Against the wall of a room, near the ceiling, fix a wheel of twelve or
eighteen inches diameter; on the rim of which place a number of bells
in tune, and, if you please, of different sizes. To the axis of this
wheel there should be fixed a fly to regulate its motion; and round
the circumference there must be wound a rope, to the end of which is
hung a weight.

Near to the wheel let a stand be fixed, on which is an upright piece
that holds a balance or moveable lever, on one end of which rests the
weight just mentioned; and to the other end must hang an inverted
hollow cone, or funnel, the aperture of which is very small. This cone
must be graduated on the inside, that the sand put in may answer to
the number of hours it is to run. Against the upright piece, on the
side next the cone, there must be fixed a check, to prevent it from
descending. This stand, together with the wheel, may be enclosed in a
case, and so contrived, as to be moved from one room to another with
very little trouble.

It is evident, from the construction of this machine, that when a
certain quantity of the sand is run out, the weight will descend, and
put the wheel in motion, which motion will continue till the weight
comes to the ground. If the wheel be required to continue longer in
motion, two or more pulleys may be added, over which the rope may run.

_Musical Cascade._

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 casc