the Sea of Darkness for nearly 12,000
miles, the real distance from the Canaries to Japan. It was a case where
the littleness of the knowledge was not a dangerous but a helpful thing.
If instead of the somewhat faulty astronomy of Ptolemy and the very hazy
notions prevalent about "the Indies," the correct astronomy of
Toscanelli had prevailed and had been joined to an accurate knowledge of
eastern Asia, Columbus would surely never have conceived his great
scheme, and the discovery of America would probably have waited to be
made by accident.[465] The whole point of his scheme lay in its promise
of a shorter route to the Indies than that which the Portuguese were
seeking by way of Guinea. Unless it was probable that it could furnish
such a shorter route, there was no reason for such an extraordinary
enterprise.

[Footnote 465: See below, vol. ii. p. 96.]

* * * * *

[Sidenote: Columbus's speculations on climate.]

[Sidenote: His voyage to Guinea.]

[Sidenote: His voyage into the Arctic ocean, 1477.]

The years between 1474 and 1480 were not favourable for new maritime
ventures on the part of the Portuguese government. The war with Castile
absorbed the energies of Alfonso V. as well as his money, and he was
badly beaten into the bargain. About this time Columbus was writing a
treatise on "the five habitable zones," intended to refute the old
notions about regions so fiery or so frozen as to be inaccessible to
man. As this book is lost we know little or nothing of its views and
speculations, but it appears that in writing it Columbus utilized sundry
observations made by himself in long voyages into the torrid and arctic
zones. He spent some time at the fortress of San Jorge de la Mina, on
the Gold Coast, and made a study of that equinoctial climate.[466] This
could not have been earlier than 1482, the year in which the fortress
was built. Five years before this he seems to have gone far in the
opposite direction. In a fragment of a letter or diary, preserved by his
son and by Las Casas, he says:--"In the month of February, 1477, I
sailed a hundred leagues beyond the island of Thule, [to?] an island of
which the south part is in latitude 73 deg., not 63 deg., as some say; and it
[i. e. Thule] does not lie within Ptolemy's western boundary, but much
farther west. And to this island, which is as big as England, the
English go with their wares, especially from Bristol. When I was