easily relinquish one another; and this, though the bodies be _aliquatenus_
fluid, and in motion by one another, which, to such as consider a fluid
body only as its parts are in a confused irregular motion, without taking
in also the congruity of the parts one among another, and incongruity to
some other bodies, does appear not a little strange. So that besides the
incongruity of the ambient fluid to it, we are to consider also the
congruity of the parts of the contein'd fluid one with another.

And this Congruity (that I may here a little further explain it) is both a
Tenaceous and an Attractive power; for the Congruity, in the Vibrative
motions, may be the cause of all kind of attraction, not only Electrical,
but Magnetical also, and therefore it may be also of Tenacity and
Glutinousness. For, from a perfect congruity of the motions of two distant
bodies, the intermediate fluid particles are separated and droven away from
between them, and thereby those congruous bodies are, by the incompassing
mediums, compell'd and forced neerer together; wherefore that
attractiveness must needs be stronger, when, by an immediate contact, they
are forc'd to be exactly the same: As I shew more at large in my _Theory_
of the _Magnet_. And this hints to me the reason of the suspension of the
_Mercury_ many inches, nay many feet, above the usual station of 30 inches.
For the parts of _Quick-Silver,_ being so very similar and congruous to
each other, if once united, will not easily suffer a divulsion: And the
parts of water, that were any wayes _heterogeneous_, being by _exantlation_
or rarefaction exhausted, the remaining parts being also very similar, will
not easily part neither. And the parts of the Glass being solid, are more
difficultly disjoyn'd; and the water, being somewhat similar to both, is,
as it were, a medium to unite both the _Glass_ and the _Mercury_ together.
So that all three being united, and not very dissimilar, by means of this
contact, if care be taken that the Tube in erecting be not shogged, the
_Quicksilver_ will remain suspended, notwithstanding its contrary indeavour