ixNM^KrnrFRi^ mji iiiNir*! CO c >KU\ ic»n \f» v Mftimioriiu'.t n ( < nice r O Mai mi v* Nf amtouvs LHrJUULI m nc. xwii § m m > z a H m3C jftaUISp m en C H theJESU CD BY M.W. BURKE - GAFFNEY ST. IGNATIUS LIBRARY »**,.* ^ » 980 T- PARK AVENUE / »naT,„, oh NEW YORK CITY 28 "«w Vowk Date Loaned ©23 IM ^0*0v&*0v&A&*&*&*&H&*&*&*&K&r&*&*.&>»&*'&*&*,O'*'&*-0*&*&* Kepler and the Jesuits ^^<^W^Jl^X^lt^>C^lC^X^X^K^>t^X^5<^X^X^K^X^X^X^X^X^l<^)t^l<^> "My thoughts are with the Dead; with them 1 live in long-past years, Their virtues love, their faults condemn, Partake their hopes and fears, And from their lessons seek and find Instruction with a humble mind." — SOUTHEY. M. W. BURKE-GAFFNEY, S.J. 'I measured the skies." Johann Kepler THE BRUCE PUBLISHING COMPANY MILWAUKEE Imprimi potest: T. J. Mullai-ly, S.J. Nihil obstat: H. B. Rjes, Censor librorum Imprimatur: + Moyses E. Kiley. Archiepiscopus Milwaukiensis Die 11 Aprilis. 1944 CONTENTS Page Chapte f 1 I Introducing Kepler II The Imperial Mathematician 15 III . 26 IV V . 60 VI Sunspots ..... • 71 VII Mercury in the Sun . 8s 9i WAR FORMAT VIII Heliocentric Hypothesis • This book is produced in complete accord with the Governinem regulations for the conservation of paper and other essential materials. IX X Aids to Astronomy . 117 XI The Last Chapter 129 Bibli Copyright. 1944 The Bruce Publishing Company Indej Printed in the United States of America CHAPTER I INTRODUCING KEPLER Johann Kepler was enjoying a studentship at the University of Tubingen when the Parodies, the Lutheran school at Graz, applied for a teacher of astronomy. Kepler was recommended and elected on the score of his mathematical ability. As he tells us, he had no particular taste for astronomy; but he had little choice. His patrons had recommended him; his penniless father had already deserted a querulous wife, and left creditors behind — beggars cannot choose. At Graz Kepler had not only to lecture in astronomy, but had also to construct an almanac for each year, foretelling future events. He threw himself into the study of astrology, studying it with all the more zest when private prognosticating proved a lucrative practice. To gain experience and guidance, he noted the positions of the planets against the events of his own life, and those of his relatives — to these records we are indebted for the minutiae of his biography. He himself enters the picture at the instant of his birth, of which he gives us the time to the nearest minute: half-past one in the morning of December 27, 1571, at Weil, in Wurttemberg — a premature and sickly son, as, he says, the planets had foretold. He was born in the best-known house in Weil, the residence of the Burgomaster, his paternal grandfather. It was only after Johann's birth that his parents set up house for themselves. The venture was not very successful; they fought like cat and dog. In 1574 Herr Kepler deserted his wife and two sons, to go and fight in Belgium. When Frau Kepler learned where he was, she went to the front herself and fetched him back. They bought a little farm in the village of Leonberg; but after he had been to war, there was no keeping Heinrich Kepler on a KEPLER AND THE JESUITS INTRODUCING KEPLER 3 the farm. In 1576 he was off to Belgium again. This time he and his textbook was the second edition of Mastlin's Epitome got a little more than bargained he had for. On November 4, of Astronomy. Mastlin's book made no mention of Copernicus 1576, Spanish fury was let loose in Antwerp; the town was or his theory. But Kepler tells us that Mastlin explained the sacked; the German mercenaries, under Count Oberstein, were Copernican theory to him, and that he himself admired it. His completely routed and dispersed; and Kepler's father was home admiration sowed a seed which was to be the source of much again. This time he bought a tavern in the village of Elmen- fruit after he left Tubingen. However, he did not leave im- digen, and Johann started to school. He went to a school mediately after receiving his master's degree; but was kept on, where German was the medium of instruction, and not Latin, carried by funds supplied from the foundation of the Uni- as at the next schools he was to attend. He recalls having heard versity. He was waiting and hoping to be promoted to Witten- much talk of the comet of this year, 1577, and of having been berg, to proceed to his doctorate in theology. Meanwhile, he brought up to a high place by