Tycho Brahe: a picture of scientific life and work in the sixteenth century/Chapter 4
TYCHO'S ORATION ON ASTROLOGY AND HIS TRAVELS IN 1575.
After the publication of the book on the new star Tycho Brahe had intended to go abroad for some time, and it appears, even, that he was inclined to leave his native land for ever, but the journey had to be put off owing to an attack of ague, which continued during the greater part of the summer of 1573. Another circumstance which doubtless contributed to keep him at home, was that he had formed an attachment to a young girl some months before. Her name was Christine, but otherwise nothing is known about her; some authors say she was the daughter of a farmer on the Knudstrup property, others that she was a servant-girl; others, again, believed her to have been the daughter of a clergyman. At any rate, it is certain that she was not of gentle blood, and this contributed greatly to estrange his proud relations from him, as they, of course, considered the connection a disgrace. Tycho had no scruples in this respect, and probably considered that a quiet and domestic woman was more likely to be a suitable companion for him through life than a high-born lady to whom his scientific occupations, perhaps, might be distasteful. It is nowhere expressly stated that he and she were united by a Church marriage, and it is almost certain that this was not the case, as it is stated in several contemporary genealogies that Tycho was not married, but that he had children by an "unfree woman." Twenty-nine years after his death his sister Sophia and several others of his relations signed a declaration stating that Tycho's children were legitimate, and that their mother (though his inferior in rank) had been his wife, adding that he would not have been allowed to live with an unmarried woman in Denmark for twenty-six years. But this does not in the least prove that Christine had been formally married to Tycho. According to the ancient Danish law, a woman who publicly lived with a man and kept his keys and ate at his table was after three winters to be considered as his wife. In this rule the Reformation made no change, as Luther and his followers did not consider a Church ceremony necessary to legalise a marriage, but adopted the old rule of canonical law, that the consent of the parties made the marriage, which, therefore, really dated from the betrothal (matrimonium inchoatum), though the full consequences only began when the parties went to live together or were married (matrimonium consummatum). A natural result of these views was, that the parties frequently began to live together immediately after the betrothal, as they did not see the necessity of the Church ceremony, which could make no difference as to the legal effects of the connexion. Gradually a change took place in these views, as the Church could not look with indifference at this setting aside of its authority; but though in Denmark betrothed people about the year 1566 began to be punished if they commenced living together before the wedding, and an ordinance of 1582 declares that a formal betrothal before a minister and witnesses shall precede a wedding, it was not yet expressly ordered that a Church ceremony was the only way of legalising a marriage, and, in fact, this was not done till a hundred years later. Tycho Brahe lived just at a time when the law of the land was still formally unaltered, and it is therefore intelligible how his children might be considered legitimate, and the companion of his life have been looked upon as his lawful wife. Doubtless the only fault anybody had to find with her was her low origin, and if she had been his equal in rank nobody would have thought that she was anything but his wife.
Tycho's eldest child, a daughter of the name of Christine, was born in October 1573, but died in September 1576. His other children were Magdalene (born in 1574), Claudius (born in January 1577, died six days after), Tyge (born in August 1581), Jörgen (born 1583), and three other daughters, Elizabeth, Sophia, and Cecily, as to the dates of whose birth nothing is known.
The ague seems to have left Tycho in August 1573, as we still possess a couple of observations from the 14th of that month. The lunar eclipse of the 8th December, which he had computed in the book on the new star, was duly observed, and he was on that occasion assisted by his youngest sister Sophia, at that time a girl seventeen years of age, highly educated, and not only conversant with classical literature, but also well acquainted with astrology and alchemy, and therefore in every way fit to assist her great brother. She was the only one of his relations who showed any sympathy with his pursuits, and was a frequent visitor in his home. In March, April, and May 1574 Tycho observed at Heridsvad, but the remaining part of the year he chiefly spent at Copenhagen, where his daughter Magdalene was born. In the capital his rising fame had now attracted considerable attention, and some young nobles who were studying at the University requested him to deliver a course of lectures on some mathematical subject on which there were no lectures being given at that time. His friends Dancey and Pratensis urged him to consent to this proposal, but Tycho was not inclined to do so, until the King had also requested him to gratify the wishes of the students, and at the same time to give the University a helping hand. He then yielded, and the lectures were commenced on the 23rd September 1574, with an oration on the antiquity and importance of the mathematical sciences. This was printed after his death, but has long ago become very scarce, for which reason we shall give an abstract of the contents.
