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TYCHO BRAKE.



OF THE

UK 1 7. ZR SIT 7




TYCHO BRAKE



A PICTURE OF

SCIENTIFIC LIFE AND WORK IN THE
SIXTEENTH CENTURY



BY



J. L. E. >REYER, PH.D., F.R.A.S.

DIRECTOR OF THE ARMAGH OBSERVATORY



THE

UHIVERSIT7




EDINBURGH

ADAM AND CHARLES BLACK
1890



TO

RALPH COPELAND,

PH.D., F.R.S.E., &C.,
ASTRONOMER ROYAL FOR SCOTLAND,



JSoofc ie 5)eDfcate&

BY HIS FRIEND

THE AUTHOR.



PBEFACE.



ASTRONOMERS are so frequently obliged to recur to observa-
tions made during former ages for the purpose of supporting
the results of the observations of the present day, that there
is a special inducement for them to study the historical
development of their science. Much labour has accordingly
been spent on the study of the history of astronomy, and in
particular the progress of the science in the sixteenth and
seventeenth centuries has of late years formed the subject of
many important monographs. The life of Copernicus has
been written in considerable detail by Prowe, Hipler, and
others. Of Kepler's numerous works we owe a complete
edition to the patient industry and profound learning of the
late Dr. Frisch of Stuttgart, while the life of Galileo, and
particularly his persecution and trial, have called forth quite
a library of books and essays. In the present volume I
have attempted to add another link to the chain of works
illustrating the birth of modern astronomy, by reviewing
the life and work of Tycho Brahe, the reformer of observa-
tional astronomy.

Although not a few monographs have been published
from time to time to elucidate various phases in the career of
Tycho Brahe, while several popular accounts of his life (by
Helfrecht, Brewster, &c.) have appeared, the only scientific



viii PREFACE.

biography hitherto published is that of Gassendi. This
writer obtained valuable materials from some of Tycho
Brahe's pupils, and from the Danish savant Worm, but he
chiefly derived his information from a close scrutiny of
Tycho's own writings, never failing to make use of any
particulars of a biographical nature which might be recorded
in passing by Tycho. In studying Tycho's works, I have
repeatedly come across small historical notes in places where
nobody would look for such, only to find that Gassendi had
already noticed them. In 1745 a biography was published
in a Danish journal (Bang's Samlinger, vol. ii.), the contents
of which are chiefly taken from Gassendi, but which also
contains a few documents of interest. Of far greater im-
portance is a collection of letters, royal decrees, and other
documents, published in 1746 by the Danish historian Lan-
gebek in the Danske Magazin, vol. ii., which still remains
the principal source for Tycho's life. A German translation
of this and the memoir in Bang's Samlinger was published
in 1 7 5 6 by Mengel, a bookseller in Copenhagen, who wrote
under the high-flown pseudonym Philander von der Wei-
stritz ; and as his book has naturally become more generally
known than the Danish originals, I have, when quoting
these, added references to Weistritz's book. During the
present century several Danish historians have brought to
light many details bearing on Tycho's life which will be
referred to in this volume; and in 1871 a Danish author,
F. R. Friis, published a popular biography in which were
given various hitherto unpublished particulars, especially
of Tycho's beneficiary grants and other endowments. The
same writer has also published a number of letters ex-
changed between Tycho and his relations, and various con-
temporary astronomers. Of great scientific interest is the
correspondence between Tycho and Magini, published and



PREFACE. ix

commented by Professor Favaro of Bologna with the care
and learning by which the writings of this author are
always distinguished. Some other letters from the last
years of Tycho's life have recently been published by Pro-
fessor Burckhardt of Basle. Lastly, we must mention the
meteorological diary kept at Uraniborg, which is of great
historical value as affording many interesting glimpses of
Tycho Brahe's home life. It was published in 1876 by
the Eoyal Danish Society of Science.

Among other publications of importance for the study
of Tycho Brahe's life and activity must be mentioned the
biography of Kepler, by Frisch, in the last volume of
Kepler's Opera Omnia, and several papers by Professor
Kudolph Wolf of Zurich on Landgrave Wilhelm of Hesse-
Cassel, and his astronomers Kothmann and Btirgi. Though
only indirectly bearing on Tycho (of whose merits Professor
Wolf on every occasion speaks somewhat slightingly), these
valuable papers throw much light on the state of science at
the end of the sixteenth century, and will often be found
quoted in the following pages.

