to our modern
minds. But in the fifteenth century, when men were getting their first
inklings of critical scholarship, and when the practical question of an
ocean voyage to Asia was pressing for solution, such a point could no
longer fail to attract attention; and it happened fortunately that the
wet theory, no less than the dry theory, had a popular advocate among
those classical authors to whose authority so much deference was paid.

[Footnote 359: Just as our grandfathers used to read the Bible
without noticing such points as the divergences between the
books of Kings and Chronicles, the contradictions between the
genealogies of Jesus in Matthew and Luke, the radically
different theories of Christ's personality and career in the
Fourth Gospel as compared with the three Synoptics, etc.]

[Sidenote: Ancient theory of the five zones.]

[Sidenote: The Inhabited World and the Antipodes.]

If the Portuguese mariners of the generation before Columbus had
acquiesced in Ptolemy's views as final, they surely would not have
devoted their energies to the task of circumnavigating Africa. But there
were yet other theoretical or fanciful obstacles in the way. When you
look at a modern map of the world, the "five zones" may seem like a mere
graphic device for marking conveniently the relations of different
regions to the solar source of heat; but before the great Portuguese
voyages and the epoch-making third voyage of Vespucius, to be described
hereafter, a discouraging doctrine was entertained with regard to these
zones. Ancient travellers in Scythia and voyagers to "Thule"--which in
Ptolemy's scheme perhaps meant the Shetland isles[360]--had learned
something of Arctic phenomena. The long winter nights,[361] the snow and
ice, and the bitter winds, made a deep impression upon visitors from the
Mediterranean;[362] and when such facts were contrasted with the
scorching blasts that came from Sahara, the resulting theory was
undeniably plausible. In the extreme north the ocean must be frozen and
the country uninhabitable by reason of the cold; contrariwise, in the
far south the ocean must be boiling hot and the country inhabitable only
by gnomes and salamanders. Applying these ideas to the conception of the
earth as a sphere, Pomponius Mela tells us that the surface of the
sphere is divided into five zones, of which only two are fit to support
human life. About each pole stretche