The oration begins with an allusion to his having been requested to lecture, not only by his friends, but also by the King, and then goes on to describe the various branches of mathematics cultivated by the ancients. Geometry has a higher purpose than merely measuring land, and the divine Plato turned all those away from his teaching who were ignorant of geometry, as being unfit to devote themselves to other branches of philosophy. To this he attributes the high degree of learning reached by the ancient philosophers, as they were imbued with geometry from their childhood, "while we, unfortunately, have to spend the best years of our youth on the study of languages and grammar, which those acquired in infancy without trouble." Astronomy is a very ancient science, and, according to Josephus, it can be traced back to the time of Seth, while Abraham from the motions of the sun, moon, and stars perceived that there was but one God, by whose will all was governed. It was next studied by the Egyptians; while we owe our knowledge, above all, to Hipparchus, Ptolemy, and more recently to Nicolaus Copernicus, who not without reason has been called a second Ptolemy, and who, having by his own observations found both the Ptolemean and the Alphonsine theories insufficient to explain the celestial motions, by new hypotheses deduced by the admirable skill of his genius, restored the science to such an extent, that nobody before him had a more accurate knowledge of the motions of the stars. And though his theory was somewhat contrary to physical principles, it admitted nothing contrary to mathematical axioms, such as the ancients did in assuming the motions
of the stars in the epicycles and eccentrics to be irregular with regard to the centres of these circles, "which was absurd." The lecturer next alludes to the beauty of the celestial phenomena, and shows that we must distinguish between the casual contemplation of the heavens and their scientific examination, as only the latter will detect the variation in the moon's distance from us, the revolutions of the planets, &c. The utility of astronomy is easy to perceive, as no nation could exist without means of properly dividing and fixing time, while the science exalts the human mind from earthly and trivial things to heavenly ones. A special use of astronomy is, that it enables us to draw conclusions from the movements in the celestial regions as to human fate. The remainder of the lecture is devoted to considerations on the importance and value of astrology, and tries to answer the objections which philosophers and theologians had made against it. It is evident, from the detailed manner in which this is done, how important Tycho considered this subject to be. We cannot, he says, deny the influence of the stars without disbelieving in the wisdom of God. The importance of the sun and moon is easy to perceive, but the five planets and the eighth sphere have also their destination, as they cannot have been created without a purpose, but were placed in the sky and given regular motions to show the wisdom and goodness of the Creator. The sun causes the four seasons, while during the increase and decrease of the moon all things which are analogous to it, such as the brain and marrow of animals, increase and decrease similarly. The moon also causes the tides, and its influence on these becomes greatest when that of the sun is joined to it at new-moon and full-moon. Sailors and cultivators of the soil have noticed that the rising and setting of certain stars cause stormy weather, and more experienced observers know that the configurations of the planets have also great influence on the weather. Conjunctions of Mars and Venus in certain parts of the sky cause rain and thunder, those of Jupiter and Mercury storms, those of the sun and Saturn turbid and disagreeable air. The most ancient writers on agriculture, as well as poets and astrologers, have observed that the rising and setting of the more conspicuous stars simultaneously with the sun produced rain, wind, and other atmospheric changes, particularly when the planets joined their effect to that of the stars. The sun and stars move in the same manner from year to year, but this is not the case with the planets, and the weather of one year cannot, therefore, be like that of another. Among planetary conjunctions, he mentions that of Jupiter and Saturn in 1563, in the beginning of the sign of Leo near the hazy stars of Cancer (Prassepe), which Ptolemy already considered pestilential. This conjunction was in a few years followed by an outbreak of the plague. While many people admitted the influence of the stars on nature, they denied it where mankind were concerned. But man is made from the elements, and absorbs them just as much as food and drink, from which it follows that man must also, like the elements, be subject to the influence of the planets; and there is, besides, a great analogy between the parts of the human body and the seven planets. The heart, being the seat of the breath of life, corresponds to the sun, and the brain to the moon. As the heart and brain are the most important parts of the body, so the sun and moon are the most powerful celestial bodies; and as there is much reciprocal action between the former, so is there much mutual dependence between the latter. In the same way the liver corresponds to Jupiter, the kidneys to Venus, the milt to Saturn, the gall to Mars, and the lungs to Mercury, and the resemblance of the functions of these various organs to the assumed astrological character of the planets is pointed out in a manner similar to that followed by other astrological writers. He believes experience to have shown that those who are born when the moon is affected by the evil planets (Saturn and Mars) and is unluckily placed, have a weak brain and are under the influence of passions, while those in whose case the sun was influenced by those planets suffered from palpitation of the heart. But if both luminaries are in unlucky aspects, those born at that time are of weak health and intellect. Those people at whose birth Saturn, the highest planet, was favourable, are inclined to sublime studies, while those whom Jupiter has influenced are attracted to politics. The solar influence makes people desire honour, dignities, and power; that of Venus makes them devote themselves to love, pleasures, and music; while Mercury encourages people to mercantile pursuits, and the moon to travelling.
