(1.) Ptolemy's "Habitable Quarter" of the world, amounting to just half
the longitude of the globe, was literally accepted by the Moslem world,
as it accepted the Pentateuch from the moment when it began its study of
science at the Court of Almamoun (813-833). But, as the conquests of the
Caliphs disclosed districts in the east far beyond Ptolemy's limits, it
was necessary, in case of keeping his data for the whole, to compress
the part which alone was to be found fully described in his chart: "On
the west, unhappily, there were no countries newly discovered to
compensate for this abridgment." By Massoudy's time,--by the tenth
century,--fact and theory were thus hopelessly at variance.

(2.) On the shape of Africa, the mass of Arabic opinion confirmed
Ptolemy, but among the more enlightened there is traceable from
Massoudy's time a tendency either to react towards Strabo's partly
agnostic position, or to invent some new theory rather more in harmony
with the known facts. That is, either their later map-makers cut off
Africa at Cape Non or Bojador and Cape Guardafui, and gave away the rest
to the "Green Sea of Darkness," or, like Massoudy, they sketched a great
Southern Continent, divided from Africa by a narrow channel, which
connected the Western Ocean with the Sea of Habasch--of Abyssinia or
India. In either case Africa was left an island.

(3.) The words "Gog and Magog" from Jeremiah, describing the nomades of
Central Asia, appear in the Koran as Yadjoudj and Madjoudj. The complete
story, in the tenth century and in Edrisi's day, connects them with
Alexander the Great, who is also found in the Koran as Doul-Carnain, and
with the Wall of China. "When the Conqueror," said the Arabs, "reached
the place near where the sun rose, he was implored to build a wall to
shut off the marauders of Yadjoudj and Madjoudj from the rich countries