letters you would have appear, and paste the paper on the decanter, which you are to place in the sun, in such a manner that its rays may pass through the spaces cut out of the paper, and fall on the surface of the liquor. The part of the glass through which the rays pass will turn black, and that under the paper will remain white. You must observe not to move the bottle during the time of the operation. _To produce the Appearance of a Flower from its Ashes._ Make a tin box, with a cover that takes off. Let this box be supported by a pedestal of the same metal, and on which there is a little door. In the front of this box is to be a glass. In a groove, at a small distance from this glass, place a double glass, made in the same manner as described in p. 13, (_Magic Picture._) Between the front and back glasses place a small upright tin tube, supported by a cross piece. Let there be also a small chafing-dish placed in the pedestal. The box is to be opened behind. You privately place a flower in the tin tube, but not so near the front glass as to be in the least degree visible, and presenting one that resembles it to any person, desire him to burn it on the coals in a chafing-dish.