weight, the scientific construction of the system of Copernicus, the pendulum, the improvement of many scientific instruments, the invention of the hydrostatic balance, the thermometer, proportional compasses, and, above all, the telescope. He discovered the satellites of Jupiter, the phases of Venus, the mountains of the moon, the spots and the rotation of the sun. Science, which had consisted for centuries only of scholastic subtleties and barren dialectics, he established on an experimental basis. In his works he unites delicacy and purity with vivacity of style. Among the scholars of Galileo, who most efficaciously contributed to the progress of science, may be mentioned Torricelli (1608-1647), the inventor of the barometer, an elegant and profound writer; Borelli (1608-1679), the founder of animal mechanics, or the science of the movements of animals, distinguished for his works on astronomy, mathematics, anatomy, and natural philosophy; Cassini (1625-1712), a celebrated astronomer, to whom France is indebted for its meridian; Cavalieri (1598-1648), distinguished for his works on geometry, which paved the way to the discovery of the infinitesimal calculus. In the scientific department of the earlier part of this period may also be mentioned Tartaglia (d. 1657) and Cardano (1501-1576), celebrated for their researches on algebra and geometry; Vignola (1507-1573) and Palladio (1518-1580), whose works on architecture are still held in high estimation, as well as the work of Marchi (fl. 1550) on military construction. Later, Redi (1626-1697) distinguished himself as a natural philosopher, a physician and elegant writer, both in prose and verse, and Malpighi (1628-1694) and Bellini (1643-1704) were anatomists of high repute. Scamozzi (1550-1616) emulated the glory formerly won by Palladio in architecture, and Montecuccoli (1608-1681), a great general of the age, ably illustrated the art of strategy. The sixteenth century abounds in philosophers who, abandoning the doctrines of Plato, which had been in great favor in the fifteenth, adopted those of Aristotle. Some, however, dared to throw off the yoke of philosophical authority, and to walk in new paths of speculation. Patrizi (1529-1597) was one of the first who undertook to examine for himself the phenomena of nature, and to attack the authority of Aristotle. Telesio (1509-1588), a friend of Patrizi, joined him in the work of overthrowing the Peripatetic idols; but neither of them dared to renounce entirely the authority of antiquity. The glory of having claimed absolute freedom in philosophical speculation belongs to Cardano, already mentioned, to Campanella (1568-1639), who for the boldness of his opinions was put to the torture and spent thirty years in prison, and to Giordano Bruno (1550- 1600), a sublime thinker and a bold champion of freedom, who was burned at the stake.