The Illuminated Fountain That Plays When The Candles Are Lighted
and stops when they are extinguished.
Provide two cylindrical vessels, A B and C D, as in Fig. 6. Connect
them by four tubes open at each end, as H I, &c., so that the air may
descend out of the higher into the lower vessel. To these tubes fix
candlesticks, and to the hollow cover, E F, of the lower vessel, fit a
tube, K, reaching almost to the bottom of the vessel. At G let there
be an aperture with a screw, whereby water may be poured into C D,
which, when filled, must be closed by the screw.
When the candles are lighted, the air in the upper cover and
contiguous pipes will be thereby rarefied, and the jet from the small
tube, K, will begin to play: as the air becomes more rarefied, the
force of the jet will increase, and it will continue to play till the
water in the lower vessel is exhausted. As the motion of the jet is
caused by the heat of the candles, when they are extinguished the
fountain will stop.