s of cometary tracks with meteor streams contained
in a list drawn up in 1878[1216] by Professor Alexander S. Herschel (who
has made the subject peculiarly his own) amounts to seventy-six;
although the four first detected still remain the most conspicuous, and
perhaps the only absolutely sure examples of a relation as significant
as it was, to most astronomers, unexpected.

There had, indeed, been anticipatory ideas. Not that Kepler's comparison
of shooting stars to "minute comets," or Maskelyne's "forse risultera
che essi sono comete," in a letter to the Abate Cesaris, December 12,
1774,[1217] need count for much. But Chladni, in 1819,[1218] considered
both to be fragments or particles of the same primitive matter,
irregularly scattered through space as nebulae; and Morstadt of Prague
suggested about 1837[1219] that the meteors of November might be
dispersed atoms from the tail of Biela's comet, the path of which is cut
across by the earth near that epoch. Professor Kirkwood, however, by a
luminous intuition, penetrated the whole secret, so far as it has yet
been made known. In an article published, or rather buried, in the
_Danville Quarterly Review_ for December, 1861, he argued, from the
observed division of Biela, and other less noted instances of the same
kind, that the sun exercises a "divellent influence" on the nuclei of
comets, which may be presumed to continue its action until their
corporate existence (so to speak) ends in complete pulverisation. "May
not," he continued, "our periodic meteors be the debris of ancient but
now disintegrated comets, whose matter has become distributed round
their orbits?"[1220]

The gist of Schiaparelli's discovery could not be more clearly conveyed.
For it must be borne in mind that with the ultimate destiny of comets'
tails this had nothing to do. The tenuous matter composing them is, no
doubt, permanently lost to the body from which it emanated; but science
does not pretend to track its further wanderings through space. It can,
however, state categorically that these will no longer be conducted
along the paths forsaken under solar compulsion. From the central, and
probably solid parts of comets, on the other hand, are derived the
granules by the swift passage of which our skies are seamed with
periodic fires. It is certain that a loosely agglomerated mass (such as
cometary nuclei most likely are) must gradually separate through the
unequal action of gravity on its various p