to be itself a compound, there will still remain the yet finer
particles of the nous of Anaxagoras to baffle the most subtle analysis
of which to-day's science gives us any pre-vision. All in all, then,
the work of Anaxagoras must stand as that of perhaps the most far-seeing
scientific imagination of pre-Socratic antiquity.

LEUCIPPUS AND DEMOCRITUS

But we must not leave this alluring field of speculation as to the
nature of matter without referring to another scientific guess, which
soon followed that of Anaxagoras and was destined to gain even wider
fame, and which in modern times has been somewhat unjustly held to
eclipse the glory of the other achievement. We mean, of course, the
atomic theory of Leucippus and Democritus. This theory reduced all
matter to primordial elements, called atoms (gr atoma) because they are
by hypothesis incapable of further division. These atoms, making up the
entire material universe, are in this theory conceived as qualitatively
identical, differing from one another only in size and perhaps in shape.
The union of different-sized atoms in endless combinations produces the
diverse substances with which our senses make us familiar.

Before we pass to a consideration of this alluring theory, and
particularly to a comparison of it with the theory of Anaxagoras, we
must catch a glimpse of the personality of the men to whom the theory
owes its origin. One of these, Leucippus, presents so uncertain a figure
as to be almost mythical. Indeed, it was long questioned whether such
a man had actually lived, or whether he were not really an invention
of his alleged disciple, Democritus. Latterday scholarship, however,
accepts him as a real personage, though knowing scarcely more of him
than that he was the author of the famous theory with which his name
was associated. It is suggested that he was a wanderer, like most
philosophers of his time, and that later in life he came to Abdera, in
Thrace, and through this circumstance became the teacher of Democritus.
This fable answers as well as another. What we really know is that
Democritus himself, through whose writings and teachings the atomic
theory gained vogue, was born in Abdera, about the year 460 B.C.--that
is to say, just about the time when his great precursor, Anaxagoras,
was migrating to Athens. Democritus, like most others of the early Greek
thinkers, lives in tradition as a picturesque figure. It is vaguely
reported that he travelled for