of Gravity, a great height above its ordinary Station; but if this
immediate Contact be removed, either by a meer separation of them one from
another by the force of a shog, whereby the other becomes imbodied between
them, and licks up from the surface some agil parts, and so hurling them
makes them air, or else by some small heterogeneous agil part of the Water,
or Air, or Quicksilver, which appears like a bubble, and by its jumbling to
and fro there is made way for the _heterogeneous Æther_ to obtrude it self
between the Glass and either of the other Fluids, the Gravity of _Mercury
precipitates_ it downward with very great violence; and if the Vessel that
holds the restagnating _Mercury_ be convenient, the _Mercury_ will for a
time _vibrate_ to and fro with very large _reciprocations_, and at last
will remain kept up by the pressure of the external Air at the height of
neer thirty inches. And whereas it may be objected, that it cannot be, that
the meer imbodying of the _Æther_ between these bodies can be the cause,
since the _Æther_ having a free passage alwayes, both through the Pores of
the Glass, and through those of the Fluids, there is no reason why it
should not make a separation at all times whilst it remains suspended, as
when it is violently dis-joyned by a shog. To this I answer, That though
the _Æther_ passes between the Particles, that is, through the Pores of
bodies, so as that any chasme or separation being made, it has infinite
passages to admit its entry into it, yet such is the tenacity or attractive
virtue of Congruity, that till it be overcome by the meer strength of
Gravity, or by a shog assisting that Conatus of Gravity, or by an agil
Particle, that is like a leaver agitated by the _Æther_; and thereby the
parts of the congruous substances are separated so far asunder, that the
strength of congruity is so far weakened, as not to be able to reunite
them, the parts to be taken hold of being removed out of the attractive
Sphere, as I may so speak, of the congruity; such, I say, is the tenacity
of congruity, that it retains and holds the almost contiguous Particles of
the Fluid, and suffers them not to be separated, till by meer force that