les with any sensible Effect.

All Bodies seem to be composed of hard Particles: For otherwise Fluids
would not congeal; as Water, Oils, Vinegar, and Spirit or Oil of Vitriol
do by freezing; Mercury by Fumes of Lead; Spirit of Nitre and Mercury,
by dissolving the Mercury and evaporating the Flegm; Spirit of Wine and
Spirit of Urine, by deflegming and mixing them; and Spirit of Urine and
Spirit of Salt, by subliming them together to make Sal-armoniac. Even
the Rays of Light seem to be hard Bodies; for otherwise they would not
retain different Properties in their different Sides. And therefore
Hardness may be reckon'd the Property of all uncompounded Matter. At
least, this seems to be as evident as the universal Impenetrability of
Matter. For all Bodies, so far as Experience reaches, are either hard,
or may be harden'd; and we have no other Evidence of universal
Impenetrability, besides a large Experience without an experimental
Exception. Now if compound Bodies are so very hard as we find some of
them to be, and yet are very porous, and consist of Parts which are only
laid together; the simple Particles which are void of Pores, and were
never yet divided, must be much harder. For such hard Particles being
heaped up together, can scarce touch one another in more than a few
Points, and therefore must be separable by much less Force than is
requisite to break a solid Particle, whose Parts touch in all the Space
between them, without any Pores or Interstices to weaken their Cohesion.
And how such very hard Particles which are only laid together and touch
only in a few Points, can stick together, and that so firmly as they do,
without the assistance of something which causes them to be attracted or
press'd towards one another, is very difficult to conceive.

The same thing I infer also from the cohering of two polish'd Marbles
_in vacuo_, and from the standing of Quick-silver in the Barometer at
the height of 50, 60 or 70 Inches, or above, when ever it is well-purged
of Air and carefully poured in, so that its Parts be every where
contiguous both to one another and to the Glass. The Atmosphere by its
weight presses the Quick-silver into the Glass, to the height of 29 or
30 Inches. And some other Agent raises it higher, not by pressing it
into the Glass, but by making its Parts stick to the Glass, and to one
another. For upon any discontinuation of Parts, made either by Bubbles
or by shaking the Glass, the whole Mercury falls