the
masses of matter, have obtained no specific names, nor have been
sufficiently considered; though they appear to be as powerful agents
as the attractions.

The motions of ethereal fluids, as of magnetism and electricity, are
yet imperfectly understood, and seem to depend both on chemical
affinity, and on gravitation; and also on the peculiar repulsions of
the particles of bodies, and on the general repulsion of the masses of
matter.

In what manner attraction and repulsion are produced has not yet been
attempted to be explained by modern philosophers; but as nothing can
act, where it does not exist, all distant attraction of the particles
of bodies, as well as general gravitation, must be ascribed to some
still finer ethereal fluid; which fills up all space between the suns
and their planets, as well as the interstices of coherent matter.
Repulsion in the same manner must consist of some finer ethereal
fluid; which at first projected the planets from the sun, and I
suppose prevents their return to it; and which occasionally
volatilizes or decomposes solid bodies into fluid or aerial ones, and
perhaps into ethereal ones.

May not the ethereal matter which constitutes repulsion, be the same
as the matter of heat in its diffused state; which in its quiescent
state is combined with various bodies, as appears from many chemical
explosions, in which so much heat is set at liberty? The ethereal
matter, which constitutes attraction, we are less acquainted with; but
it may also exist combined with bodies, as well as in its diffused
state; since the specific gravities of some metallic mixtures are said
not to accord with what ought to result from the combination of their
specific gravities, which existed before their mixture; but their
absolute gravities have not been attended to sufficiently; as these
have always been supposed to depend on their quantity of matter, and
situation in respect to the centre of the earth.

The ethereal fluids, which constitute peculiar repulsions and
attractions, appear to gravitate round the particles of bodies mixed
together; as those, which constitute the general repulsion or
attraction, appear to gravitate round the greater masses of matter
mixed together; but that which constitutes attraction seems to exist
in a denser state next to the particles or masses of matter; and that
which constitutes repulsion to exist more powerfully in a sphere
further from them; whence many bodies attract