earth, allowing the heavenly bodies to make
their daily peregrinations. The earth's extent
once admitted to be limited, the idea of its
roundness would soon come to explain it;
and, little by little, the earth came to be
acknowledged as a globe suspended in space, and
resting on nothing.

After this first grand step, it was remarked
that the other heavenly bodies are also globes
whose real distances from us are enormously
greater than had been supposed. Gradually,
the truth was forced on men's minds that the
terrestrial sphere, so vast in respect to us, is
excessively small compared with most of the
stars which spangle the firmament. Instead
of being the centre of the universe, for whose
benefit all the rest had been created, it is
reduced to the rank of a mere planet, one of a
numerous family, all regularly revolving round
the sun. Moreover, the conditions in which
the planets exist and the circumstances noticeable
on their surfaces, show that some of them
at least may be inhabited, as well as the earth.

Furthermore, the stars which twinkle in
every part of the firmament, are neither more
nor less than suns, of different dimensions,
amongst which our sun is certainly not the
largest. It is more than probable that each of
these suns is accompanied by a system of
planets revolving round him. Planets are the
most reasonable explanation of the phenomena
of variable stars; the most celebrated of which
is Algol, or the star ? of the constellation
Perseus, whose period of variation is extremely
regular. For two days and fourteen hours
it maintains without diminution its greatest
degree of brightness, which is followed by a
gradual weakening of its light, and then by an
equally gradual increase of the same, the whole
of those changes taking place in a little less
than seven hours. It is believed that there is no
actual difference in the quantity of light emitted
by the star itself, but that some opaque body,
such as a very large planet, by revolving round
the star at a short distance from it, screens its
light by passing before it, and so causing a
considerable eclipse. This supposition accords
with the regularity of the phenomenon, and
with the short duration of the partial obscurity
relative to the total duration of the period of
brightness.

Each fixed star being accompanied by planets,
it is a natural inference that some of them may
be inhabited, as are some of the planets belonging
to our own solar system. The distances of
these stars from each other are immense. The
dimensions of our solar system are as nothing
in comparison; and, in the solar system itself,
the earth, which appeared so vast at the outset,
is now known to be a mere point, a tiny speck.

Spectral analysis has been mentioned more
than once in these pages, we therefore do not
now repeat what has been stated before. It is
enough to say, that it is a recently-discovered
mode of investigating the composition of bodies,
by examining the light they emit while burning
or at very high temperatures. Now, without
entering into further detail, it is found
that the heavenly bodies contain substances
exactly the same as those which make up the
solid crust of the earth. Those bodies may
include elementary substances which we have
not; we have some whose presence has not yet
been ascertained in certain stars; but, when
it is found that the sun contains iron in plenty,
besides barium, copper, and zinc in small
quantities; that Aldebaran (the star marked
? in the Bull) has soda, magnesia, hydrogen,
lime, iron, bismuth, tellurium, antimony, and
mercury; that Sirius, the brilliant Dog Star,
likewise confesses to soda, magnesia, hydrogen,
and probably iron; and that many others,
not only of the stars but of the nebulae, have
been made to avow their possession of similar,
if not exactly identical, elements—would it not
be the merest quibble to deny that the universe
is One in material constitution?

The mass and volume of a thing, being
attested by the force it exercises, may be taken
as positive qualities; but its magnitude is quite
relative. Men are colossi for the emmet, puny
dwarfs for the elephant, lilliputian pigmies for
the whale. There is a curious but inseparable
relation between apparent size and actual
distance. By a strange illusion of our senses, the
appearance which any object presents depends
both upon its actual size and on the space
intervening between it and us. If we can
neither touch an object nor get at it in any way,
its actual distance remains unknown, and we
are liable to make the most erroneous estimate
of its real dimensions. At first sight the sun
and moon appear very small compared with
the earth, while the stars might pass for
jets of gas, like those used in illuminating
public buildings. This illusion gave rise to the
once-current opinion that the sun is not bigger
than a barrel, and caused the ancient Greeks
to be laughed at for asserting him to be as
large as the Peloponnesus, the modern Crimea.

But it happens that appreciable size varies
inversely as the distance. The further off a
thing is, the smaller it appears to our senses;
and vice versâ. The rule holds good with the
smallest perceptible objects as well as with the
greatest. The microscope gives us the view of
an object which would be seen by a properly
constituted eye beholding it from the distance
of its object-glass. It gives us a nearer view,
a closer insight, of what we wish to inspect,
and so magnifies it. And were our faculties
not limited, we should doubtless find, upon
still closer inspection, that even the elementary
atoms of which all bodies are composed have
size—even the particles composing air and the
very lightest known substance, hydrogen gas.

The relation between distance and magnitude
is daily forced upon our notice, although
we may be slow to draw from it one inference
touching the constitution of the universe,
namely, that all is small and all is great. It is
true that the adult, as well as the child, may say,

Twinkle, twinkle, little star!
How I wonder what you are,
Up above the world so high,
Like a diamond in the sky!