ellectual centre than
had perhaps ever before been granted to any city, with the possible
exception of Babylon.

EUCLID (ABOUT 300 B.C.)

Our present concern is with that first wonderful development of
scientific activity which began under the first Ptolemy, and which
presents, in the course of the first century of Alexandrian influence,
the most remarkable coterie of scientific workers and thinkers that
antiquity produced. The earliest group of these new leaders in science
had at its head a man whose name has been a household word ever since.
This was Euclid, the father of systematic geometry. Tradition has
preserved to us but little of the personality of this remarkable
teacher; but, on the other hand, his most important work has come down
to us in its entirety. The Elements of Geometry, with which the name
of Euclid is associated in the mind of every school-boy, presented the
chief propositions of its subject in so simple and logical a form that
the work remained a textbook everywhere for more than two thousand
years. Indeed it is only now beginning to be superseded. It is not
twenty years since English mathematicians could deplore the fact that,
despite certain rather obvious defects of the work of Euclid, no better
textbook than this was available. Euclid's work, of course, gives
expression to much knowledge that did not originate with him. We have
already seen that several important propositions of geometry had been
developed by Thales, and one by Pythagoras, and that the rudiments of
the subject were at least as old as Egyptian civilization. Precisely how
much Euclid added through his own investigations cannot be ascertained.
It seems probable that he was a diffuser of knowledge rather than an
originator, but as a great teacher his fame is secure. He is credited
with an epigram which in itself might insure him perpetuity of fame:
"There is no royal road to geometry," was his answer to Ptolemy when
that ruler had questioned whether the Elements might not be simplified.
Doubtless this, like most similar good sayings, is apocryphal; but
whoever invented it has made the world his debtor.

HEROPHILUS AND ERASISTRATUS

The catholicity of Ptolemy's tastes led him, naturally enough, to
cultivate the biological no less than the physical sciences. In
particular his influence permitted an epochal advance in the field of
medicine. Two anatomists became famous through the investigations they
were permitted to make un