to its own height at the same
moment. It remains then but to measure the length of this shadow to
determine the height of the object. Such feats as this evidence the
practicality of the genius of Thales. They suggest that Greek science,
guided by imagination, was starting on the high-road of observation. We
are told that Thales conceived for the first time the geometry of lines,
and that this, indeed, constituted his real advance upon the Egyptians.
We are told also that he conceived the eclipse of the sun as a purely
natural phenomenon, and that herein lay his advance upon the Chaldean
point of view. But if this be true Thales was greatly in advance of his
time, for it will be recalled that fully two hundred years later
the Greeks under Nicias before Syracuse were so disconcerted by the
appearance of an eclipse, which was interpreted as a direct omen and
warning, that Nicias threw away the last opportunity to rescue his army.
Thucydides, it is true, in recording this fact speaks disparagingly of
the superstitious bent of the mind of Nicias, but Thucydides also was a
man far in advance of his time.

All that we know of the psychology of Thales is summed up in the famous
maxim, "Know thyself," a maxim which, taken in connection with
the proven receptivity of the philosopher's mind, suggests to us a
marvellously rounded personality.

The disciples or successors of Thales, Anaximander and Anaximenes, were
credited with advancing knowledge through the invention or introduction
of the sundial. We may be sure, however, that the gnomon, which is the
rudimentary sundial, had been known and used from remote periods in
the Orient, and the most that is probable is that Anaximander may
have elaborated some special design, possibly the bowl-shaped sundial,
through which the shadow of the gnomon would indicate the time. The same
philosopher is said to have made the first sketch of a geographical map,
but this again is a statement which modern researches have shown to be
fallacious, since a Babylonian attempt at depicting the geography of
the world is still preserved to us on a clay tablet. Anaximander may,
however, have been the first Greek to make an attempt of this kind. Here
again the influence of Babylonian science upon the germinating Western
thought is suggested.

It is said that Anaximander departed from Thales's conception of the
earth, and, it may be added, from the Babylonian conception also, in
that he conceived it as