thousand years to complete the task!
Consequently, although the increase of the diameter
of a revolving atom's orbit by the communication
of heat, is insensible, the sum of an
almost infinite number of increased orbits
becomes perfectly sensible.

Comparing the infinitely small with the
infinitely great, it is held that a body, of what
kind soever, represents in miniature, and very
exactly, an astronomical system, like those
which, weather permitting, we behold every
night in the firmament.

Astronomers are perfectly aware that the
earth is only a molecule amidst the innumerable
stars which constitute the Milky Way.  But a
body, never mind what—take wood, gold, or
diamond, to have a clear idea—is nothing more
than a heap of molecular constellations diversely
grouped.  From the extreme of vastness to the
extreme of minuteness, the analysis holds good
throughout.  Although our eye is not framed
to perceive in all their details these infinitely
small stars and systems of stars, other creatures,
as for example insects, whose vision is differently
constituted to ours, may possibly—although not
probably—be able to see some of them.

One thing, however, appears certain; if we
could construct a microscope of sufficient power,
we should be able, by the help of such an
instrument, to resolve the molecular constellations
of every little terrestrial milky way, exactly as
our first-rate telescopes resolve the celestial
nebulae and separate double and triple stars. It
is a mere question of visual power.  Were our
sight sufficiently penetrating, we should
behold what now appear mere confused heaps
of matter, arranged in groups of admirable
symmetry.  Bodies would appear honeycombed in
all directions.  Daylight would stream through
vast interstices, as it does between the columns
of a temple or the tree-trunks of a forest.  Nay,
we should see immense empty spaces, like those
which intervene between the planets.

From distance to distance, too, we should
perceive clusters of stars in harmonious order,
each surrounded by its own proper atmosphere;
and—still more astounding spectacle!—every
one of those little molecular stars would be
found revolving with giddy rapidity in more or
less elongated ovals, exactly like the great stars
of heaven; while by increasing the power of
our instrument, we should discover around each
principal star, minor stars—satellites resembling
our moon—accomplishing their revolutions
swiftly and regularly.  This view of the
constitution of matter is aptly described by M. de
Parville as molecular astronomy, maintaining
even that astronomy, without our suspecting it,
is dependent on mineralogy; and that whenever
we shall have discovered the laws which govern
the groupings and the movements of the
infinitely small, astronomers will have only to
follow in our track.  But who, a hundred years
ago, could dare to imagine that the infinitely
small was so infinitely great?  What is now believed
to be the nearest guess at the truth, appears,
at first sight, to be the dream of a madman.

Those who love to indulge in paradox now
state that their theory is very simple. For
them, the solar system is a solid particle,
homogeneous. The planets composing it are
molecules which virtually crowd each other, touch,
and adhere.  The space between them is no
more than the interval which separates the
atoms of the compactest metal—silver, iron, or
platina!  Distance, therefore, it is argued, is an,
empty word; distance, in fact, does not exist.
Nevertheless, a man may convince himself that
distance, for him, is not an empty word, by
jumping out of a first-floor window.

The wonder is that these molecular motions,
so rapid as to escape human observation, are yet
able to impress human senses, to give us pain
or pleasure, to help us to live, or to cause us to
die.  And unseizable as atoms are, they can,
nevertheless, be counted and weighed.  Chemists
have determined the relative weights of the
atoms of different substances.  Calling the
weight of a hydrogen atom, one, the weight of
an oxygen atom is sixteen.  Hence, to make up
a pound-weight of hydrogen, sixteen times the
number of atoms contained in a pound of oxygen
would be necessary.

What a strange result of the study of atoms!
Heat and light, whose origin was inscrutable
or attributed to some mysterious hypothetical
fluid, are now traced to their causes.
The reader has already been informed that the
heat of the sun is attributed to the collision
he sustains from a never-ceasing shower of
meteors.*  The heat of terrestrial fire is
similarly produced.  All cases of combustion,
Tyndall tells us, are to be ascribed to the
collision of atoms which have been urged together
by their mutual attractions.  It is to the
clashing together of the oxygen of the air and
the constituents of our gas and candles, that
the light and heat of our flames are due.  It is
the impact of the atoms of oxygen against the
atoms of sulphur, which produces the heat and
flame observed when sulphur is burned in
oxygen or in air. To the collision of the same
atoms against phosphorus, are due the intense
heat and dazzling fight which result from the
combustion of phosphorus in oxygen gas.
Whether atoms are concerned, or suns and
planets, the theory is equally applicable and true,
*  See volume xiii., p. 537.

When interatomic movements occur under
given conditions of mass and velocity, they
make an impression on the eye.  Their
undulations, communicated from one to the other,
strike the retina, and in turn set vibrating the
atoms of which it is composed.  We see; we
receive the impression of light.  And accordingly
as the vibrations occur with certain proportional
rapidities, they give us the sense of
blue, yellow, red, and the other visible tints of
the rainbow—because there are certainly other
tints which are not visible to the human eye,
exactly as there are sounds not audible to the
human ear.  Atoms and their motions are
therefore the physical cause of colour.
Wonderful as it must appear, the length of the
waves both of sound and light, and the number