on to the water towards the antarctic pole, which it was known to
have at the arctic. He concluded likewise that all the five zones of the
earth were inhabited, of which opinion he was the more firmly persuaded
after he had sailed into 75 degrees of north latitude. He also concluded
that, as the Portuguese had sailed to the southwards, the same might be
done to the westwards, where in all reason land ought to be found: And
having collected all the tokens that had been observed by mariners, which
made for his purpose, he became perfectly satisfied that there were many
lands to the westwards of Cabo Verde and the Canaries, and that it was
practicable to sail over the ocean for their discovery; because, since the
world is round, all its parts must necessarily be so likewise. All the
earth is so fixed that it can never fail; and the sea, though shut in by
the land, preserves its rotundity, without ever falling away, being
preserved in its position by attraction towards the centre of gravity. By
the consideration of many natural reasons, and by perceiving that not
above the third part of a great circle of the sphere was discovered, being
the extent eastwards from Cabo Verde to the farthest then known land of
India, he concluded that there remained much room for farther discoveries
by sailing to the westwards, till they should come to meet with those
lands then known, the ends whereof to the eastwards had not been yet
explored. In this opinion he was much confirmed by his friend Martin de
Bohemia[1], a Portuguese and an able cosmographer, a native of the island
of Fayal.

Many other circumstances concurred to encourage Columbus in the mighty
enterprize of discovery towards the west, by discoursing with those who
used to sail to the westwards, particularly to the islands of the Azores.
In particular, Martin Vincente assured him, that, having been on one
occasion 450 leagues to the westwards of Cape St Vincent, he took up a
piece of wood which was very artificially wrought, and yet was supposed
not to have been fashioned with tools of iron: And, because the wind had
blown many days from the west, he inferred that this piece of wood must
have drifted from some land in that direction. Peter Correa, who had
married the sister of Columbuses wife, likewise assured him, that he had
seen another piece of wood similarly wrought, which had been drifted by
the west winds upon the island of Puerto Santo; and that canes also had
been floate