Having for many years felt specially interested in Tycho
Brahe, it appeared to me that it would be a useful under-
taking to apply the considerable biographical materials
scattered in many different places to the preparation of a
biography which should not only narrate the various inci-
dents in the life of the great astronomer in some detail, but
also describe his relations with contemporary men of science,
and review his scientific labours in their connection with
those of previous astronomers. The historical works of
Montucla, Bailly, Delambre, and Wolf have indeed treated
of the astronomical researches of Tycho Brahe, but as the
plans of these valuable works were different from that
adopted by me, I believe the scientific part of the present



x PREFACE.

volume will not be found superfluous, particularly as it is
founded on an independent study of Tycho's bulky works.
To these I have given full references for every subject, so
that any reader may find further particulars for himself
without a laborious search. Many details, especially as to
the historical sequence of Tycho's researches, have been
taken from his original MS. observations in the Royal
Library at Copenhagen, which I was enabled to examine
during two visits to Copenhagen in 1888 and 1889. On
the same occasions I also studied three astrological MSS.
of Tycho's, of which an account will be found in Chap-
ter VI. It may possibly be thought by some readers that
I have devoted too much space to the consideration of
the astrological fancies of the Middle Ages. But my
object throughout has been to give a faithful picture of the
science of the sixteenth century, and for this purpose it is
impossible to gloss over or shut our eyes to the errors of
the time, just as it would be absurd, when writing the
scientific history of other periods, to keep silence as- to the
phlogistic theory of combustion, the emission theory of
light, or the idea of the sun as having a solid nucleus. If
the study of the history of science is to teach us anything,
we must make ourselves acquainted with the by-paths and
blind alleys into which our forefathers strayed in their
search for truth, as well as with the tracks by which they
advanced science to the position in which our own time
finds it.

With the exception of the astronomical manuscripts in
the Royal Library at Copenhagen (for facilities in using
which I was indebted to Dr. Bruun, chief librarian), I have
not made use of any unpublished materials ; but the scanty
harvest reaped by modern searchers makes it extremely
unlikely that anything of importance remains to be found



PREFACE. xi

among unpublished sources. I believe, however, that certain
periods of Tycho Brahe's life in this volume will be found
to appear in a light somewhat different from that in which
previous writers have seen it. Especially it seems difficult
to deny that Tycho's exile was almost entirely due to him-
self, and that there was no absolute necessity for his leaving
Hveen, even though he had lost most of his endowments.
As an amusing instance of the manner in which many inci-
dents have been misunderstood by those who consider Tycho
a martyr of science, we may mention that the trouble into
which the minister of Hveen got with his superiors and
with his parishioners (for his unwarranted interference with
the Church ritual), has been described as a riot or fight,
instigated by a wicked statesman, in which Tycho's shepherd
or steward (pastor !) was injured.

I should scarcely have been able to write this book far
from great libraries if I had not for many years taken every
opportunity of acquiring books or pamphlets bearing in any
way on the subject, or of making excerpts from such as
could not be purchased. I have, however, been under great
obligations to the Astronomer Royal for Scotland, who most
kindly allowed me to consult the literary treasures on the
star of 1572 in the Crawford Library of the Royal Observa-
tory, Edinburgh. Hereby I have been enabled to examine
even some writings on the new star which were unknown
to Tycho Brahe.

That I have adopted the Latin form of the astronomer's
name, by which he is universally known, instead of his real
baptismal name of 'Tyge, scarcely requires an apology. It
would indeed only be affectation to speak of Schwarzerd or
Koppernigk instead of Melanchthon or Copernicus. The
portrait of Tycho Brahe in this volume (about which see
p. 264) has already appeared in Woodburytype in the



xii PREFACE.

Memoirs of the Literary and Philosophical Society of
Manchester, vol. vi., and in woodcut in Nature, vol. xv.
Most of the other illustrations are taken from Tycho's own
works. For photographs, from which the illustrations in
Chapter XI. were made, I am indebted to Professor Safarik
of Prague, who has also kindly communicated various par-
ticulars about Tycho's life in Bohemia.



J. L. E. DREYER



THE OBSERVATORY, ARMAGH,
September 1890.



CONTENTS.



CHAPTER I.
THE REVIVAL OF ASTRONOMY IN EUROPE.

PAGE

Revival of science in Germany Purbach Greek astronomy
studied Regiomontanus Ephemerides Walther Apianus

Copernicus New system of the 'world proposed State of
astronomy in the sixteenth century . . , . . i

CHAPTER II

TYCHO BRA HE'S YOUTH.

Family Childhood At Copenhagen University Becomes in-
terested in astronomy Sent to Leipzig Commences to
take observations Returns home Stay at Wittenberg
At Rostock At Augsburg Construction of a large quadrant

Resides at Heridsvad Chemical studies . . . .10

CHAPTER III.

