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...