d, liquid, or aeriform?

When the principle of _attraction_ prevails, it causes them to become
solid; when caloric prevails, they become aeriform. Fluidity is,
apparently, a medium between the two.

How is the state of Solidity in bodies accounted for?

The particles of all bodies are subject to two opposite powers,
_repulsion_ and _attraction_; between which they remain in
equilibrium. While the _attractive_ force remains strongest, the body
remains in a state of solidity; but if heat destroys this force, the
particles lose their cohesion, and the body ceases to be solid.

_Cohesion_, act of sticking together, union of the
constituent parts of a body.

Which is supposed to be the most natural state of all bodies?

Solidity; for by the _combination_ of caloric with them we can reduce
most substances to the fluid state; while the greatest number of
_liquid_ substances take a _solid_ form by the loss of caloric. Thus,
water congeals and forms ice; and even the gases show this disposition
to become solid, when they lose their _elasticity_ by forming some
_combination_.

Explain the terms _Repulsion_ and _Attraction_.

Repulsion is a peculiar property in the particles of matter, which
gives them a constant tendency to recede from each other. Attraction
is an unknown force, which causes bodies or their particles to
approach each other. The particles of all bodies possess this
property, which causes them to adhere, and preserves the various
substances around us from falling in pieces.

What different kinds of Attraction can you mention?

Attraction may be distinguished into that which takes place between
bodies at sensible distances, and that which manifests itself between
the _particles_ of matter at insensible distances.

Give an example of the first kind of attraction.

One of the most familiar instances of attraction at sensible distances
is seen in the descent of heavy bodies to the ground. When a stone is
lifted up in the hand, the earth's attraction, which previously caused
it to remain at its surface, is overcome; but, as soon as the hand is
withdrawn, the stone falls to the earth. The force which causes this
is called the _attraction of gravitation_, or simply _gravitation_.

How is the second kind of attraction, or that between the particles of
bodies, subdivided?

Into the _attraction of aggregation_, or _cohesion_; and _chemical
attraction_, or _affinity_. The former takes pl