— 125 —
From Hardness.       §4. Solidity is hereby also differenced from Hardness, in that Solidity
consists in repletion, and so an utter Exclusion of other Bodies out
of the space it possesses; but Hardness, in a firm Cohesion of the
parts of Matter, making up masses of a sensible bulk, so that the
whole does not easily change its Figure. And indeed, Hard and Soft
are Names that we give to things, only in relation to the Consti-
tutions of our own Bodies; that being generally call’d hard by us,
which will put us to Pain, sooner than change Figure by the pressure
of any part of our Bodies; and that, on the contrary, soft, which
changes the Situation of its parts upon an easie, and unpainful
touch.
But this Difficulty of changing the Situation of the sensible parts
amongst themselves, or of the Figure of the whole, gives no more
Solidity to the hardest Body in the World, than to the softest; nor is
an Adamant one jot more solid than Water. For though the two
flat sides of two pieces of Marble, will more easily approach each
other, between which there is nothing but Water or Air, than if
there be a Diamond hetween them: yet it is not, that the parts of
the Diamond are more solid than those of Water, or resist more; but
because the parts of Water, being more easily separable from each
other, they will by a side-motion be more easily removed, and give
way to the approach of the two pieces of Marble: But if they could
be kept from making Place, by that side-motion, they would eter-
nally hinder the approach of these two pieces of Marble, as much as
the Diamond; and ’twould be as impossible by any force, to sur-
mount their Resistance, as to surmount the Resistance of the parts
of a Diamond. The softest Body in the World will as invincibly
resist the coming together of any two other Bodies, if it be not put
out of the way, but remain between them, as the hardest, that can
be found, or imagined. He that shall fill a yielding soft Body well
with Air or Water, will quickly find its Resistance: And he that
thinks, that nothing but Bodies, that are hard, can keep his Hands
from approaching one another, may be pleased to make a trial, with
the Air inclosed in a Football. The Experiment, I have been told
was made at Florence, with a hollow Globe of Gold fill’d with
— 126 —
Water, and exactly closed, farther shews the solidity of so soft a
body as Water. For the golden Globe thus filled, being put into a
Press, which was driven by the extreme force of skrews, the water
made it self way through the pores of that very close metal, and
finding no room for a nearer approach of its Particles within, got to
the outside, where it rose like a dew, and so fell in drops, before
the sides of the Globe could be made to yield to the violent com-
pression of the Engine, that squeezed it.
Locke Hum II, 4, §4, pp. 125-126