Uytl COSMOl. 



tion of the apparent revolution of the heaven of the fixed 

 stars by the diurnal rotation of the earth round its axis; 

 und by its annual movement round the sun he had afforded 

 an equally perfect solution of the most striking movements 

 of the planets (their stationary conditions and their retro- 

 gressions), and thus given the true reason of the so-called 

 second inequality of the planets. The first inequality, or 

 the unequal movement of the planets in their orbits, he left 

 unexplained. True to the ancient Pythagorean principle 

 of the perfectibility inherent in circular movements, Co- 

 pernicus thought that he required for his structure of the 

 universe some of the epicycles of Apollonius of Perga, besides 

 the eccentric circles having a vacuum in their centre. How- 

 ever bold was the path adventured on, the human mind could 

 not at once emancipate itself from all earlier views. 



The equal distance at which the stars remained, while the 

 whole vault of heaven seemed to move from east to west, had 

 led to the idea of a firmament and a solid crystal sphere, in 

 which Anaximenes (who was probably not much later than 

 Pythagoras), had conjectured that the stars were ri vetted like 

 nails.* Gerninus of Rhodes, the cotemporary of Cicero, 

 doubted whether the constellations lay in one uniform plane ; 



mixing, inability of shedding tears, and of sorcery. The suspicion was 

 increased from the circumstance that her own son, the wicked Christo- 

 pher Kepler, a worker in tin, was her accuser ; and that she had been 

 brought up by an aunt, who was burnt at Weil as a witch. See an ex- 

 ceedingly interesting work, but little known in foreign countries, drawn 

 from newly-discovered manuscripts by Baron von Breitschwert, entitled 

 "Johann Keppler's Leben und Wirken" 1831, s. 12, 97-147, and 196. 

 According to this work, Kepler, who in German letters always signed 

 his name Keppler, was not born on the 21st December, 1571, in the 

 Imperial town of Weil, as is usually supposed, but on the 27th of Decem- 

 ber, 1571, in the village of Magstadt, in Wurtemberg. It is uncertain 

 whether Copernicus was born on the 19th of January, 1472, or on thg 

 19th February, 1473, as Mostlin asserts, or (according to Czynski) on 

 the 12th February of the same year. The year of Columbus' birth was 

 long undetermined within nineteen years. Ramusio places it in 1430, 

 Bernaldez, the friend of the discoverer, in 1436, and the celebrated histo- 

 rian Munoz, in 1446. 



* Plat., Deplete. Philos., ii. 14; Aristot. M eteorol. xi. 8; De Ccdo.ii. 

 8. On the theory of spheres generally, and on the retrograding spheres 

 of Aristotle in particular, see Ideler's Vorlevung iiber Eudoxus, 1828, 

 B. 49-60. 



