*SCHNEEMANN (P. S. J.): “Galileo Galilei und der Römische Stuhl.” Stimmen aus Maria Laach. Kath. Blättern. Nos. 2, 3, 4, Feb. Mar. April, 1878. SNELL (Dr. Carl): “Ueber Galilei als Begründer der mechanischen Physik und über die Methode derselben.” Jena, 1864. TARGIONI TOZZETTI: “Notizie degli aggrandimenti delle scienze fisiche in Toscana.” Firenze, 1780. (Contains in Vol. ii.: “Vita di Galileo scritta da Nic. Gherardini.”) VENTURI (Cav. Giambattista): “Memorie e lettere inedite finora o disperse di Galileo Galilei.” Modena, 1818-1821. VIVIANI: “Raconto istorico della vita di Galileo Galilei.” (Enthalten im XV. Bande der Opere di Galileo Galilei. Prima edizione completa. Firenze, 1856.) VOSEN (Dr. Christian Hermann): “Galileo Galilei und die Römische Berurtheilung des Copernicanischen Systems.” Broschürenverein Nr. 5. Frankfurt am M. 1865. WOHLWILL (Dr. Emil): “Der Inquisitionsprocess des Galileo Galilei. Eine Prüfung seiner rechtlichen Grundlage nach den Acten der Römischen Inquisition.” Berlin, 1870. *“Ist Galilei gefoltert worden? Eine kritische Studie.” Leipzig, 1877. “Zum Inquisitionsprocesz des Galileo Galilei.” _Zeitschrift für Mathematik und Physik._ 17. Jahrgang. 2. Heft. 1872. *WOLYNSKI (Dott. Arturio): “Lettere inedite a Galileo Galilei.” Firenze, 1872. *“Relazione di Galileo Galilei colla Polonia esposte secondo i documenti per la maggior parte non pubblicati.” Firenze, 1873. “La Diplomazia Toscana e Galileo Galilei.” Firenze, 1874. PART I. _GALILEO’S EARLY YEARS, HIS IMPORTANT DISCOVERIES, AND FIRST CONFLICT WITH THE ROMAN CURIA._ CHAPTER I. _EARLY YEARS AND FIRST DISCOVERIES._ Birth at Pisa.—Parentage.—His Father’s Writings on Music.—Galileo destined to be a Cloth Merchant.—Goes to the Convent of Vallombrosa.—Begins to study Medicine.—Goes to the University of Pisa.—Discovery of the Isochronism of the Pendulum.—Stolen Lessons in Mathematics.—His Hydrostatic Scales.—Professorship at Pisa.—Poor Pay.—The Laws of Motion.—John de’ Medici.—Leaves Pisa.—Professorship at Padua.—Writes various Treatises.—The Thermoscope.—Letter to Kepler.—The Copernican System.—“De Revolutionibus Orbium Cœlestium.” The same memorable day is marked by the setting of one of the most brilliant stars in the firmament of art and the rising of another in the sphere of science, which was to enlighten the world with beams of equal splendour. On the 18th February, 1564, Michael Angelo Buonarotti closed his eyes at Rome, and Galileo Galilei first saw the light at Pisa.