For a considerable period after the time of Herodotus, the ancients seem to have been nearly stationary in their knowledge of the world.  About 368 years before Christ, Eudoxus, of Cnidus, whose desire of studying astronomy induced him to visit Egypt, Asia, and Italy, who first attempted to explain the planetary motions, and who is said to have discovered the inclination of the moon’s orbit, and the retrograde motion of her nodes, is celebrated as having first applied geographical observations to astronomy; but he does not appear to have directed his researches or his conjectures towards the figure or the circumference of the earth, or the distances or relative situations of any places on its surface.

Nearly about the same period that Eudoxus died Aristotle flourished.  This great philosopher, collecting and combining into one system of geographical knowledge the discoveries and observations of all who had preceded him, stamped on them a dignity and value they had not before possessed, as well as rendered them less liable to be forgotten or misapplied:  he inferred the sphericity of the earth from the observations of travellers, that the stars seen in Greece were not visible in Cyprus or Egypt; and thus established the fundamental principle of all geography.  But though this science, in its most important branch, derived much benefit from his powerful mind, yet it was not advanced in its details.  He supposed the coasts of Spain not very distant from those of India; and he even embraced a 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.