modified notion of
Homer's Ocean River, which had been ridiculed and rejected by Herodotus;
for he describes the habitable earth as a great oval island, surrounded by
the ocean, terminated on the west by the river Tartessius, (supposed to be
the Guadelquiver,) on the east by the Indus, and on the north by Albion and
Ierne, of which islands his ideas were necessarily very vague and
imperfect. In some other respects, however, his knowledge was more
accurate: he coincides with Herodotus in his description of the Caspian
Sea, and expressly states that it ought to be called a great lake, not a
sea. A short period before Aristotle flourished, that branch of geography
which relates to the temperature of different climates, and other
circumstances affecting health, was investigated with considerable
diligence, ingenuity, and success, by the celebrated physician Hippocrates.
In the course of his journeys, with this object in view, he seems to have
followed the plan and the route of Herodotus, and sometimes to have even
penetrated farther than he did.

Pytheas, of Marseilles, lived a short time before Alexander the Great: he
is celebrated for his knowledge in astronomy, mathematics, philosophy, and
geography, and for the ardour and perseverance with which either a strong
desire for information, or the characteristic commercial spirit of his
townspeople, or both united, carried him forward in the path of maritime
discovery. The additions, however, which he made to geography as a science,
or to the sciences intimately connected with it, are more palpable and
undisputed, than the extent and discoveries of his voyages.

He was the first who established a distinction of climate by the length of
days and nights: and he is said to have discovered the dependence of the
tides upon the position of the moon, affirming that the flood-tide depended
on the increase of the moon, and the ebb on its decrease. By means of a
gnomon he observed, at the summer solstice at Marseilles, that the length
of the shadow was to the height of the gnomon as 120 to 41-1/5; or, in
other words, that the obliquity of the ecliptic was 23:50. He relates, that
in the country which he reached in his voyage to the north, the sun, at the
time of the summer solstice, touched the northern part of the horizon: he
pointed out three stars near the pole, with which the north star formed a
square; and within this square, he fixed the true place of the pole.
According to Strab