Not without interest do we still look on specimens of their method of printing.  Upon a revolving roller they engraved, in cuneiform letters, their records, and, running this over plastic clay formed into blocks, produced ineffaceable proofs.  From their tile-libraries we are still to reap a literary and historical harvest.  They were not without some knowledge of optics.  The convex lens found at Nimroud shows that they were not unacquainted with magnifying instruments.  In arithmetic they had detected the value of position in the digits, though they missed the grand Indian invention of the cipher.

What a spectacle for the conquering Greeks, who, up to this time, had neither experimented nor observed!  They had contented themselves with mere meditation and useless speculation.

Its religious condition.  But Greek intellectual development, due thus in part to a more extended view of Nature, was powerfully aided by the knowledge then acquired of the religion of the conquered country.  The idolatry of Greece had always been a horror to Persia, who, in her invasions, had never failed to destroy the temples and insult the fanes of the bestial gods.  The impunity with which these sacrileges had been perpetrated had made a profound impression, and did no little to undermine Hellenic faith.  But now the worshiper of the vile Olympian divinities, whose obscene lives must have been shocking to every pious man, was brought in contact with a grand, a solemn, a consistent religious system having its foundation on a philosophical basis.  Persia, as is the case with all empires of long duration, had passed through many changes of religion.  She had followed the Monotheism of Zoroaster; had then accepted Dualism, and exchanged that for Magianism.  At the time of the Macedonian expedition, she recognized one universal Intelligence, the Creator, Preserver, and Governor of all things, the most holy essence of truth, the giver of all good.  He was not to be represented by any image, or any graven form.  And, since, in every thing here below, we see the resultant of two opposing forces, under him were two coequal and coeternal principles, represented by the imagery of Light and Darkness.  These principles are in never-ending conflict.  The world is their battle-ground, man is their prize.

In the old legends of Dualism, the Evil Spirit was said to have sent a serpent to ruin the paradise which the Good Spirit had made.  These legends became known to the Jews during their Babylonian captivity.

The existence of a principle of evil is the necessary incident of the existence of a principle of good, as a shadow is the necessary incident of the presence of light.  In this manner could be explained the occurrence of evil in a world, the maker and ruler of which is supremely good.  Each of the personified principles of light and darkness, Ormuzd and Ahriman, had his subordinate angels, his counselors, his armies.  It is the duty of a good man to cultivate truth, purity, and industry.  He may look forward, when this life is over, to a life in another world, and trust to a resurrection of the body, the immortality of the soul, and a conscious future existence.