The treatment which Galileo received at the hands of the ecclesiastics of his day is well known. This father of experimental philosophy was born at Pisa in 1564, and at the age of twenty-four years, through the favour of the Medicis, was elected Professor of Mathematics at the University of the same town. Resigning his chair in 1592, he became professor at Padua, and then at Florence. He startled the world by the publication of his first book, _Sidereus Nuntius_, in which he disclosed his important astronomical discoveries, amongst others the satellites of Jupiter and the spots on the sun. This directed the attention of the Inquisition to his labours, but in 1632 he published his immortal work _Dialogo sopra i due Massimi Sistemi del monda, Tolemaico et Copernicano_ (Florence), which was the cause of his undoing. In this book he defended the opinion of Copernicus concerning the motion of the earth round the sun, which was supposed by the theologians of the day to be an opinion opposed to the teaching of Holy Scripture and subversive of all truth. The work was brought before the Inquisition at Rome, and condemned by the order of Pope Urban VIII. Galileo was commanded to renounce his theory, but this he refused to do, and was cast into prison. "Are these then my judges?" he exclaimed when he was returning from the presence of the Inquisitors, whose ignorance astonished him. There he remained for five long years; until at length, wearied by his confinement, the squalor of the prison, and by his increasing years, he consented to recant his "heresy," and regained his liberty. The old man lost his sight at seventy-four years of age, and died four years later in 1642. In addition to the work which caused him so great misfortunes he published _Discorso e Demonstr. interna alle due nuove Scienze, Delia Scienza Meccanica (1649), Tractato della Sfera (1655)_; and the telescope, the isochronism of the vibrations of the pendulum, the hydrostatic balance, the thermometer, were all invented by this great leader of astronomical and scientific discoverers. Many other discoveries might have been added to these, had not his widow submitted the sage's MSS. to her confessor, who ruthlessly destroyed all that he considered unfit for publication. Possibly he was not the best judge of such matters!