THE NEW STAR OF 1572.

First appearance Tycho's observations His book on the star
His calendar for 1573 Other observations of the star'
Measurements Moment of first appearance Opinion as to
nature of star Alleged earlier appearances of new stars
Its supposed significance ....... 38

CHAPTER IV.

TYCHO'S ORATION ON ASTROLOGY AND HIS
TRA VELS IN



Tycho's wife and children Oration on astrology Travels in
Germany Landgrave Wilhelm IV. King Frederick II.
Island of Hveen granted to Tycho Pension .... 70




xiv CONTENTS.

CHAPTER V.

THE ISLAND OF HVEEN AND TYCHO BRA HE'S OBSER-
VATORIES AND OTHER BUILDINGS HIS ENDOW-
MENTS.

PAGE

Description of Hveen Local traditions Uraniborg Instru-
ments Stjerneborg Observatory Grant of Kullagaard manor
Prebend of Roskilde Nordfjord estate in Norway . . 88

CHAPTER VI.

TYCHO'S LIFE AT HVEEN UNTIL THE DEATH OF
KING FREDERICK II.

Home life Printing press Tenants at Hveen Students and
assistants Flemlose Wittich Elias 01 sen Longomon-
tanus Chemical researches Correspondence Visitors
Relations with the King Horoscopes of Princes Tycho's
opinion of judicial astrology Death of the King . . .114

CHAPTER VII.

TYCHO'S BOOK ON THE COMET OF 7577, AND HIS
SYSTEM OF THE WORLD.

Comet of 1577 Six other comets Tycho's book on cornet of 1577
Comets celestial objects Tychonic system of the world
System of Copernicus yet incomplete Reymers (Ursus) and
his system .158

CHAPTER VIII.

FURTHER WORK ON THE STAR OF 1572.

Tycho's larger book on the star Its great distance Dimensions

of the universe Nature of star Its astrological effect . 186

CHAPTER IX.

THE LAST YEARS AT HVEEN, 1588-1597.

New Government New grant to Tycho House at Copenhagen

Sophia Brahe Visit of James VI. Visit of Rotlmiann
Correspondence with the Landgrave and Magini Visit of
the young King Tycho's quarrel with a tenant Neglects to
repair chapel of his prebend Quarrel with Gellius Volume
of Epistles Accession of King Christian IV. Tycho de-
prived of Norwegian fief Valkendorf Pension stopped

Tycho leaves Hveen Troubles about clergyman at Hveen . 198



CONTENTS. xv

CHAPTER X.

TYCHO'S LIFE FROM HIS LEAVING HVEEN UNTIL
HIS ARRIVAL AT PRAGUE.

PAGE

Tycho at Copenhagen Departs for Eostock Letter to the King
Lends money to the Dukes of Mecklenburg The King's
reply Tycho at Wandsbeck Vain attempts to reconcile the
King Publishes description of instruments Star catalogue
Calumnies of Eeymers Invitation from the Emperor
Tycho winters at Wittenberg 239



CHAPTER XL
TYCHO BRAHE IN BOHEMIA HIS DEATH.

Rudolph II. Tycho's salary Castle of Benatky Financial
difficulties Work resumed Kepler's youth His arrival at
Benatky and quarrel with Tycho Reconciliation Tycho
settles at Prague His assistants Solar and lunar theory
Tycho's death and funeral 277

CHAPTER XII.
TYCHO BRAHE' S SCIENTIFIC ACHIEVEMENTS.

Zodiacal and equatorial armillse Meridian quadrant Altazi-
muth quadrant Time determinations Sextants for distance
measures Subdivision of arcs Nonius Transversal
divisions Improved pinnules Theory of sun's motion Re-
fraction Lunar theory Discovery of lunar inequalities
Kepler and the annual equation Motion of planets Posi-
tions of fixed stars Absolute longitude Star catalogue
Precession Trepidation disproved Accuracy of observations
Alleged error of Tycho's meridian Trigonometrical
formulas 315



APPENDIX.

Fate of Tycho's instruments His family in Bohemia Publica-
tion of his books Tycho's manuscript observations Hveen
after Tycho's time . . . . ' 365



xvi CONTENTS.



NOTES.

PAGE

Specimen of Tycho's early observations with the cross-staff List
of Tycho Brahe's pupils and assistants Tycho's opinion
about astrological forecasts Kepler's account of Tycho Brahe's
last illness Comparison of Tycho Brahe's positions of stan-
dard stars with modern results On the alleged error of
Tycho's meridian line Huet's account of the state of Hveen
in 1652 Catalogue of the volumes of manuscript observa-
tions of Tycho Brahe in the Koyal Library, Copenhagen
Bibliographical Summary 381



PLATES.

