Tycho and Kepler (35 page)

Figure 15.2: In this drawing, the borders of the planet’s sphere are shown by broken lines, the orbit by a continuous line. The sphere of a planet had to be roomy enough to accommodate the planet’s eccentricity. In other words, the planet had to be able to travel in the parts of the orbit where it was nearest to and farthest from the Sun without breaking out beyond the borders of its sphere.
The more eccentric the orbit, the thicker the sphere needed to be.

Kepler soon wrote to Mästlin about a clever way he had found to relate his arrangement of the Platonic solids to three of the five intervals in his chord. It was the sort of connection Kepler loved. The polyhedron that separated the spheres of Saturn and Jupiter in his theory was a cube. Each corner of a cube is the meeting
place of three flat squares, and the corner of each of the three squares is a ninety-degree angle. Add those three angles together, and the sum is 270 degrees. The ratio between 270 and 360 (the number of degrees in a complete circle) is 3:4. Thus it seemed appropriate to Kepler that the musical interval that requires a ratio of string lengths 3:4 should define the space interval between Saturn and
Jupiter. Similar relationships worked for the interval between Jupiter and Mars and between Earth and Venus.

Kepler confided to Mästlin and Herwart von Hohenburg, later in the summer, that having come thus far with his harmonic theory, he felt as though he had “a bird under a bucket.”
⁸
His sense was that the
harmony
he was suggesting reflected the mind of the Creator and therefore surely had
to be carried out in the cosmos. Kepler thought he was close to an answer. In fact, it would be twenty years before he found it, and when he did, he would also have discovered his third law of planetary motion.

In the meantime, Kepler’s great frustration was that being so near, he believed, to resolving the discrepancies in his theories, he lacked precise, accurate values for the observed
eccentricities of the planets and the dimensions of the solar system. Kepler had no astronomical instruments of sufficient quality to make the necessary observations himself. The only man in the world who did was Tycho.

Kepler also longed to know whether Tycho’s observations revealed any tiny differences in the altitudes of the Pole Star at the winter solstice and the equinoxes. The absence
of any stellar parallax shift was still a difficulty for a Copernican, because the shift ought to be visible as Earth orbited the Sun. Kepler remained troubled by the fact that Copernican astronomy, combined with the absence of stellar parallax, required the stars to be so inconceivably far away.

At the same time, Kepler had little respect for the “patchwork” Tychonic system, no matter who
had thought of it, Tycho or Ursus. To Mästlin he wrote of Tycho’s ideas about the arrangement of the planetary system as “little paper houses” and wondered whether his own theory of celestial harmony might not easily blow them over. However, Kepler also wrote that he was reluctant to contradict a man like Tycho, especially since he needed Tycho’s observations. If only, he complained, Tycho would
publish
them so they would be widely available, or, failing that, be persuaded to send Kepler the information he needed. “I did not wish to be discouraged, but to be taught,” Kepler complained to Mästlin, rankled by the reservations about
Mysterium
that Tycho had expressed. Kepler could hardly contain his impatience. “My opinion about Tycho
⁹
is this: he has abundant wealth. Only, like most rich
men, he does not know how to make proper use of his riches. Therefore, one must take pains to wring his
treasures
from him, to get from him, by begging, the decision to publish all his observations without reservation.”

To Kepler, Tycho was coming to resemble the dragon nesting on a hoard of gold, not able to put it to use in a meaningful way himself, not even recognizing its true value, but
too fearful of thieves to allow anyone else to glimpse it. Kepler was not above putting his mind to scheming. There must be other ways to get at this hoard than “by begging the decision to publish.”

