Section 77
No. 77. An Altar Organ blown by the agency of a Wind-mill.
THE construction of an organ from which, when the wind blows, the sound
of a flute shall be produced. Let A, A, A, (fig. 77), be the pipes, B C
the transverse tube communicating with them, D E the vertical tube, and
E F another transverse tube leading from D E into a box G H, the inner
surface of which is made level to fit a piston. Into this box fit the
piston K L, which is capable of descending into it freely. To the piston
attach a rod, M N, and to this another, N X, working on the rod P R. At
N let there be a pin moving readily, and to the extremity X fasten a
small plate, X 0, near which a rod, S, is to be placed, moving on iron
pivots placed in a frame which admits of being shifted. To the rod S
attach two small wheels, U and Q, of which U is furnished with pegs
placed close to the plate X 0, and Q with broad arms like the sails of a
wind-mill. When all of these arms, urged by the wind, drive round the
wheel Q, the rod S will be driven round, so that the wheel U and the
pegs attached to it will strike the plate X O at
intervals and raise the piston; when the peg recedes, the piston,
descending, will force out the air in the box G H into the tubes and
pipes, and produce the sound. We may always move the frame which
contains the rod S towards the prevailing wind, that the revolution may
be more rapid and uniform.
Section 78.
Index.