This pipe goes by H V, and joins the upright pipe _u_ I, to
make a jet, as 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.

[Illustration: Fig. 7.]

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.

_Inflammable Phosphorus._

Take the meal of flour of any vegetable, put it into an iron pan over
a moderate fire, and keep it stirring with an iron spoon till it
changes to a black powder; to one part of this add four parts of raw
alum. Make the whole into a fine powder; put it again into the iron
pan, and keep stirring it till it almost catches fire, to prevent its
forming into lumps, as it is apt to do when the alum melts; in which
case it must be broken again, stirred about, and accurately mixed with
the flour, till it emits no more fumes, and the whole appears a fine
black powder.

Put this powder in a clean dry phial with a narrow neck, filling it to
about one-third of the top. Then stop the mouth of the phial with
loose paper, so as to let the air pass freely through it, and leave
room for the fumes to come through the neck. Place the phial in a
crucible, encompassed on all sides with sand, so that it may not touch
any part of the crucible, but a considerable space everywhere left
between. The phial must be covered up with sand, leaving only a small
part bare, by which you can discern whether the powder is ignited. In
this state, the crucible is to be surrounded with coals, kindled
slowly till it is well heated on all sides, and then the fire is to be
raised, till the crucible and every thing in it is red-hot; keep it in
this state an hour; after this, the fire still burning as fiercely,
close up the orifice of the phial with wax, to exclude the air. Leave
it to cool, and you will find in it a black dusty coal formed of the
flour and alum.

Shake a