to this question is in the affirmative. There appears to be
no special size suited to the vastness of space; we find, as a matter of
fact, bodies of all manner of sizes, ranging by gradations from the most
tremendous suns, like Sirius, down through ordinary suns to smaller
ones, then to planets of all sizes, satellites still smaller, then the
asteroids, till we come to the smallest satellite of Mars, only about
ten miles in diameter, and weighing only some billion tons--the smallest
of the regular bodies belonging to the solar system known.

But, besides all these, there are found to occur other masses, not much
bigger and some probably smaller, and these we call comets when we see
them. Below these, again, we find masses varying from a few tons in
weight down to only a few pounds or ounces, and these when we see them,
which is not often, we call meteors or shooting-stars; and to the size
of these meteorites there would appear to be no limit: some may be
literal grains of dust. There seems to be a regular gradation of size,
therefore, ranging from Sirius to dust; and apparently we must regard
all space as full of these cosmic particles--stray fragments, as it
were, perhaps of some older world, perhaps going to help to form a new
one some day. As Kepler said, there are more "comets" in the sky than
fish in the sea. Not that they are at all crowded together, else they
would make a cosmic haze. The transparency of space shows that there
must be an enormous proportion of clear space between each, and they are
probably much more concentrated near one of the big bodies than they are
in interstellar space.[30] Even during the furious hail of meteors in
November 1866 it was estimated that their average distance apart in the
thickest of the shower was 35 miles.

Consider the nature of a meteor or shooting-star. We ordinarily see them
as a mere streak of light; sometimes they leave a luminous tail behind
them; occasionally they appear as an actual fire-ball, accompanied by an
explosion; sometimes, but very seldom, they are seen to drop, and may
subsequently be dug up as a lump of iron or rock, showing signs of rough
treatment by excoriation and heat. These last are the meteorites, or
siderites, or aerolites, or bolides, of our museums. They are popularly
spoken of as thunderbolts, though they have nothing whatever to do with
atmospheric electricity.

[Illustration: FIG. 95.--Meteorite.]

They appear to be travelling rocky or