ipparchus was the dominant
scientific personality of his century. What he believed became as a law
to his immediate successors. His tenets were accepted as final by
their great popularizer, Ptolemy, three centuries later; and so the
heliocentric theory of Aristarchus passed under a cloud almost at the
hour of its dawning, there to remain obscured and forgotten for the
long lapse of centuries. A thousand pities that the greatest observing
astronomer of antiquity could not, like one of his great precursors,
have approached astronomy from the stand-point of geography and poetry.
Had he done so, perhaps he might have reflected, like Aristarchus
before him, that it seems absurd for our earth to hold the giant sun
in thraldom; then perhaps his imagination would have reached out to the
heliocentric doctrine, and the cobweb hypothesis of epicycles, with that
yet more intangible figment of the perfect circle, might have been wiped
away.

But it was not to be. With Aristarchus the scientific imagination had
reached its highest flight; but with Hipparchus it was beginning to
settle back into regions of foggier atmosphere and narrower horizons.
For what, after all, does it matter that Hipparchus should go on to
measure the precise length of the year and the apparent size of the
moon's disk; that he should make a chart of the heavens showing the
place of 1080 stars; even that he should discover the precession of
the equinox;--what, after all, is the significance of these details as
against the all-essential fact that the greatest scientific authority of
his century--the one truly heroic scientific figure of his epoch--should
have lent all the forces of his commanding influence to the old, false
theory of cosmology, when the true theory had been propounded and when
he, perhaps, was the only man in the world who might have substantiated
and vitalized that theory? It is easy to overestimate the influence of
any single man, and, contrariwise, to underestimate the power of the
Zeitgeist. But when we reflect that the doctrines of Hipparchus,
as promulgated by Ptolemy, became, as it were, the last word of
astronomical science for both the Eastern and Western worlds, and so
continued after a thousand years, it is perhaps not too much to say
that Hipparchus, "the lover of truth," missed one of the greatest
opportunities for the promulgation of truth ever vouchsafed to a devotee
of pure science.

But all this, of course, detracts nothing fr