A Fountain Which Acts By The Heat Of The Sun
In the annexed engraving, Fig. 7, G N S is a thin hollow globe of
copper, eighteen inches diameter, supported by a small inverted basin,
placed on a stand with four legs, A B C D, which have between them, at
the bottom, a basin of two feet diameter. Through the leg C passes a
concealed pipe, which comes from G, the bottom of the inside of the
globe. This pipe goes by H V, and joins the upright pipe u I, to
make a jet,
s I. The short pipe, u I, which goes to the bottom, has
a valve at u, under the horizontal pipe H V, and another valve at T,
above that Horizontal pipe, under the cock at K. The use of this cock
is to keep the fountain from playing in the day, if you think proper.
The north pole N of the globe has a screw that opens a hole, whereby
water is poured into the globe.
The machine being thus prepared, and the globe half filled with water,
put it in an open place, when the heat of the sun rarefying the air as
it heats the copper, the air will press strongly against the water,
which, coming down the pipe, will lift up the valve at V, and shut the
valve at u. The cock being opened, the water will spout out at I, and
continue to play a long while, if the sun shines.