PORTRAIT OF TYCHO BRAHE . . . . Frontispiece

MURAL QUADRANT To face p. 101

CASTLE OF BENATKY . ,, 282

FERDINAND I.'s VILLA ,,298

TYCHO'S TOMBSTONE . 311

(The above by S. B. BOLAS & Co., London.)



ERRATA.

Page 54, last line, for " Locus in Sagit.," read " Locus in Sagit."

66, Footnote 2, line 7 from end, add : That Hardeck speaks of the
comet of 1264, although he gives the year 1260, may be seen
from his references to Pope Clement IV. (1265-1268) and the
battle of Benevent (1266). According to Pingr^, several writers
have been confused with regard to the year of this comet.
127, line 2, for " Coll," read " Crol."



^

UHIVERSITT




TYOHO BEAHE,

CHAPTER I.
THE REVIVAL OF ASTRONOMY IN EUROPE.

THE early part of the sixteenth century must always rank
among the most remarkable periods in the history of
civilisation. The invention of printing had made literature
the property of many to whom it had hitherto been in-
accessible, and the downfall of the Byzantine Empire had
scattered over Europe a number of fugitive Greeks, who
carried with them many treasures of classical literature
hitherto unknown in the Western world, while Raphael,
Michael Angelo, and other contemporaries of Leo X. revived
the glory of the ancients in the realm of art. The narrow
limits of the old world had vanished, and the Portuguese
and Spanish navigators had led the way to boundless fields
for human enterprise, while the Reformation revolutionised
the spirit of mankind and put an end to the age of ignorance
and superstition.

During this active period there were also signs of renewed
vigour among the devotees of science, and the time was
particularly favourable to a revival of astronomical studies.
Students of astronomy were now enabled to study the
Greek authors in the original language, instead of having
to be content with Latin reproductions of Arabian transla-
tions from the Greek, which, through the Italian Univer-

1



2 TYCHO BRAKE.

sities, liad been introduced into Europe during the Middle
Ages. Another impulse was given by the voyages of
discovery, as navigators were obliged to trust entirely to
the stars and the compass, and therefore required as perfect
a theory as possible of the motions of the heavenly bodies.
We see accordingly at the end of the fifteenth century
and the beginning of the sixteenth considerable stir in the
camp of science, but as yet only in Germany a circumstance
not difficult to explain. Though divided into a great
number of semi-independent states, Germany "bo/e still the
proud name of the Holy Eoman Empire, and on account of
the claims represented by this name the Germans had for a
long time been in constant intercourse with Italy, the land
with the great past, and still, notwithstanding its political
misery, the leader of civilisation. It was an intercourse of a
peaceful and commercial as well as of a warlike character ;
but in both ways was this of benefit to the Germans, pro-
ducing among them much knowledge of foreign affairs, and
giving them greater facilities for taking up the scientific
work of the ancients than were found in other parts of
Europe.

The first astronomer of note was Georg Purbach (1423
1461), who studied at the University of Vienna, and
afterwards for some time in Italy. His principal work
on astronomy (Theories Novce Planetarum) attempted to
develop the old hypothesis of material celestial spheres,
and was but a mixture of Aristotelean cosmology and
Ptolemean geometry ; but he was the first European to
make use of trigonometry, the principal legacy which
astronomers owe to the Arabs. Purbach endeavoured to
get beyond the rudiments of spherical astronomy, which
hitherto had formed the only subject for astronomical
lectures, and had been taught through the medium of a
treatise written in the thirteenth century by John Holy-



REVIVAL OF ASTRONOMY IN EUROPE. 3

wood (Johannes de Sacrobosco) for use in the University of
Paris. While lecturing at Vienna, Purbach's attention was
drawn to a young disciple of great promise, Johann Miiller,
from Konigsberg, a small village in Franconia, where he
had been born in 1436. He is generally known by the
name of Eegiomontanus, though he does not seem to have
used this name himself, but always that of Johannes de
Monteregio. He entered heart and soul into his teacher's
studies of the great work of Ptolemy, which embodied all
the results of Greek astronomy, and the talented pupil soon
became an invaluable co-operator to Purbach. They did
not confine themselves to theoretical studies, but, with such
crude instruments as they could construct, they convinced
themselves of the fact that the places of the planets
computed from the astronomical tables of King Alphonso X.
of Castile differed very considerably from the actual posi-
tions of the planets in the sky. 1 In the midst of these
occupations the two astronomers had the good luck to
become acquainted with a man who was well qualified
to help them to carry out their greatest wishes. This
man was Cardinal Bessarion, a Greek by birth, who, as
Bishop of Nicaea, had accompanied the Byzantine Emperor
on his journey to the Council of Ferrara in 1438, where
he tried to bring about a reconciliation between the Greek
and Roman Churches. Bessarion remained in Italy and
joined the Roman Church, but he never forgot his old
country, and contributed very much to make the classical
Greek literature known in the West. The translation of
the original Almagest (as Ptolemy's work was generally
called, from a corruption of the Arabic Al megist, in its

