Tycho and Kepler (24 page)

In the spring of 1591 Tycho’s concentration on astronomy suffered serious disruption from an embroilment with a gentleman tenant, Rasmus Pedersen,
¹¹
who lived on a small manor in Zealand
that was part of Tycho’s holdings as a canon of Roskilde Cathedral. The incident began when Pedersen purchased from Tycho a life tenancy of Gundsøgaard, an unprofitable estate with only nine cottages and the ruins of a manor house that had recently burned down. Tycho cannot have charged him very much for this holding, and he was chagrined when Pedersen unexpectedly turned it into a thriving
establishment and rebuilt the house into something large and quite splendid. Pedersen may or may not, in the process, have overstepped his fishing rights and exploited his nine peasant families beyond the usual norm. There were reports that after using their free labor for his building project, he forcibly ejected them from their small plots so that the land could become fields of the manor, then
used their free labor again to build new cottages, and finally obliged them to buy the cottages from him.

Motivated either by concern for the peasants or a desire for the manor house, or both, Tycho attempted to renegotiate the lease and, when Pedersen refused, seized the manor and expelled him without a refund. But Pedersen was persistent: When Tycho ordered the fields at Gundsøgaard to be
plowed and sown, Pedersen had his retainers sow fifty-two and a half bushels of rye right behind Tycho’s sowers. Tycho escalated the conflict. His men seized Pedersen as he was dining and brought him in irons to Hven, while others of Tycho’s agents confiscated Pedersen’s business records and detailed
reports
about the estate. Tycho imprisoned Pedersen at Uraniborg for six weeks until Pedersen
agreed to sign a capitulation. By the spring of 1591, Tycho had brought the matter to court.

A few months later, Tycho’s appeal to the king and the Rigsraad failed when even Tycho’s aristocratic peers, who might have been expected to side with one of their own, were unwilling to view his treatment of Pedersen as normal behavior for a feudal lord. On the way home to Hven, the disgruntled Tycho
voiced his disappointment by composing a Latin epigram complaining of this unfair decision. He did not drop the matter. His next maneuver was to try to link Pedersen with a drowning in a well. That failed. By November 1592 Tycho was holding Pedersen’s brother and a servant as prisoners. There is no record of the result of a second hearing, for which Tycho was allowed to nominate some panelists
to participate in the decision, but two years later he seems to have regained possession of the manor house of Gundsøgaard. There are no further records concerning Pedersen.

Possibly while Tycho was holding Rasmus Pedersen prisoner at Hven, a young man named Georg Ludwig Frobenius arrived. As Frobenius described events in his memoirs,
^fn1
12
he had received his master’s degree from the University
of Wittenberg, worked for a year as a tutor in Saxony, and gone to Denmark, afire to visit Uraniborg and meet Tycho Brahe. He made the initial mistake of seeking entrance after everyone had gone to bed. He might have been forgiven for thinking that since this was an astronomical observatory and it was “a beautiful, clear, and calm night,” the entire household would not be asleep. However, despite
the glowing letters of introduction that Frobenius presented, the porter at the gate turned him away. With the savage barking of the mastiffs kenneled above the gatehouse ringing in his ears, Frobenius walked off to spend the night hungry in a field.

Early the next morning Frobenius tried again at the gate, and Tycho granted him an audience. After conversing with Frobenius and reading his
letters of recommendation—one of them from Tycho’s friend Caspar Peucer—Tycho agreed to accept Frobenius as a student. He would have free bed and board and an assigned seat at the dinner table.

Though several languages were spoken at Uraniborg, Danish was the most common, and Frobenius knew no Danish. From the start he felt excluded, particularly at meals, where he was seated beside a student
from Bergen, Norway. However, things must have gone rather well, for about a month after his arrival Tycho asked him, through other students, whether he would like to remain at Uraniborg “to serve him in the study of astronomy.” Frobenius replied enthusiastically. He would be pleased to stay for one, two, or three years, if the terms of employment were acceptable. Since most contracts for service
at Uraniborg were for three years or less, Frobenius had not asked for special favors.

