In the period I have chosen to bring before the reader, civilization was on the decline, and progress imperceptible, but the germs of a riper growth were still existent, concealed within the spreading darkness of medievalism. When Grecian science and philosophy seemed to stand on the threshold of modern enlightenment the pall of despotism and superstition descended on the earth and stifled every impulse of progress for more than fifteen centuries. The Yggdrasil of Christian superstition spread its roots throughout the Roman Empire, strangling alike the nascent ethics of Christendom, and the germinating science of the ancient world. Had the leading minds of that epoch, instead of ex­pending their zeal and acumen on theological inanities, applied themselves to the study of nature, they might have forestalled the march of the centuries, and advanced us a thousand years beyond the present time. But the atmosphere of the period was charged with a metaphysical mysticism whereby all philosophic thought and material research were arrested. The records of a millennium comprise little more than the rise, the progress, and the triumph of superstition and barbarism. The degenerate Greeks became the serfs and slaves of the land in which they were formerly the masters, and retreated gradually to a vanishing point in the vast district from the Adriatic to the Indus, over which the eagle-wing of Alexander had swept in uninterrupted conquest. Unable to oppose their political solidarity and martial science to the fanaticism of the half-armed Saracens, they yielded up to them insensibly their faith and their empire, and their place was filled by a host of unprogressive Mohammedans, who brought with them a newer religion more sensuous in its conceptions, but less gross in its practice, than the Christianity of that day. But the hardy barbarians of the North, drinking at the fountain of knowledge, had achieved some political organization, and became the natural and irresistible barriers against which the waves of Moslem enthusiasm dashed themselves in vain. The term of Asiatic encroachment was fixed at the Pyrenees in the west, and at the Danube in the east by the valorous Franks and Hungarians; and on the brink of the turning tide stand the heroic figures of Charles Martel and Matthias Corvinus. Civilization has now included almost the whole globe in its comprehensive embrace; both the old world and the new have been overrun by the intellectual heirs of the Greeks; in every land the extinction of retrograde races proceeds with measured certainty, and we appear to be safer from a returning flood of barbarism than from some astronomical catastrophe. The mediaeval order of things is reversed, the ravages of Attila reappear under a new aspect, and the descendants of the Han and the Hun alike are raised by the hand, or crushed under the foot of aggressive civilization...