LIFE AND WORKS OF KEPLER. 99 



tributeilin a spirit of loyalty to liis old master INFoestliii. Altliougli en- 

 tirely misled as to au elementary law of refraction, Kepler has here cal- 

 culated a table of astronomical refractions, which from the zenith to 7(P 

 does not differ more than 9" from that adopted at present, but in ap- 

 proaching the horizon the deviations become more considerable. We 

 recognize in this book the hand of no ordinary artiticer; its i^ernsal is 

 embarrassed by few ditiicnlties, and although in its doctrines tares be 

 mingled in abundance with the good graiu, the student who wishes to 

 ])rove all things for liimself would still find much to repay his labor. 

 Descartes, who cites it with honor in his Dioptrics^ expressly acknowl- 

 edged the obligations wliicli he owed to it. 



But, while striving to attain the objects which he had proposed to 

 himself, Kepler, as astronomer to the emi)eror, conld not properly re- 

 main inattentive to the events which were taking place in the skies. 

 He wrote, in IGOC, a long dissertation on a star which had appeared in 

 the constellation of the Serpent, and which, after having shone Avith a 

 brilliancy greater than that of Jupiter, disappeared as mysteriously as 

 it had come. This phenomenon, strange but not unexampled, caused 

 a great sensation. " If I should be asked," said Kepler, " wlmt will 

 come to pass ; what it is that this apparition forebodes ? I shall an- 

 swer without hesitation : First of all a flood of writings, published by 

 numerous authors, and much labor for the printers. If I should be ac- 

 cused of having in my dissertation passed too slightingly over the the- 

 ological and political consequences, I shall reply that my charge imposes 

 on me the obligation of promoting astronomy to the best of my ability, 

 but not of fultilling the office of public prophet. I am glad of it ; if I 

 had to speak freely of all that passes in Europe and in the church, I 

 should be much in danger of giving offense to all the world, for as Hor- 

 ace says, 



" JJiacos intra muros i)eccatur el exfra."^ 



One would scarcely suppose on reading these lines that they were 

 written in 160G! 



He proceeds to inquire whence this star could have sprung and of what 

 matter it was formed ; but he does not succeed in solving the question, 

 and concludes only that the blind force of atoms has nothing to do with 

 it. Of this opinion also was his wife Barbara; Kepler tells us so in one 

 of those personal digressions in which ho sometimes indulges, aud 

 which are so vivid and sprightly that in reading them we almost seem 

 to hear and see him, and at the same time are so naturally introduced 

 that we feel no surprise at finding them mixed up with the serious 

 thoughts on which he is intent. " Yesterday," he says, " fatigued with 

 writing and troubled in mind with meditations upon atoms, I was called 

 to dinner, and my wife placed a salad on the table. Do you think, said 

 I to her, that if tin-plates, lettuce leaves, grains of salt, drops of oil and 

 vinegar, and fragments of hard-boiled eggs had been floating in space 

 ever since the creation, in every direction and without order, chance 

 could have brought them together to-day to form a salad? — Not so good 

 a one, I am certain, replied my fair spouse, nor so well made as this 

 cue is." 



The treatise on the new star, which contains thirty chapters, leaves 

 the reader as ignorant as the author himself was aud as we to-day are 

 of the nature and causes of the catastrophe which, from the presumed 



* Trojans aud Greeks, seditious, base, unjust, 

 Oifend alike in violence and lust. — Fkaxcis's translation. 