Nevertheless, at this point there was a mysterious alteration in Tycho’s attitude toward Frobenius. The conditions of the contract, as Tycho laid them down, seemed intentionally framed to make it impossible for Frobenius to accept. Frobenius was shocked and somewhat affronted to hear that one, two, or three
years were out of the question. He would have to commit himself for six years minimum, pledge never to reveal anything about Tycho’s inventions to anyone either now or after he left, take no notes for his own benefit or later personal use, and “serve without hesitation wherever [he] could fruitfully be used, in any of [Tycho’s] astronomical or pyronomical labors.” He would eat at Tycho’s table,
but there would be no salary or clothing provided by Tycho, who preferred “to grant to me whatever happened to come my way.”

Frobenius took a deep breath and asked for time to consider. Then he replied that he could not agree to such a long period as six years. He wanted to visit foreign lands and learn foreign languages—
as
Tycho himself had done—and eventually probably pursue a career in
medicine or law. Though he was willing to promise not to reveal or spread abroad any information about Tycho’s inventions or observations, he was reluctant to promise never to utilize knowledge gained at Uraniborg to benefit his own studies, for it would be a waste of time to learn things he could never use in the future. Also, he needed a fixed salary, not just bed and board.

Contract negotiations
with prospective assistants were not unusual, and Tycho was often willing to bend on the length of service and adjust other clauses. Not so in the case of Frobenius. Meanwhile Frobenius learned that his situation was disturbingly paradoxical, for though Tycho’s terms of employment seemed designed to force him to leave, other students and assistants told him that it was extremely difficult
to get away from Uraniborg. Hans Crol, who was, like Frobenius, German, said it would be impossible to escape the island unless he could find a good pretext.

The distraught Frobenius recalled that he had in his possession letters of reference to other people besides Tycho, one of which might provide him with an excuse to take a leave of absence from which he would simply not return. The letter
that looked most promising was to Heinrich Rantzau in Holstein. Frobenius requested leave for only a few weeks to go to Holstein, claiming to have been entrusted with an oral message to Rantzau that could not be delivered by anyone else. At first Tycho, perhaps suspecting Frobenius’s intentions, refused his permission. Frobenius then offered to leave all his belongings in his trunk at Uraniborg
as security for his return. Tycho finally acquiesced, with the strange requirement that Frobenius seal the trunk on all sides. Tycho and Frobenius traveled together to Copenhagen. When they parted so that Tycho could attend a meeting of the Rigsraad, Frobenius found a ship bound for Lübeck, hurried aboard, and sailed away with only “a couple of shirts, a cloak, and handkerchiefs in a black linen
satchel.”

It is tempting to wonder whether some of Tycho’s assistants were
playing
a practical joke on poor Frobenius, whether he made the story up, or whether he was perhaps a difficult and vindictive person himself. Tycho in fact allowed many students and assistants to leave Uraniborg for posts elsewhere. Most continued to be his good friends, and he viewed it as an advantage to have a network
of them all over Europe. Crol, who warned Frobenius about the difficulty of escaping, was at the time an embittered man because of the recent death of his son. Crol himself never left Uraniborg and died in the autumn of that same year. Tycho grieved for him and praised his memory as a fine goldsmith, instrument maker, and observer.

Conflicting opinions and reports are, of course, not unusual
about men and women whose lives for one reason or another tower over the people around them. On the one hand there are those who revere them and either do not experience or choose to forgive treatment that others regard as insulting or abusive. On the other hand there are those who, wearing different spectacles or having somehow inadvertently fallen foul, experience that greatness as having a nasty
side indeed.

fn1
Frobenius’s story remained unknown until John Robert Christianson discovered his memoirs in the late 1980s.

11

Y
EARS OF
D
ISCONTENT

1588–1596

IN THAT SAME
spring of 1591, when Pedersen was in Tycho’s dungeon and Frobenius was upstairs plotting his escape from Uraniborg, Tycho received a letter from Wilhelm, the landgrave in Kassel, asking about an animal that Wilhelm called a Rix.
¹
Wilhelm had heard that a Rix was taller than a deer and native to Norway, and he inquired whether Tycho might
have a picture painted of a Rix and sent to him. Tycho suspected that the landgrave meant a reindeer and was hinting that Tycho might send not merely a picture but the animal itself. Tycho did not have a reindeer, but he had an elk, so he offered to send that. No, the landgrave replied, he already had an elk, and it was not a reindeer he wanted either. He had had one of those before, and it had
not survived in the climate of Kassel. A Rix was what he wanted. Nevertheless, he would not turn down an elk or two if offered.

