LIFE AND WORKS OF KEPLER. 97 



■without cruelty, Ferdinand succeeded in suppressing the Protestant wor- 

 ship in Styria. 



However this may be, Kepler, thus deprived of the means of subsist- 

 ence and banished from Styria, where numerous friends had surrounded 

 him, remained unshaken in liis faith. The Counsellor Herwart in vain 

 l^rojiosed to him terms of accommodation ; his integrity could not be 

 made to bend. Kepler, so ingenious in his researches, was by no means 

 so in paltering with his conscience. Unable to yield his reason to the 

 Catholic creed, he obstinately refused it his homage. The reasons on 

 which he based his resolution, equally remote from the weakness which 

 bends to persecution and the arrogance which braves it, are impressed 

 with a calm and gentle dignity : " I am a Christian," he writes to Her- 

 wart, "attached to the confession of Augsburg by a thorough examina- 

 tion of the doctrine, not less than by the instruction of my parents. 

 Tliat is my faith ; I have already suffered for it, and I know not the art 

 of dissembling. Eeligion is for me a serious atfair, which I cannot treat 

 with levity." And he continued, without losing heart, to find a refuge 

 in science, devoting to it his hours of labor, his studious watchings, the 

 ardent yearnings of his enthusiastic intellect. But this could not wholly 

 preclude the bitter thoughts of exile and of poverty; if little concerned 

 for himself, he could not help feeling how nearly those afflictions touched 

 those who were dear to him. "I entreat you," he writes to Moestlin, "if 

 there is a place vacant at Tiibingen, contrive to obtain it for me; let me 

 know," he adds, " the price of bread, of wine, and the necessaries of life, 

 for my wife has not been accustomed to a diet of beans." It was under 

 these trying circumstances that he received from the celebrated Tycho- 

 Brahe, who had become acquainted with his adversity, a i)roposition to 

 unite w ith him in the astronomical labors with which he had been charged 

 by the Emj^eror Eudolph. Kepler did not hesitate, and repaired with 

 his family to Prague. 



Nothing could have been more fortunate for astronomy than the union 

 of Kepler with such a man, whose researches, less brilliant perhaps than 

 his own, are distinguished by a laborious precision, which no previous 

 astronomer had ever carried to the same degree of perfection. Kepler, 

 himself, seems to have foreseen all its advantages when, speaking of the 

 observations accumulated by Tycho, he wrote the year previous to 

 Mcestlin : " T3'clio is loaded with riches which, like most of the rich, he 

 makes no use of." He had i:)racticed observation, in effect, for thirty- 

 five years, without any preconceived idea, while keeping an exact and 

 minute register of the phenomena of the heavens. These accumulated 

 results, without directly disclosing the truth, were admirably calculated 

 to preserve Kepler from error by furnishing a solid point of support to 

 the boldness of his inventive genius, and as a limit established in ad- 

 vance to prohibit its excesses. Having soon afterwards become, by the 

 death of Tycho, possessor of the precious materials destined to fertilize 

 his ideas, he was not slow in perceiving that under the confusion of 

 those elements, which he might justly compare to the scattered leaves 

 of the Sibyl, was concealed an eternal and immutable order, and he 

 sought it duringnine years with the unwearied devotion which triumphs 

 over discouragement, and with the energy which assures success. 



But with a view to proceeding in order, he first directed his attention 

 to the elimination of a cause of error already indicated b}- Tycho, and 

 one with which all the astronomical observations are infected : he stud- 

 ied the laws of refraction. 



Hipparchus relates that twice in the same day he had observed the 

 sun in the equator, and consequently two equinoxes. From this Ptolemy 

 7 s 



