Tycho and Kepler (33 page)

Kepler had several advantages working in his favor. In addition to his position at the school, he was the district mathematician. Because this was a neutral office,
neither Protestant nor Catholic, it provided a valuable argument for allowing Kepler to remain in Graz. Kepler also had friends in high places who could make this argument for him. He had been carrying on a lively correspondence about scientific questions with the Bavarian chancellor Hans Georg Herwart von Hohenburg. Although the chancellor was a devout Catholic, he remained a helpful and sympathetic
friend in the present crisis. Kepler had other influential contacts as well and knew that Ferdinand himself
enjoyed
hearing about his scientific discoveries. When Kepler petitioned for permission to return to the city, his petition was granted. For the time being, he was safe.

Protestants still in Graz temporarily found ways to circumvent the ban on Protestant worship by attending services
at nearby country estates whose Protestant clergy had not been sent away. There was soon an end to that as well, and new ordinances required Protestants to baptize their children as Catholics and marry only in Catholic ceremonies. “Heretical” books were banned, including Luther’s translation of the Bible. Searches took place throughout the city, and ten thousand volumes were burned.

Kepler
had no teaching duties now that the school was closed. He spent his days immersed in new thoughts about the harmony of the heavens. Von Hohenburg loaned him books he could not find in Graz, but Kepler did more than read. As he put it, “He who distinguishes himself
¹⁶
by intellectual agility has no inclination to concern himself much with the reading of the works of others. He does not want to lose
any time.” He was beginning the speculation that would result in his book
Harmonice Mundi
twenty years later, and also keeping his eye out for a new job.

Thus it was that in the early autumn of 1598, Kepler, like Tycho, was seeking employment. He was making the best of a far less impressive network than Tycho’s. An appointment at the University of Tübingen seemed the obvious solution, but
Kepler’s inquiry there aroused no interest at all. Meanwhile, the letter Tycho had written in April, reacting to Kepler’s letter and book and praise of Ursus, and a letter from Mästlin concerning the same, were floating about in European mail limbo. Kepler still had not learned that Tycho had actually penned a vague invitation to join him. There was no easy way Kepler could have acted on that invitation,
even had he known of it. Tycho was far away, and the offer was not concrete enough to encourage Kepler to make such a journey. He could only go on
yearning
in vain for a glimpse of Tycho’s superior observations of the heavens.

T
YCHO
, from his Wandsburg palace, continued to play his cards brilliantly during that summer and autumn of 1598,
showing no signs of having lost his touch as a courtier: Emperor Rudolph’s three most powerful advisers—his personal physician Hagecius, his vice chancellor Rudolph von Coraduz, and Johannes Barvitius—were all working in Tycho’s cause. Rudolph heard from this undisputed inner circle at his court—as well as from his gem artist and astrologer Caspar Lehmann—that princes, archbishops, and scholars all
over Europe were poring over splendid illustrations in books Tycho Brahe had sent them as gifts. No book had arrived for Rudolph, but the reason for this omission was in the air at court: Tycho wished to present it to the emperor in person. Soon Lehmann reported that Rudolph could scarcely contain his eagerness to meet Tycho and would offer him a sumptuous dwelling. In mid-August Tycho heard from
his other contacts that the time was ripe for him to come to Prague: The emperor was indeed prepared to extend his patronage.

Even while Tycho’s fortunes were improving, Ursus had never been far from his mind. Longomontanus, having just completed his master’s degree at Rostock, was back for a time that summer, mainly to discuss the Ursus problem. It gave much cause for celebration when the
news arrived from Lehmann that the emperor had lost all confidence in the trustworthiness and abilities of his present imperial mathematician.

By September 29 Tycho, his family, and his retainers had packed everything up for another move, and the great household was ready to depart from Wandsburg. Instruments, library, furniture were on the wagons again, lashed down and protected from the
weather. The carriages were brought, and the horses harnessed. Footmen helped Kirsten and the children into their carriages. The armed escorts
mounted
. Tycho’s carriage with its six horses led the way, and the long train of animals, wagons, carriages, and outriders fell into line, rattled back across the drawbridge of Wandsburg, and turned south along the Elbe River, in the direction of Prague.

This time, the journey was more like a royal progress than moving house. There had been time to prepare, have proper clothing made for himself and his wife and children, inform noble and scholarly friends and kinsmen that he would be calling on them along the way. By October 5 the convoy reached Harburg, not far from Hamburg, where Tycho elicited another letter of reference, this one from the
aged Duke Otto II of Braunschweig-Lüneburg to the imperial high steward at the court.

When they reached Magdeburg, Tycho took advantage of the presence of an old friend and correspondent, Rector Georg Rollenhagen, to further his campaign to crush Ursus. It was from Rollenhagen that Tycho had first learned about Ursus’s earlier book,
Fundaments of Astronomy
, in which Ursus claimed the Tychonic
system as his own, and Rollenhagen had put Tycho in touch with Lehmann, his brother, at the imperial court. Tycho now took the opportunity to question Rollenhagen in detail about an incident in 1586 when Ursus, asked to explain his planetary system, had proved mysteriously incapable of doing so—further evidence that he had not invented it himself. Rollenhagen supported Tycho’s decision that a
nobleman should not sully himself by disputing directly with a pig farmer—no matter how high that pig farmer had risen—but should allow lawyers, clients, and friends to take care of this matter for him.

