ewton had predicted
and shown to be recurrent at intervals of thirty-three years, showed
that meteors are not mere sporadic swarms of matter flying at random,
but exist in isolated swarms, and sweep about the sun in regular
elliptical orbits.

Presently it was shown by the Italian astronomer Schiaparelli that
one of these meteor swarms moves in the orbit of a previously observed
comet, and other coincidences of the kind were soon forthcoming. The
conviction grew that meteor swarms are really the debris of comets; and
this conviction became a practical certainty when, in November, 1872,
the earth crossed the orbit of the ill-starred Biela, and a shower of
meteors came whizzing into our atmosphere in lieu of the lost comet.

And so at last the full secret was out. The awe-inspiring comet, instead
of being the planetary body it had all along been regarded, is really
nothing more nor less than a great aggregation of meteoric particles,
which have become clustered together out in space somewhere, and which
by jostling one another or through electrical action become luminous. So
widely are the individual particles separated that the cometary body as
a whole has been estimated to be thousands of times less dense than the
earth's atmosphere at sea-level. Hence the ease with which the comet may
be dismembered and its particles strung out into streaming swarms.

So thickly is the space we traverse strewn with this cometary dust
that the earth sweeps up, according to Professor Newcomb's estimate, a
million tons of it each day. Each individual particle, perhaps no larger
than a millet seed, becomes a shooting-star, or meteor, as it burns to
vapor in the earth's upper atmosphere. And if one tiny planet sweeps
up such masses of this cosmic matter, the amount of it in the entire
stretch of our system must be beyond all estimate. What a story it tells
of the myriads of cometary victims that have fallen prey to the sun
since first he stretched his planetary net across the heavens!

THE FIXED STARS

When Biela's comet gave the inhabitants of the earth such a fright in
1832, it really did not come within fifty millions of miles of us. Even
the great comet through whose filmy tail the earth passed in 1861 was
itself fourteen millions of miles away. The ordinary mind, schooled to
measure space by the tiny stretches of a pygmy planet, cannot grasp the
import of such distances; yet these are mere units of measure compared
with the vast