Section 68
No. 68. A Shrine over which a Bird may be made to revolve and sing by
Worshippcrs turning a wheel.
THE construction of a shrine provided
with a revolving wheel of bronze, termed a purifier,
which worshippers are accustomed to
turn round as they enter. Let it be required that,
if the wheel is turned, the note of the black-cap
shall be produced, and the bird,
standing on the top of the shrine, turn round as well; while, if
the wheel is
turned [in the opposite direction], the black-cap neither sings nor
revolves. Let A B C D (fig. 68), be the shrine and E F an axis
extending across it, capable of revolving freely, to which the
wheel H K, which is to be turned round, is attached. Let two
other wheels be attached to the axis,
in the interior of the shrine, L and M, of which L has
a
pulley, and M is a wheel with rays. Round the pulley a cord is wound,
from the extremity of which is suspended a
vessel N, shaped like a conical oven, and provided with a tube X 0,
terminating in a small pipe which produces the note of a black-cap:
under the conical vessel N must be placed a vessel of water. From the
top of the shrine let fall a small axis S T capable of revolving freely:
at the extremity S let a black-cap be placed, and at T a wheel with
rays, the rays of which are implicated with, or take into, the rays of
the wheel M. It will be found that, when the wheel H K is made to
revolve, the cord is wound round the pulley and raises the conical vessel
N; but, if the wheel is let go, N descends by its own weight into the
water and produces the sound by the expulsion of the air. The black-cap
turns round at the same time owing to the revolution of the wheels.
Section 69.
Index.