of gold must have
contained molecules of gold composed of atoms. What must have been the
size of the atoms therefore of which the sheet was composed?

ART. 33. _The Atomic Theory._--The Atomic Theory was revived by Dalton
in 1804, in order to account for the fact that elements unite in certain
definite proportions. From that time to the present, the theory has
grown and developed until at the present time it is looked upon as a
well-established theory. It is, however, simply a theory, and from the
very nature of the hypothesis is incapable of proof. No one has ever
seen an atom of hydrogen or oxygen, or an atom of any solid, liquid, or
gaseous matter. The Atomic Theory suggests, therefore, that there is a
limit to the divisibility of matter. All chemical experiments lend
support to the theory, and by it we are able to give an intelligible and
easy method of expression to what would otherwise be difficult phenomena
to explain.

Ancient philosophers were divided on the question of the infinite
divisibility of matter. The Epicureans were of the opinion that matter
was incapable of infinite division, and that even if we were able to
make the smallest possible division, it would be impossible for us to
reach the smallest particle termed "Atom."

ART. 34. _Kinds of Atoms._--Various forms of atoms have been conceived
by philosophers from time to time, ranging from the Hard Atom, and the
simple point-centres of Boscovitch, until we come to the more modern
Vortex Atom of Lord Kelvin, or the Strain Atom of Dr. Larmor, which will
be looked at separately. Democritus conceived a hard atom as long ago as
500 B.C., while the notion of a hard atom is not absent from the works
of Newton himself. We find that Newton suggested that the particles of
air might be hard spherical bodies, at a distance from one another of
about nine times their diameter.

The hard atom, however, seems to be refuted by spectroscopic analysis,
which reveals to us in a manner that has never been revealed before,
something of the sizes and vibrations of atoms.

From the phenomenon of heat, which is simply matter in motion, we feel
compelled to accept the fact that an atom is not a hard particle, but
that it is something which is more closely allied to the Vortex Atom, or
the Strain Atom of Dr. Larmor.

_Boscovitch Atom._--According to Boscovitch's theory, each atom is
simply an indivisible point in space capable of motion, and possessing a
certain mass