Many philosophers and theologians, continued Tycho in his lecture, have contended that astrology was not to be counted among the sciences, because the moment of birth was difficult to fix, because many are born at the same moment whose fates differ vastly, because twins often meet with very different fortunes, while many die simultaneously in war or pestilence whose horoscopes by no means foretold such a fate. It had also been maintained that a knowledge of the future was useless or undesirable, and theologians added that the art was forbidden in God's Word and drew men away from God. To these objections Tycho answered, that even if there was an error of an hour in the assumed time of birth, it would be possible from subsequent events to calculate it accurately. With regard to war or pestilence, prudent astrologers always made a reservation as to public calamities which proceed from universal causes. Difference of education, mode of life, and similar circumstances explained the different fates which people born at the same time met with; and as to twins, they were not born exactly at the same moment, and one was always naturally weaker than the other, and this the stars could not correct. Astrology was not forbidden in the Bible, but sorcery only.
So far Tycho's astrological ideas are in accordance with those of contemporary and previous writers on such subjects, but towards the end of his discourse he shows more distinctly than most of these, that he did not consider the fate of man to be absolutely settled by the aspect of the stars, but that God could alter it as He willed. Nor was man altogether bound by the influence of the stars, but God had so made him that he might conquer that influence, as there was something in man superior to it. The objection to astrology, that it was a useless art, as knowledge of the future was undesirable, would only hold good if it were impossible to resist the influence of the stars; but being forewarned, we might try to avert the threatening evils, and in this way astrology was of great use.
In conclusion, Tycho stated that as the doctrine of the primum mobile (spherical astronomy) was very easy, and was frequently lectured on in the University, he had thought it more advisable to take for his subject the motions of secundum mobile, explain the method of calculating the motions of the seven planets by the Prutenic tables, which were the most accurate ones, and describe the circles by means of which the tables had been computed.
Early in 1575 these lectures were finished, and Tycho Brahe shortly afterwards started on the long-deferred journey. Leaving his family at home until he had decided where he would finally settle down, he went first to Cassel to make the acquaintance of the distinguished astronomer, Landgrave Wilhelm IV. of Hesse. Wilhelm was born in 1532, and was the son of Landgrave Philip the Magnanimous, one of the most determined champions of the Reformation, who, after the disastrous battle of Mühlberg (1547), had surrendered to the Emperor, and had been kept a close prisoner for five years, during which anxious time his dominions had been governed by Wilhelm. When Philip became free in 1552, Wilhelm gladly turned back to the learned occupations, to which he had already for some years been devoted. By accident he came across the curious work of Peter Apianus, Astronomicum Cæsareum, in which the orbits of the planets are represented by movable circles of cardboard, and he became so much interested in the subject, that he had circles of copper made for the same purpose. Having afterwards studied Purbach's planetary theory and the other principal works of the time, he became, like Tycho, convinced of the necessity of making systematic observations, as he found considerable errors in the existing star catalogues. In 1561 he built a tower on the Zwehrer Thor at Cassel, of which the top could be turned round to any part of the sky, and here he observed regularly up to 1567, when the death of his father and his own consequent accession to the government of his dominions gave him less leisure for scientific occupations. As yet he had not any astronomer to assist him, and the work at his observatory had for a long time made little or no progress, when Tycho Brahe arrived at Cassel in the beginning of April 1575. The Landgrave was well pleased to receive the young astronomer as his guest, and they conversed by day about their favourite science, and observed the heavens by night together, the Landgrave with his own quadrants and unwieldy torqueta, Tycho with some portable instruments, among which was probably his sextant. Among other observations they determined the position of Spica Virginis. Naturally they discussed the nature and position of the new star, and the Landgrave told Tycho how he had once been so intent on determining the greatest altitude of the star, that he had not even desisted when he was told that part of the house was on fire, but had calmly finished the observation before leaving the observatory. Tycho was also interested to learn that the Landgrave had remarked how the motion of the sun became retarded when it approached the horizon at sunset, which might be seen by watching a sun-dial. Tycho recollected having read the same in the observations of Bernhard Walther (before whom, however, Alhazen had recognised in this phenomenon an effect of refraction), and he determined to follow up the matter by-and-by, so as to be able to correct observations made at low altitudes for refraction.