Tycho had also summoned Erik Lange to Magdeburg. After making it clear he would not cooperate with Lange’s “appalling plan” to accompany him to Prague to interest the emperor in underwriting
his experiments for turning base metals into gold, Tycho compelled Lange to testify before a notary about Ursus’s behavior those many years ago at Uraniborg. By this time Tycho must have all but given up hoping that Kepler would ever respond to his letter of the previous
April
, which had included a request for a document Tycho could use against Ursus.

The stop in Magdeburg gave Tycho time
to consider whether it might not work against his interests to arrive in Prague accompanied by family and twenty-two wagons, as though he were a refugee casting himself on Rudolph’s mercy or, on the other hand, an overconfident man taking Rudolph’s munificence too much for granted. A lack of total commitment to the move might even help in negotiations having to do with how generous the emperor’s patronage
would be. If it seemed advisable to retreat for a time, Tycho would have a good excuse, to return to his family and work. Perhaps most compelling of all, the journey would go much more quickly than it could with all the wagons, and winter was not far away. Tycho reverted to an earlier plan of taking a small company of assistants and only a few of his instruments with him. He left the other
instruments and much of the baggage train in Magdeburg, and Kirsten and their daughters and servants, escorted by Longomontanus, returned to Wandsburg. Tycho continued the journey with his two sons and a few other retainers, including the superbly effective Tengnagel.

They still did not ride posthaste to Prague, but stayed a month in Dresden while waiting for surer confirmation that a suitable
welcome awaited Tycho. Word came that the emperor was delighted to hear he was on his way to Prague, but that an epidemic was raging in the area, winter was closing in, and the court had temporarily moved from the city. Tycho was advised to wait until spring. He decided to winter in Wittenberg, Martin Luther’s old city.

fn1
It was this catalog—not a better one—that Kepler later used.

15

C
ONTACT

November 1598–June 1599

IN LATE NOVEMBER
or early December 1598, Kepler opened a letter from
¹
an extremely agitated Mästlin. This was the first Kepler knew that he had made a fool of himself with potentially disastrous results for his career, and Mästlin’s letter did not even make it clear precisely what the situation was, except that it was bad.

The reply Tycho had
written Kepler
²
shortly after receiving the two books and Kepler’s letter at Wandsburg never reached Kepler. But Tycho had sent Mästlin a copy
³
, and Mästlin, reading that in June and assuming that Kepler had the original, had immediately written to Kepler, reprimanding him for praising Ursus when Mästlin himself had warned him that the man’s work was worthless. Then Mästlin’s reprimand had also
gone astray and taken five months to reach Kepler.

Kepler asked Mästlin to send him a copy of Tycho’s April letter, and finally had that in his hands in February. It was not nearly so awful as he had been expecting. It was even rather polite and complimentary. Although Tycho expressed some reservations about the polyhedral theory, he wrote that he found it extremely ingenious and hoped Kepler
would try applying it to the Tychonic system. He went
on
to comment, however, that Copernicus’s measurements for the planetary distances were not accurate enough for the purposes to which Kepler was putting them, and Kepler might want to use instead the more accurate observations that he, Tycho, had made.

Tycho’s hook dangled enticingly before Kepler’s eyes. He was so overjoyed that he penned
in the margin, “One can see his high opinion of my method.”

There was, however, more to Tycho’s letter, a lengthy postscript containing what was, under the circumstances, a remarkably restrained complaint about Kepler’s unctuous praise of Ursus. Tycho wrote that he could not imagine that Kepler had been aware that Ursus would use his letter in his “defamatory and criminal publication.” He
suggested that Kepler might give him a statement of his opinion of Ursus’s behavior, which document Tycho could use in legal proceedings against Ursus.

Tycho had given Kepler a glimpse of the reward that might be his and had named the price of his forgiveness. Kepler also knew that in a separate letter to Mästlin, Tycho had criticized
Mysterium
much more severely and complained about the letter
reprinted in Ursus’s book. Tycho surely anticipated that Kepler’s influential mentor would communicate with his errant pupil, and he was treading a delicate line between flattery and encouragement on the one hand and criticism and reprimand on the other.

Even before he had read the copy of Tycho’s actual words to him, Kepler had taken Tycho’s bait on the strength of Mästlin’s correspondence.
He had also not seen Ursus’s book and did not know whether Ursus had quoted him correctly or distorted what he had written. Kepler could not even remember precisely what he
had
written, nor did he know which letter Ursus had quoted, for there had been more than one, and he had not kept copies. In a blind panic about the appalling situation he had got himself into with one of the great men of the
age, who actually was inclined to
like
his work, Kepler threw
himself
at Tycho’s feet in a long reply, written with characteristic eloquence and dramatic flair:

Why does [Ursus]
⁴
set such value on my flatteries? . . . If he were a man he would despise them, if he were wise he would not display them in the market place. The nobody, that I was then, searched for a famous man who would praise
my new discovery. I begged him for a gift and behold, it was he who extorted a gift from the beggar. . . . My spirit was soaring and melting away with joy over the discovery I had just made. If, in the selfish desire to flatter him I blurted out words which exceeded my opinion of him, this is to be explained by the impulsiveness of youth.

Tycho’s response this time
⁵
was gracious, but he kept
Kepler in his place by saying that he had not required such an elaborate apology.