1 The Tabulae Alphonsinae had been computed in the middle of the
thirteenth century by a number of Arabian and Jewish astronomers under
the personal .direction of King Alphonso el Sabio. They were founded on
the theory of Ptolerny and the observations of the Arabs, and were first
printed at Venice in 1483.



TYCHO BRAKE.



turn derived from fAeyia-rt] crvvTafys) was a subject in which
he was particularly interested, and during his stay at
Vienna as Papal Nuncio he succeeded in communicating to
Purbach his own anxiety to make Ptolemy better known in
the scientific world. Purbach was on the point of starting
for Italy for the purpose of collecting Greek manuscripts,
when he died suddenly in 1461, but Regiomontanus suc-
ceeded to his place in the Cardinal's friendship, and set out
for Italy with Bessarion in the following year.

Regiomontanus stayed about seven years in Italy, visit-
ing the principal cities, and losing no chance of studying
the Greek language and collecting Greek manuscripts. At
Venice he wrote a treatise on trigonometry, which branch
of mathematics he also, during the remainder of his life,
continued to develop, so that he constructed a table of
tangents (tabula fecunda), and probably only was prevented
by his early death from completing his treatise by intro-
ducing the use of tangents therein. 1 After his return to
Germany, he settled, in 1471, at Niirnberg. This city was
one of the chief centres of German industry and literary
life, and no other German city had such regular commercial
communication with Italy, from whence the produce of the
East was brought into the market, and nowhere did the
higher classes of citizens use their wealth so willingly in
support of art and science. The new art of printing had
recently been introduced at Niirnberg, where a regular
printing-press was now working a circumstance of parti-
cular importance to the collector of Greek writings. A
wealthy citizen, Bernhard Walther (born 1430, died 1504),
became at once the friend and disciple of Regiomontanus,

1 The treatise De Triangulis Omnimodis, libri v., was first published at
Niirnberg in 1533, while Regiomontanus himself printed the TabuLw Dircc-
tionum in 1475, containing both a table of sines for every minute, and the
above-mentioned table of tangents for every degree, extended to every
minute by Reinhold in a new edition in 1554.



REVIVAL OF ASTRONOMY IN EUROPE. 5

and arranged an observatory for their joint use. Instru-
ments, as fine as the skilful artisans of Niirnberg could
make them, adorned the earliest of European observatories,
and the two friends made good use of them (they observed
already the comet of 1472), and originated several new
methods of observing. But Eegiomontanus did not forget
the printing operations, and published not only Purbach's
Theories Novce and trigonometrical tables, but also his own
celebrated Ephemerides, the first of their kind, which, some
years afterwards, were made known to the navigators
through the German geographer Martin Behaim, and
guided Diaz, Columbus, Yasco de Gama, and many others
safely across the ocean. Nothing spread the fame of the
astronomer like these Ephemerides, and the Pope was thus
induced to invite Eegiomontanus to Eome to reform the
confused calendar. The invitation was obeyed in 1475,
but Eegiomontanus died in July 1476 very suddenly
at Eome. He only reached the age of forty, and no
doubt much might have been expected from him if death
had not so early stopped his career; but he had rendered
great service to science, not only by his endeavours to save
the Greek authors from oblivion, 1 but by his Ephemerides,
his development of trigonometry, and his observations.
Walther survived him twenty-eight years, and continued
his observations, which were published in 1544.

By Purbach and Eegiomontanus the astronomy of the
Alexandrian school had been introduced at the German
Universities, and the increased demands which navigators
made on astronomers continued to help forward the study
of astronomy in Germany, which country, by having a
sovereign in common with Spain, for a while had much
intercourse with the latter country. Of the astronomers

1 The Greek text of Ptolemy's work from the MS. brought home by
Regiomontanus was published at Bale in 1538.



6 TYCHO BRAHE.

who worked during the first half of the sixteenth century
we shall here mention Peter Apianus or Bienewitz, who
taught at the University of Ingolstadt. Besides other
works, he published in 1540 a large book, Astronomicum
Ccesareum, dedicated to Charles the Fifth. In this beau-
tiful volume the author represented, by means of movable



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