More than a week had elapsed in thus exchanging ideas and opinions, when a little daughter of the Landgrave died, and Tycho, who did not wish to intrude his company on the afflicted father, took his departure. He never saw the Landgrave again, but the visit of the young enthusiast had renewed the wavering scientific ardour of his host, and the friendship thus commenced was revived in after-years by frequent correspondence and the interchange of observations.
From Cassel, Tycho went to Frankfurt-on-the-Main, where he purchased some books at the half-yearly mart, particularly some of the numerous pamphlets on the new star. He went thence to Basle, where he had already spent some time in the winter of 1568–69, and where he now found his stay so agreeable that he thought seriously of settling down there. The University of Basle was one of the most important centres of learning in Europe, and Tycho might hope to find the same refined tastes and culture among the scientific men living there which, some sixty years before, had decided Erasmus to take up his residence at Basle. The central situation of the city, between Germany and France and not far from Italy, seemed also very convenient. Deferring, however, for the present the final step of returning home for his family, Tycho went through Switzerland to Venice, and spent some days there, after which he retraced his steps back to Germany, and went in the first instance to Augsburg. The friendships with the brothers Hainzel and Hieronimus Wolf formed during his former visit had in the meantime not been forgotten, and several letters had been exchanged between them. Thus, Paul Hainzel had in March 1574 written to express his warmest thanks for a copy of Tycho's book on the new star, and in March 1575 both he and Wolf had written to tell Tycho that they had succeeded in procuring for him from Schreckenfuchs of Freiburg a zodiacal sphere constructed according to the description of Ptolemy as formulated by Copernicus. The money sent by Tycho had been stolen by the carrier, who had never since been heard of, but the instrument had now arrived, and would be forwarded. Tycho can hardly have received these letters before starting from home, and was therefore possibly still ignorant of another piece of news contained in them, namely, that the great quadrant at Göggingen, which he had designed six years before, had in the previous December been blown down and destroyed in a great storm. The great globe which he had ordered to be made during his former visit was now nearly completed, and was the following year brought to Denmark with great trouble. At Augsburg, Tycho on this occasion made the acquaintance of a painter, Tobias Gemperlin, and induced him to go to Denmark, where he afterwards painted a number of pictures for Uraniborg and the royal castles.
At Ratisbon great numbers of princes and nobles from all parts of the empire were just then gathering to witness the coronation as King of the Romans of Rudolph the Second, King of Hungary and Bohemia, on the 1st November. Tycho also betook himself thither in the hope of meeting the Landgrave, and perhaps some other scientific men. He was, however, disappointed as to the Landgrave, who did not appear; but he had the consolation of meeting, among others, the physician-in-ordinary to the Emperor, Thaddæus Hagecius or Hayek, a Bohemian, whose name we have already met with among the writers on the new star. He gave Tycho a copy of a letter he had received from Hieronimus Munosius of Valencia on this subject, and Tycho tried in vain to dissuade him from publishing an answer to the scurrilous and absurd assertions of Raimundus of Verona. Another and most precious gift which Hagecius bestowed on Tycho on this occasion was a copy of a MS. by Copernicus, De Hypothesibus Motuum Cœlestium Commentariolus, an account of the new system of the world, which its author had written for circulation among friends some ten years before the publication of his book, De Revolutionibus, but which had never been printed. In after years Tycho communicated copies of this literary relic to various German astronomers. Probably he presented to Hagecius in return a copy of his own paper on the star, as the latter is quoted in Hagecius' reply to Raimundus.
From Ratisbon Tycho returned home viâ Saalfeld and Wittenberg. At the former place he visited Erasmus Reinhold, the younger, a son of the author of the "Prutenic Tables," who showed him his father's manuscripts, among which were extended tables of the equations of centre of the planets for every 10' of the anomaly. At Wittenberg he inspected the wooden triquetrum with which Wolfgang Schuler and Johannes Prætorius had observed the new star.
