curtains were once more drawn about the earth. The glimpses which
adventurous Greeks had obtained of the great outlying universe
were forgotten for a thousand years. The earth became again the
little platform in the centre of a little world, on which men and
women played their little parts, preening themselves on their
superiority to their pagan ancestors.

I do not propose to tell the familiar story of the revival at any
length. As far as the present subject is concerned, it was
literally a Renascence, or re-birth, of Greek ideas.
Constantinople having been taken by the Turks (1453), hundreds of
Greek scholars, with their old literature, sought refuge in
Europe, and the vigorous brain of the young nations brooded over
the ancient speculations, just as the vigorous young brain of
Greece had done two thousand years before. Copernicus (1473-1543)
acknowledges that he found the secret of the movements of the
heavenly bodies in the speculations of the old Greek thinkers.
Galilei (1564-1642) enlarged the Copernican system with the aid
of the telescope; and the telescope was an outcome of the new
study of optics which had been inspired in Roger Bacon and other
medieval scholars by the optical works, directly founded on the
Greek, of the Spanish Moors. Giordano Bruno still further
enlarged the system; he pictured the universe boldly as an
infinite ocean of liquid ether, in which the stars, with retinues
of inhabited planets, floated majestically. Bruno was burned at
the stake (1600); but the curtains that had so long been drawn
about the earth were now torn aside for ever, and men looked
inquiringly into the unfathomable depths beyond. Descartes
(1596-1650) revived the old Greek idea of a gradual evolution of
the heavens and the earth from a primitive chaos of particles,