Tycho had an elk brought from Norway to Copenhagen, where it was to wait at his niece’s home until it could be shipped. Unfortunately, the elk mounted the steps of the manor house, got into the beer supply, and consumed so much beer that it fractured a leg trying
to get back down the stairs and died.

In the course of correspondence with Wilhelm around this pitiful
story
, the first hint came from Tycho himself that he was not entirely happy. He went so far as to tell Wilhelm in rather cryptic language that he might choose to venture into other climes, the sky above being available for study anywhere. He did not specify what was troubling him. Perhaps
it was only a temporary low mood or annoyances like Pedersen and Frobenius that he had largely brought on himself. But there is reason to suspect that one cause of Tycho’s discontent, and his poor handling of those annoyances, was something more significant—a crushing disappointment in his astronomy.

Tycho did not, in this correspondence with Wilhelm, learn of Bär’s visit to Kassel, but Bär
had never been far from Tycho’s mind. Tycho’s book about the comet, with the chapter about the Tychonic system, had come out in April 1588. He mentioned nothing about the success of the 1587 parallax observations in the book, but not long after its publication he wrote to his friends
²
Caspar Peucer and Christoph Rothmann, saying that he had observed the parallax
all the way back in 1582
. That
claim flatly contradicted an earlier letter that he had written in 1584 to a professor with whom he had studied at Rostock, Heinrich Brucaeus. Tycho had reported to Brucaeus that in the observations made in 1582, he had been unable to find a parallax for Mars, and that the Copernican hypothesis had therefore to be rejected. In 1587 he had seemed a little less certain of that negative result when he
had written Wilhelm, in Kassel, that (based on those same 1582 observations) he was more confident he would find a parallax. Then, in 1588, he told Peucer and Rothmann (still referring to the same 1582 observations) that he had finally succeeded. In November 1589 he repeated that claim in a letter to Thaddeus Hagecius, stating once again that all the way back in 1582 (two years before his 1584 letter
to Brucaeus saying the opposite) he had observed a diurnal parallax and that it had been large enough to convince him that Mars comes closer to Earth than the Sun does. In the same letter to Hagecius, Tycho also spoke of the Tychonic system that he had “thought out . . . very nearly six years ago.”

The puzzle was, and is, why the 1582 observations were so important to Tycho that he kept harking
back to them, making contradictory claims about their results. He had designed and built several instruments after 1582 that were much more capable of making this measurement. Kepler later examined Tycho’s observations of 1582
³
and reported that he could find no evidence in them for a Mars parallax. Subsequent knowledge of the solar system has confirmed that there could have been no evidence of
one there. Yet in 1588 and 1589 Tycho’s letters insisted there was.

The explanation for the contradictory claims
^fn1
almost certainly had to do with Bär. Six months after Tycho published the book with the chapter about the Tychonic system in April 1588, Bär also published a book entitled
Fundaments of Astronomy
. In it he laid out a system he claimed was his own invention. Except for some details,
it was identical to Tycho’s system. Tycho’s nightmare had come true. It was of utmost importance to establish priority, and to make it indisputably clear that Bär had learned of the system from Tycho, not Tycho from Bär. One way to accomplish this was to prove that not only the idea of the system, but observations to demonstrate its superiority, predated Bär’s visit to Hven. Certainly this
provided ample motivation for letters to other scholars in which Tycho made claims about the 1582 observations. In fact, the date itself was far more important than the findings, and that was fortunate.

In the autumn of 1589, after he had written to Hagecius, Tycho almost immediately turned his attention again to the problem of refraction. He did so with considerable trepidation. He had complete
confidence in his Mars observations of 1587, but he knew he did not have as much evidence to support the use of his table of solar refraction, the table he had used in 1587 when correcting the positions of Mars to take refraction into account.