f _Air_, and then
gently pouring in water into the Pipe AB, he must observe diligently how
high the water will rise in it before it protrude the _bubble_ of Air C,
through the narrow passage of F, and denote exactly the height of the
_Cylinder_ of water, then cementing in a second Pipe as G, and filling it
with water; he may proceed as with the former, denoting likewise the height
of the _Cylinder_ of water, able to protrude the _bubble_ C through the
passage of G, the like may he do with the next _Pipe_, and the next, &c. as
far as he is able: then comparing the several heights of the _Cylinders_,
with the several _holes_ through which each _Cylinder_ did force the _air_
(having due regard to the _Cylinders_ of water in the small _Tubes_) it
will be very easie to determine, what force is requisite to press the _Air_
into such and such _a hole_, or (to apply it to our present experiment) how
much of the pressure of the _Air_ is taken off by its ingress into smaller
and smaller _holes_. From the application of which to the entring of the
_Air_ into the bigger _hole_ of the _Vessel_, and into the smaller _hole_
of the _Pipe_, we shall clearly find, that there is a greater pressure of
the air upon the water in the _Vessel_ or greater _pipe_, then there is
upon that in the lesser _pipe_: For since the pressure of the _air_ every
way is found to be equal, that is, as much as is able to press up and
sustain a _Cylinder_ of _Quicksilver_ of two foot and a half high, or
thereabouts; And since of this pressure so many more degrees are required
to force the _Air_ into a smaller then into a greater _hole_ that is full
of a more congruous fluid. And lastly, since those degrees that are
requisite to press it in, are thereby taken off from the _Air_ within, and
the _Air_ within left with so many degrees of pressure less then the _Air_
without; it will follow, that the _Air_ in the less _Tube_ or _pipe_, will
have less pressure against the superficies of the _water_ therein, then the
_Air_ in the bigger: which was the minor Proposition to be proved.

The Conclusion therefore will necessarily follow, _viz._ That _this unequal
pressure of the Air caused by its ingress into unequal holes, is a cause
sufficient to produce this effect, without the help of any other
concurrent_; therefore is probably the principal (if not the only) cause of
these _Phaenomena_.

This therefore being thus explained, there will be divers _Phaenomena_
explicabl