ries
between the first of them and the last, the human intellect was active
in other fields than theirs. Pythagoras had founded a school of
mathematics, and made his experiments on the harmonic intervals. The
Sophists had run through their career. At Athens had appeared
Socrates, Plato, and Aristotle, who ruined the Sophists, and whose
yoke remains to some extent unbroken to the present hour. Within this
period also the School of Alexandria was founded, Euclid wrote his
'Elements' and made some advance in optics. Archimedes had propounded
the theory of the lever, and the principles of hydrostatics. Astronomy
was immensely enriched by the discoveries of Hipparchus, who was
followed by the historically more celebrated Ptolemy. Anatomy had
been made the basis of scientific medicine; and it is said by Draper
that vivisection had begun. [Footnote: 'History of the Intellectual
Development of Europe,' p. 295.] In fact, the science of ancient Greece
had already cleared the world of the fantastic images of divinities
operating capriciously through natural phenomena. It had shaken itself
free from that fruitless scrutiny 'by the internal light of the mind
alone,' which had vainly sought to transcend experience, and to reach
a knowledge of ultimate causes. Instead of accidental observation, it
had introduced observation with a purpose; instruments were employed
to aid the senses; and scientific method was rendered in a great measure
complete by the union of Induction and Experiment.

What, then, stopped its victorious advance? Why was the scientific
intellect compelled, like an exhausted soil, to lie fallow for nearly
two millenniums, before it could regather the elements necessary to
its fertility and strength? Bacon has already let us know one cause;
Whewell ascribes this stationary period to four causes--obscurity of
thought, servility, intolerance of disposition, enthusiasm of temper;
and he gives striking examples of each. [Footnote: 'History of the
Inductive Sciences,' vol. i.] But these characteristics must have
had their antecedents in the circumstances of the time. Rome, and the
other cities of the Empire, had fallen into moral putrefaction.
Christianity had appeared, offering the Gospel to the poor, and by
moderation, if not asceticism of life, practically protesting against
the profligacy of the age. The sufferings of the early Christians,
and the extraordinary exaltation of mind which enabled them to trium