Page:The Gradual Acceptance of the Copernican Theory of the Universe.djvu/63

 they say, into the bottom of this business … and bring myself to a certainty in this subject."

Galileo's brilliant work in mechanics and his great popularity—for his lectures were thronged—combined with his skilled and witty attacks upon the accepted scientific ideas of the age, embittered and antagonized many who were both conservative and jealous. The Jesuits particularly resented his influence and power, for they claimed the leadership in the educational world and were jealous of intruders. Furthermore, they were bound by the decree of the fiftieth General Congregation of their society in 1593 to defend Aristotle, a decree strictly enforced. While a few of the Jesuits were friendly disposed to Galileo at first, the controversies in which he and they became involved and their bitter attacks upon him made him feel by 1633 that they were among his chief enemies.

Early in 1609, Galileo heard a rumor of a spy-glass having been made in Flanders, and proceeded to work one out for himself according to the laws of perspective. The fifth telescope that he made magnified thirty diameters, and it was with such instruments of his own manufacture that he made in the next three years his famous discoveries: Jupiter's four satellites (which he named the Medicean Planets), Saturn's "tripartite" character (the rings were not recognized as such for several decades thereafter), the stars of the Milky Way, the crescent form of Venus, the mountains of the moon, many more fixed stars, and the spots on the sun. Popular interest waxed with each new discovery and from all sides came requests for telescopes; yet there were those who absolutely refused even to look through a telescope lest they be compelled to admit Aristotle was mistaken, and others claimed that Jupiter's moons were merely defects in the instrument. The formal announcement of the first of these discoveries was made in the Sidereus Nuncius (1610), a book that aroused no little opposition. Kepler, however, had it reprinted at once in Prague with a long appreciative preface of his own.

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