m
Aristotle alludes were discussing, as a matter of theory, this same
subject. Eratosthenes held that it would be easy enough to sail from
Spain to India on the same parallel were it not for the vast extent of
the Atlantic ocean.[449] On the other hand, Seneca maintained that the
distance was probably not so very great, and that with favouring winds a
ship might make the voyage in a few days.[450] In one of his tragedies
Seneca has a striking passage[451] which has been repeatedly quoted as
referring to the discovery of America, and is certainly one of the most
notable instances of prophecy on record. There will come a time, he
says, in the later years, when Ocean shall loosen the bonds by which we
have been confined, when an immense land shall lie revealed, and Tethys
shall disclose new worlds, and Thule will no longer be the most remote
of countries. In Strabo there is a passage, less commonly noticed, which
hits the truth--as we know it to-day--even more closely. Having argued
that the total length of the Inhabited World is only about a third part
of the circumference of the earth in the temperate zone, he suggests it
as possible, or even probable, that within this space there may be
another Inhabited World, or even more than one; but such places would be
inhabited by different races of men, with whom the geographer, whose
task it is to describe the _known_ world, has no concern.[452] Nothing
could better illustrate the philosophical character of Strabo's mind. In
such speculations, so far as his means of verification went, he was
situated somewhat as we are to-day with regard to the probable
inhabitants of Venus or Mars.

[Footnote 447: It was formerly assumed, without hesitation,
that the letter from Toscanelli to Columbus was written and
sent in 1474. The reader will observe, however, that while the
enclosed letter to Martinez is dated June 25, 1474, the letter
to Columbus, in which it was enclosed, has no date. But
according to the text as given in _Vita dell' Ammiraglio_, cap.
viii., this would make no difference, for the letter to
Columbus was sent only a few days later than the original
letter to Martinez: "I send you a copy of another letter, which
I wrote a few days ago (_alquanti giorni fa_) to a friend of
mine, a gentleman of the household of the king of Portugal
before the wars of Castile, in reply