they thought the sky was a solid blue concave, studded with blazing
points, an empire of fate, the gold-and-azure floor of the abode of
gods and spirits. Now all that is dissolved away; the wandering planets
become at will broad disks, like sisters of the moon; and countless
millions of stars are now mirrored in the same retina with which the
Magi saw the few thousands of the firmament that were visible from the
plains of Chaldea.

Once men were aware of nothing in the earth beneath its hills and
valleys and teeming soil. Now they walk consciously over the ruins
of old worlds; they can decipher the strange characters and read the
strange history graven on these gigantic tablets. The stony veil is
rent, and they can look inimitable periods back, and see the curious
animals which then moved up and down in the earth.

Once a glass bubble was a wonder for magnifying power. Now the lenses of
the microscope bring an inverted universe to light. Men can look into a
drop and discover an ocean crowded with millions of living creatures,
monsters untypified in the visible world, playing about as in a great
deep.

Once a Roman emperor prized a mysterious jewel because it brought the
gladiators contending in the arena closer to the imperial canopy. Now
observatories, with their revolving domes, crown the heights at every
centre of civilization, and the mighty telescope, poised on exquisite
mechanism, turns infinite space into a Coliseum, brings its invisible
luminaries close to the astronomer's seat, and reveals the harmonies and
splendors of those distant works of God.

Once the supposed elements were fire, and water, and earth, and air;