16

P
RAGUE
O
PENS
H
ER
A
RMS

July 1599–February 1600

TYCHO BRAHE’S RECEPTION
in Prague quickly allayed all fears that his journey might have been in vain. Johannes Barvitius, the emperor’s private secretary and one of the triumvirate who had brokered Tycho’s relationship with the imperial court, met him in a garden near Rudolph’s palace. Tycho showed him the three books he had brought
for Rudolph and the letters of introduction. Barvitius said he would find out in what way and from whom Rudolph wished to receive them. The answer Tycho hoped for came a day later: The emperor wanted to receive them from Tycho himself, and he would be summoned into Rudolph’s presence shortly.

Meanwhile other high-ranking officials at the imperial court welcomed Tycho warmly and expressed their
outrage that King Christian had so sadly undervalued his achievements. Tycho replied diplomatically by defending the Danish king and praising his talents. When the discussion turned to the ignorance and villainy of others at the Danish court, Tycho was only slightly more willing to agree but quickly turned the conversation by commenting that “perhaps God has acted by some special providence in
order that the astronomical investigations with which I have been so long and so thoroughly
occupied
should now come elsewhere and redound to the credit of the emperor himself.”

Barvitius drove Tycho in his carriage to “a splendid
¹
and magnificent palace in the Italian style, with beautiful private grounds,” situated on the pinnacle of the same hill on which Rudolph’s glorious, sprawling complex
stood. Barvitius pointed out the advantages of the mansion, including a tower that might serve for astronomy, and told Tycho that if he liked it, the emperor was willing to purchase it for him.

While they toured the house and grounds, Tycho found subtle ways of letting Barvitius know “from what I said
²
and did not say” that the tower was inadequate to hold even one of his instruments and that
he was not overjoyed with the house. The emperor had foreseen this possibility, and Barvitius was immediately able to mention several castles outside Prague, reachable within a day or two, where there would be fewer disruptions, fewer envious eyes, and a situation nearer to what Tycho had enjoyed at Uraniborg. Barvitius also informed Tycho that Rudolph was prepared to give him an annual stipend,
which Tycho would hear more about when he had his audience.

When the summons came, Tycho had the rare honor of entering Rudolph’s audience chamber alone. “I saw [the emperor]
³
sitting in the room on a bench with his back against a table, completely alone in the whole chamber without even an attending page. After the customary gestures of civility, he immediately called me over to him with
a nod, and when I approached, graciously held out his hand to me. I then drew back a bit and gave a little speech in Latin.” Rudolph replied with equal grace, “saying, among other things, how agreeable my arrival was and that he promised to support me and my research, all the while smiling in the most kindly way so that his whole face beamed with benevolence. I could not take in everything he said
because he by nature speaks very softly.” Tycho thanked the emperor and excused himself to fetch the three presentation copies of his books that he had left with his son Tycho in the antechamber.
Rudolph
“took them and laid them out on the table. I reviewed the contents of each briefly. Then he again responded with a splendid speech, saying most graciously that they would please him greatly. I
then removed myself according to the proper courtesies.”

Rudolph called Barvitius into the audience chamber. Barvitius emerged again almost immediately to tell Tycho that Rudolph had been watching from his window as Tycho arrived and had noticed a mechanical device on Tycho’s carriage. He now wished to have it shown to him. The device was Tycho’s odometer.
⁴
Tycho ordered his son to fetch it
and gave it to Barvitius with a quick explanation of its construction and operation. Barvitius soon came back out of the audience chamber to report that the emperor did not want to accept Tycho’s odometer but would have one made for himself according to its pattern. This was Tycho’s first experience of one of the emperor’s eccentricities. Rudolph was a fanatical collector of curiosities and was
far happier among these objects than among people.

Barvitius reported that “the emperor was very favorably
⁵
disposed toward [Tycho] and that after he referred the case to his council, in a short time, he would settle the matter of an annual grant and suitable quarters.” Tycho was encouraged to summon his family to join him, and the “emperor himself would do everything necessary to make sure
that we lacked for nothing needed to live comfortably.” Tycho sent his son to bring Kirsten and the others from Dresden. They all arrived eight days later.

