Only a few years ago this earth was considered the real center of the universe; all the stars were supposed to revolve around this insignificant atom. The German mind, more than any other, has done away with this piece of egotism. Purbach and Mullerus, in the fifteenth century, contributed most to the advancement of astronomy in their day. To the latter the world is indebted for the introduction of decimal fractions, which completed our arithmetical notation, and formed the second of the three steps by which, in modern times, the science of numbers has been so greatly improved; and yet both of these men believed in the most childish absurdities--at least in enough of them to die without their orthodoxy having ever been questioned. Next came the great Copernicus, and he stands at the head of the heroic thinkers of his time, who had the courage and the mental strength to break the chains of prejudice, custom and authority, and to establish truth on the basis of experience, observation and reason. He removed the earth, so to speak, from the center of the universe, and ascribed to it a twofold motion, and demonstrated the true position which it occupies in the solar system. At his bidding the earth began to revolve. At the command of his genius it commenced its grand flight amid the eternal constellations around the sun. For fifty years his discoveries were disregarded. All at once, by the exertions of Galileo, they were kindled into so grand a conflagration as to consume the philosophy of Aristotle, to alarm the hierarchy of Rome, and to threaten the existence of every opinion not founded upon experience, observation and reason. The earth was no longer considered a universe governed by the caprices of some revengeful Deity, who had made the stars out of what he had left after completing the world, and had stuck them in the sky simply to adorn the night. I have said this much concerning astronomy because it was the first splendid step forward! The first sublime blow that shattered the lance and shivered the shield of superstition; the first real help that man received from heaven. Because it was the first great lever placed beneath the altar of a false religion; the first revelation of the infinite to man, the first authoritative declaration that the universe is governed by law; the first science that gave the lie direct to the cosmogony of barbarism; and because it is the sublimest victory that reason has achieved. In speaking of astronomy I have confined myself to the discoveries made since the revival of learning. Long ago, on the banks of the Ganges, ages before Copernicus lived, Aryabhatta taught that the earth is a sphere and revolves on its own axis. This, however, does not detract from the glory of the great German. The discovery of the Hindoo had been lost in the midnight of Europe--in the age of faith--and Copernicus was as much a discoverer as though Aryabhatta had never lived.