The history of civilization is written in the triumphs which are won by scientific invention over the physical laws of nature, and over the mental infirmities of inferior human tribes. These multiply at points in space, and periods of time, most happily adapted to promote the progress and welfare of mankind. The manufacture of glass windows, chimneys, clocks, paper, the mariner's compass, fire-arms, watches, and saw-mills, with the process of printing with movable types, and the use of the telescope, comprise nearly all the inventions of importance which were made during the lapse of twelve centuries; all the best of which appeared near the close of the mediæval period, and were not a little indebted to information obtained from Mohammedans through the crusades. In the gradual development of human destiny occur flourishing periods, when numerous men of genius are clustered together with mutual dependence, and in a narrow space. For instance, Tycho, the founder of the new measuring system of astronomy, Kepler, Galileo, and Lord Bacon of Verulam, were cotemporaries; and all of them, except the first, lived to see the works of Descartes and Fermat. The true celestial system was discovered by Copernicus in the same year in which Columbus died, fourteen years after the grandest mundane discovery was made. The sudden appearance and disappearance of three new stars which occurred in 1572, 1600, and 1604, excited the wonder of vast assemblies of people, all over Europe, while humble artizans, in an obscure corner thereof, were constructing an instrument which should at once calm their fears and excite the most absorbing astonishment. The telescope was discovered in Holland, in 1608, and two years after the immortal Florentine astronomer began to shine prominently above all other leaders of sublime science. Galileo was the Huss of mediæval progress, if it be not better to call him the Columbus. The day of predestined freedom rose over his cradle, and his life-struggle struck the hour. His hand kindled brighter lamps in the great temple of knowledge, and, sublime priest of true evangelism as he was, it was fitting that his place and mission were so central, when he held aloft supremest light. We love to read the history of his mighty spirit, and contemplate the serene old man, blinded by gazing at stars, bereaved of his pious daughter, dragged to the dungeon of the Inquisition, and there visited by the future secretary of the English Commonwealth. In his own great maxim, that "we can not teach truth to another, we can only help him to find it," is contained the germ of all true wisdom, and the foundation of those future inductions which were to underlie a new age and revolutionize the world.