cool summer retreat of the Persian kings, was
defended by seven encircling walls of hewn and polished blocks, the
interior ones in succession of increasing height, and of different
colors, in astrological accordance with the seven planets. The palace
was roofed with silver tiles, its beams were plated with gold. At
midnight, in its halls the sunlight was rivaled by many a row of naphtha
cressets. A paradise--that luxury of the monarchs of the East--was
planted in the midst of the city. The Persian Empire, from the
Hellespont to the Indus, was truly the garden of the world.

EFFECTS ON THE GREEK ARMY. I have devoted a few pages to the story of
these marvelous campaigns, for the military talent they fostered led
to the establishment of the mathematical and practical schools of
Alexandria, the true origin of science. We trace back all our exact
knowledge to the Macedonian campaigns. Humboldt has well observed that
an introduction to new and grand objects of Nature enlarges the human
mind. The soldiers of Alexander and the hosts of his camp-followers
encountered at every march unexpected and picturesque scenery. Of all
men, the Greeks were the most observant, the most readily and profoundly
impressed. Here there were interminable sandy plains, there mountains
whose peaks were lost above the clouds. In the deserts were mirages,
on the hill-sides shadows of fleeting clouds sweeping over the forests.
They were in a land of amber-colored date-palms and cypresses, of
tamarisks, green myrtles, and oleanders. At Arbela they had fought
against Indian elephants; in the thickets of the Caspian they had roused
from his lair the lurking royal tiger. They had seen animals which,
compared with those of Europe, were not only strange, but colossal--the
rhinoceros, the hippopotamus, the camel, the crocodiles of the Nile
and the Ganges. They had encountered men of many complexions and many
costumes: the swarthy Syrian, the olive-colored Persian, the black
African. Even of Alexander himself it is related that on his death-bed
he caused his admiral, Nearchus, to sit by his side, and found
consolation in listening to the adventures of that sailor--the story of
his voyage from the Indus up the Persian Gulf. The conqueror had seen
with astonishment the ebbing and flowing of the tides. He had built
ships for the exploration of the Caspian, supposing that it and
the Black Sea might be gulfs of a great ocean, such as Nearchus had
discovered the Per