It was urgent that Tycho have an estate that he could begin turning into a new Uraniborg, and, true to his word, Rudolph gave Tycho a choice among three estates some distance from the city, including his own favorite hunting lodge, Brandeis—a
huge, magnificent establishment. Perhaps thinking of what a sacrifice the emperor would be making if he accepted it, Tycho chose another castle farther along the same road, a six-hour ride from Prague. Handsomely positioned on a bluff sixty meters above the flood plain of the river Jizerou, this was the castle Benatky, the Czech name for Venice, because when the area
flooded
, the promontory where
the castle stood was surrounded by water. The mansion, like Uraniborg, was not ancient and had never been intended to serve as a fortress. Also like Uraniborg, it boasted an indoor water system, probably the first in Bohemia. Tycho was taken by the beauty of the surroundings and by Benatky’s uninterrupted view of the horizon in all directions, and he even noted with approval that there was, nearby,
a small village of Protestants with Calvinist leanings.

By late August Tycho and his family had explored the bright, spacious rooms of the castle and were deciding how they should be allotted and where the furniture should go. The indoor space was larger than Uraniborg, with three floors of nearly 5,380 square feet each. Though none of this space was well suited for astronomy, Tycho was setting
up his instruments. Rudolph had by now had time to peruse the pictures in Tycho’s
Mechanica
, and he was eager to see Benatky become even greater than Uraniborg.

Tycho began the transformation of the castle by making repairs, but it was not long before he was modifying the floor plan and windows and designing additional buildings to house the instruments and alchemical laboratories. He took
observations to calculate the exact geographical position and orientation of his new home, and he marked the meridian with a line on the floor near a window. Benatky wasn’t oriented along north-south, east-west lines, as Uraniborg had been, but then it had not been designed by an astronomer.

Tycho’s annual grant took longer than expected to pass the council. The outlay for Tycho was to be
higher than the salaries of many counts and barons in the emperor’s service. Eventually Rudolph even ordered that Tycho’s salary be retroactive from the time his patronage in Denmark had ended, and Tycho was to have a hereditary fief as soon as one became available. However, shortly after Tycho began his remodeling, the administrator of the estate, Caspar von Mühlstein, began complaining to Barvitius
about the mounting costs. By late November, Tycho’s renovation estimates had doubled, and
Mühlstein
had also learned that the salary the emperor had promised Tycho was much greater than the income from the Benatky estate. Mühlstein refused to authorize any more expenditure without an official order backed up with money from the treasury. He knew, as Tycho would soon discover for himself, that
much of Rudolph’s munificence was, in fact, financial make-believe. Unlike in Denmark, where the king’s word was his bond and bound everyone else as well, in the imperial court promises often rested on nothing but good intentions, orders on the royal treasury would fail to produce payment, and there might not even be sufficient money in the treasury to make good on Rudolph’s pledges.

Tycho
soon found that in other respects as well the emperor’s favor did not make all things possible. The promised hereditary fief could not be Tycho’s until he had applied for and obtained citizenship, a slow bureaucratic process. His friends warned him that envy and slander were as much a part of court life here as they had been in Denmark, and there were opportunists eager to bring him down. Powerful
men who had not been part of Tycho’s network were not pleased to be shouldered aside by a foreigner.

However, it also was not long before officials and administrators such as Mühlstein began to realize the seriousness of Rudolph’s intentions to underwrite Tycho’s work. The court had again left Prague for fear of plague, taking with them some of Tycho’s medicines, but letters passed frequently
between Tycho and the emperor. Tycho’s messages went straight to Rudolph without perusal by the Imperial Council. With the emperor giving him this much priority, Tycho felt so confident that he threatened the foot-dragging Mühlstein with Rudolph’s displeasure and hinted that if the expenditures were not authorized he might “leave Bohemia
⁶
and tell the world why.” The Chamber of Deputies informed
Mühlstein that, awaiting Rudolph’s clarification, he should continue construction at Benatky as cheaply as possible.