his mother to see it. The comet wrote a paper on the motion of the earth, and how it might of 1577 was the one which Tycho Brahe proved to be more be reconciled with Sacred Scripture. Then, in 1594, Graz, in distant than the moon. By comparing observations made of it the Province of Styria, applied to Tubingen for a scholar from Uraniburg and from Prague (which are about 400 miles capable of teaching astronomy. The Senate of Tubingen sug- apart), Brahe showed that it seemed to occupy the same position gested Kepler; the Rector advised him to accept. among the stars from wherever seen. The background of the Graz is pretty. It is on the banks of the Mur (the Napoleonic moon, on the other hand, varies with the point of view. Eleven French called it la ville des Graces sur la riviere de I Amour). years later, Brahe published his facts which exploded the notion Lutheran doctrine found its way to Graz as early as 1530, and that comets were sublunary phenomena. in 1540, a Lutheran school, the Parodies, was opened. The After three years at the school at Elmendigen, Kepler had Archduke Charles recognized the teacher of astronomy at the to stay at home to help his parents. He worked in the fields at Parodies as Provincial Mathematician. When Kepler went to the tender age of nine, and never forgot how hard it was. Graz, there was no Archduke in residence. Charles had died One day he was called to look at an eclipse of the sun, and in 1590, when his eldest son and heir, Ferdinand, was twelve was struck by the redness around the moon as it blotted out years of age. The young Archduke did not take over the gov- the sunlight. It must have been, he later calculated, the eclipse ernment of Styria until 1590. Until he took over, Kepler's of January 31, 1580. Lutheranism was no impediment to his being Provincial Three years later his father lost all he possessed by a forfeited Mathematician in a Catholic province. security; and Johann was free to return to school. Moreover, Kepler went down to Graz all but convinced of the truth as the son of a pauper he was a deserving object of charity. of the Copernican theory. The only difficulties he had in The Monastery School at Adelberg opened its doors to him admitting it were other than mathematical. He could under- on October 16, 1584. After two years he was received into the stand the earth being the center of the universe, as Ptolemy Protestant Seminary of Maulbroon. There, in 1589, he passed would have it. All things were created for men who live on a brilliant bachelor's examination, and was sent to the Uni- the earth. Why then should the sun be the center of our versity of Tubingen to master in philosophy. As part of the system? He thought up this answer for himself: usual course, Kepler had to study astronomy. Though inter- Of all the bodies in the universe the most excellent is the ested, he did not then suspect that astronomy was to be sun, his whose whole essence is nothing else but the purest light. life's work. His professor I of astronomy was Michael Mastlin; han it there is no greater star; singly and alone it is the 4 KEPLER AND THE JESUITS INTRODUCING KEPLER 5 producer, conserver, and warmer of all things. It is a fountain hedron in which was inscribed a sphere, a great circle of which of light, rich in fruitful heat, most fair, limpid, and pure to the circle of Mercury. Near the center of Mercury's sphere the sight. It is was the source of vision and the portrayer of all sun. Since, according to Copernicus, the colours, though itself devoid of colour. was the immobile circled about a point on their circles, it was necessary There planets remained other difficulties. Why were there five planets to give each sphere a thickness, to afford room for the planet's besides the earth? Why not more or less? And why had the peregrinations. A model of the solar system designed according all-wise Creator placed them as He did? For their distances to Kepler's plan would be very close to a true-to-scale model. Its from the sun, as given by Copernicus, there seemed to be slight deviations from the proportions of Copernicus' system, neither rhyme nor reason. Taking the distance of Mercury Kepler attributed to errors in observations which Copernicus as unity, their mean distances were proportioned as follows: used for his calculations. Mercury ,.00 It was to Mastlin that Kepler broke the news of his discovery, Venus 1.87 and wrote of his desire to publish.