founded by Alexander--had become
the world centre of the learned from Europe, Asia, and Africa. Its
position was unrivalled. Situated at the mouth of the Nile, it
commanded the Mediterranean Sea, while by means of the Red Sea it held
easy communication with India and Arabia. When Egypt had come under
the sway of Alexander, he had made one of his generals ruler over that
country, and men of intellect collected there to study and to write.
A library was started, and a Greek, Eratosthenes, held the post of
librarian at Alexandria for forty years, namely, from 240-196 B.C.
During this period he made a collection of all the travels and books
of earth description--the first the world had ever known--and stored
them in the Great Library of which he must have felt so justly proud.
But Eratosthenes did more than this. He was the originator of
Scientific Geography. He realised that no maps could be properly laid
down till something was known of the size and shape of the earth.

By this time all men of science had ceased to believe that the world
was flat; they thought of it as a perfect round, but fixed at the centre
in space. Many had guessed at the size of the earth. Some said it was
forty thousand miles round, but Eratosthenes was not content with
guessing. He studied the length of the shadow thrown by the sun at
Alexandria and compared it with that thrown by the sun at Syene, near
the first cataract of the Nile, some five hundred miles distant, and,
as he thought, in the same longitude. The differences in the length
of these two shadows he calculated would represent one-fiftieth of
the circumference of the earth which would accordingly be twenty-five
thousand miles. There was no one to tell him whether he had calculated
right or wrong, but we know to-day that he was wonderfully right. But
he must know more. He must find out how much of this earth was habitable.
To the north and south of the known countries men declared it was too
hot or too cold to live. So he decided that from north to south, that
is, from the land of Thule to the land of Punt (Somaliland), the
habitable earth stretched for some three thousand eight hundred miles,
while from east to west--that is, from the Pillars of Hercules (Straits
of Gibraltar) to India--would be some eight thousand miles. All the
rest was ocean. Ignoring the division of the world into three
continents, he divided it into two, north and south, divided by the
Mediterranean and by a long