100 LIFE AND WORKS OP KEPLER. 



distance of the stars, must have been accomplished iu the heavens 

 and have troubled the systems of the cosmos many ages before the 

 observations of Kepler. 



After nine years of efforts i^rosecuted with an intense application of 

 mind which sometimes, as he tells us, had tormented him almost to 

 madness, diu nos torscrat ad insaniam, Kepler succeeded in exactly 

 representing the movement of Mars by two of the laws which have since 

 been recognized as applicable to the other planets, and which have im- 

 mortalized his name. His work is entitled : Astronomia nova, seu Physica 

 ccclestis, &c. (The new astronomy, or celestial physics, founded on the 

 study of the movement of Mars, deduced from the observations of Tycho- 

 Bralie.) The preface, addressed to the Emperor Rudolph, furnishes a 

 curious example of the si^irit of the epoch, even more than of the genius 

 of Kepler : 



" I bring to yonr Majesty," he says, ^' a noble prisoner, a trophy of an 

 arduous and long doul3tful war, prosecuted under your ausi)ices. Nor 

 do I fear that he will refuse or scorn the name of captive, since it is not 

 the first time that he has borne it ; long ago, as we are informed, the ter- 

 rible god of war fell ingloriously into the toils spread for him by Vulcan. 

 Yet, until now, none had more completely triumphed over all human 

 stratagems ; it was iu vain that the astronomers prepared every thing 

 for the struggle; in vain that they brought all their resources into action 

 and marshalled all their forces. Mars, mocking at their attempts, dis- 

 concerted their i)lans and baffled their hopes. Withdrawn in an im- 

 penetrable secrecy, he succeeded in veiling his skillful evolutions from 

 hostile observation. The ancients complained of this deceptive strategy 

 more than once, and that indefatigable explorer of the mysteries of 

 imture, Pliny, pronounced Mars inscrutable to human eye. 



"For myself, I ought first of all to extol the activity and pertinacity of 

 the valiant chieftain Tycho-Brahe, who, under the auspices of the Dan- 

 ish sovereigns, Frederick and Christian, studied every night for twenty 

 years the procedures of the enemy, iu order to discover the jilans of the 

 campaign and the secret of his movements. The observations be- 

 queathed to me by my predecessor have aided me iu dispelling that 

 vague and indefinite apprehension which is at first felt iu the presence 

 of Pj mysterious foe. 



" During the uncertainties of the contest how many disasters have 

 desolated our camp ! The loss of an illustrious chieftain, sedition and 

 desertion among the troops, contagious maladies, all contributed to aug- 

 ment our distress. Domestic solace and suffering alike interfered with 

 business ; a new enemy, as I have reported iu my book on the late evan- 

 escent star, precipitated himself on the rear of our army ; the veterans 

 withdrew, the new recruits were untrained, and, worst of all, provisions 

 were exhausted. Finally, however, the enemy became reconciled to 

 peace, and by the mediation of his mother, Nature, sent me the avowal 

 of his defeat. He surrendered on his parole, and Arithmetic and Geo- 

 metry escorted him into our camj). From that time he has shown that 

 he can be entirely trusted, and, content with his lot, asks but one fiivor 

 of your majesty. All his family is in the sky ; Jupiter is his father, 

 Saturn his grandsire. Mercury his brother, and Venus his bosom fiiend 

 and sister. Accustomed to their august society he is ardently desirous of 

 recovering it, and would wish that like himself they were all received iuto 

 your majesty's common hospitalitj\ To that end it is important to profit 

 by our success and to pursue the war with vigor ; its hazards are at an 

 end, since Mars is in our power. But I entreat your majesty to remem- 

 ber that money constitutes the nerves of war, and to be pleased to order 



