such an one as is described in the _Sixth Figure_. For if into it you put
Water enough to fill it as high as _AB_, and gently blow in at _D_, you
shall _depress_ the Superficies _B_, and thereby _raise_ the opposite
Superficies _A_ to a _considerable height_, and by gently _sucking_ you may
produce clean _contrary_ effects.

Next, That there is such an _unequal pressure_, I shall prove from this,
_That there is a much greater incongruity of Air to Glass, and some other
Bodies, then there is of Water to the same_.

By _Congruity, I mean a property of a fluid Body, whereby any part of it is
readily united with any other part, either of itself, or of any other
Similar, fluid, or solid body: And by Incongruity a property of a fluid, by
which it is hindred from uniting with any dissimilar, fluid, or solid
Body._

This last property, any one that hath been observingly conversant about
fluid Bodies, cannot be ignorant of. For (not now to mention several
_Chymical Spirits_ and _Oyls_, which will _very hardly_, if at _all_, be
brought to _mix_ with one another; insomuch that there may be found some 8
or 9, or more, several distinct Liquors, which _swimming_ one upon another,
will not presently _mix_) we need seek no further for Examples of this kind
in _fluids_, then to observe the _drops of rain_ falling through the _air_
and the _bubbles of air_ which are by any means conveyed under the surface
of the _water_; or a drop of common _Sallet Oyl_ swimming upon water. In
all which, and many more examples of this kind that might be enumerated,
the _incongruity_ of two _fluids_ is easily discernable. And as for the
_Congruity_ or _Incongruity_ of Liquids, with several kinds of _firm_
Bodies, they have long since been taken notice of, and called by the Names
of _Driness_ and _Moisture_ (though these two names are not comprehensive