h's surface is furnished by
observation of an approaching ship at sea. On a clear day a keen eye
may discern the mast and sails rising gradually above the horizon, to be
followed in due course by the hull. Similarly, on approaching the shore,
high objects become visible before those that lie nearer the water. It
is at least a plausible supposition that Pythagoras may have made such
observations as these during the voyage in question, and that therein
may lie the germ of that wonderful conception of the world as a sphere.

To what extent further proof, based on the fact that the earth's shadow
when the moon is eclipsed is always convex, may have been known to
Pythagoras we cannot say. There is no proof that any of the Italic
philosophers made extensive records of astronomical observations as did
the Egyptians and Babylonians; but we must constantly recall that the
writings of classical antiquity have been almost altogether destroyed.
The absence of astronomical records is, therefore, no proof that such
records never existed. Pythagoras, it should be said, is reported to
have travelled in Egypt, and he must there have gained an inkling of
astronomical methods. Indeed, he speaks of himself specifically, in a
letter quoted by Diogenes, as one who is accustomed to study astronomy.
Yet a later sentence of the letter, which asserts that the philosopher
is not always occupied about speculations of his own fancy, suggesting,
as it does, the dreamer rather than the observer, gives us probably a
truer glimpse into the philosopher's mind. There is, indeed, reason to
suppose that the doctrine of the sphericity of the earth appealed to
Pythagoras chiefly because it accorded with his conception that the
sphere is the most perfect solid, just as the circle is the most perfect
plane surface. Be that as it may, the fact remains that we have here, as
far as we can trace its origin, the first expression of the scientific
theory that the earth is round. Had the Italic philosophers accomplished
nothing more than this, their accomplishment would none the less mark an
epoch in the progress of thought.

That Pythagoras was an observer of the heavens is further evidenced by
the statement made by Diogenes, on the authority of Parmenides, that
Pythagoras was the first person who discovered or asserted the identity
of Hesperus and Lucifer--that is to say, of the morning and the evening
star. This was really a remarkable discovery, and one that was