About the end of the year Tycho returned home, apparently intending very soon to leave his native land for ever in order to reside at Basle. He had, however, not yet confided his intentions to anybody, but luckily King Frederick II. had his attention specially drawn to Tycho through an embassy to Landgrave Wilhelm, which happened to return to Denmark from Cassel about that time. The Landgrave had requested the members of the embassy to urge the king to do something for Tycho, so as to enable him to devote himself to his astronomical studies at home; as these would do much credit to his king and country, and be of great value for the advancement of science. When Tycho paid his respects to the king, the latter offered him various castles for a residence, but Tycho declined these offers. King Frederick was, however, fond of learning, and anxious to retain in the kingdom so promising a man; and he shortly afterwards sent off a messenger with orders to travel day and night, until he could deliver into Tycho's own hands the letter of which he was the bearer. On the 11th of February, early in the morning, as Tycho was lying in bed at Knudstrup, turning over in his mind his plan of emigrating, the royal messenger, a youth of noble family and a connection of Tycho's, was announced, and was at once brought to his bedside to deliver the king's letter. In this Tycho was commanded immediately to come over to Seeland to wait on the king. He started the same day, and arrived in the evening at the king's hunting-lodge at Ibstrup, near Copenhagen. The king now told him that one of his courtiers had understood from Tycho's uncle, Sten Bille, that Tycho was thinking of returning to Germany, and asked him whether he had perhaps refused to accept a royal castle because he feared to be disturbed in his studies by affairs of court and state. The king next told him how he had lately been at Elsinore, where he was building the castle of Kronborg, and that his eye had fallen on the little island of Hveen, situated in the Sound, between Elsinore and Landskrona in Scania, and that it had occurred to him that this lonely little spot, which had not been granted in fee to any nobleman, might be a suitable residence for the astronomer, where he might live perfectly undisturbed; adding, that he believed he had heard from Sten Bille before Tycho went to Germany that he liked the situation. The king offered him the island and promised to supply him with means to build a house there. He finally told Tycho to think the matter over for a few days, and give his final answer at the castle of Frederiksborg; if he accepted the offer, the king would immediately give the necessary orders for payment of a sum of money for the building.
Having returned home, Tycho at once wrote a long letter to his friend Pratensis, telling him in detail all that had happened, and confessing his former intention of leaving Denmark. He asked Pratensis to show the letter only to Dancey, and requested them both to advise him in the matter. They both strongly urged him to accept the king's offer, which he accordingly did, and already on the 18th of February the king by letter granted Tycho "five hundred good old daler" annually until further orders. Four days after, on the 22nd February 1576, Tycho paid his first visit (at least as far as we know) to the little island which was destined to become famous through him, and the same evening took his first observation there of a conjunction of Mars and the moon. If he could have foreseen that he was destined to furnish the means of circumventing the tricks of the inobservable Sidus (as Pliny called Mars), and himself to add more to our knowledge of the moon's motion than any one had done since Ptolemy, he would certainly by this coincidence have been confirmed in his belief in astrology. On the 23rd May a document was signed by the king of which the following is an exact translation:—
"We, Frederick the Second, &c., make known to all men, that we of our special favour and grace have conferred and granted in fee, and now by this our open letter confer and grant in fee, to our beloved Tyge Brahe, Otte's son, of Knudstrup, our man and servant, our land of Hveen, with all our and the crown's tenants and servants who thereon live, with all rent and duty which comes from that, and is
given to us and to the crown, to have, enjoy, use and hold, quit and free, without any rent, all the days of his life, and as long as he lives and likes to continue and follow his studia mathematices, but so that he shall keep the tenants who live there under law and right, and injure none of them against the law or by any new impost or other unusual tax, and in all ways be faithful to us and the kingdom, and attend to our welfare in every way and guard against and prevent danger and injury to the kingdom. Actum Frederiksborg the 23rd day of May, anno 1576. "Frederick."
The same day the chief of the exchequer, Christopher Valkendorf, was instructed to pay to Tycho Brahe 400 daler towards building a house on the island of Hveen, for which Tycho was himself to provide building materials. This money was paid on the 27th May. Just at the moment when everything was settled and Tycho's prospects in life were most brilliant, he had the grief to lose his friend Johannes Pratensis, who died suddenly on the 1st June from a bleeding of the lungs while lecturing in the University. He was only thirty-three years of age, and had been professor of medicine since 1571. Tycho had promised to write a Latin epitaph over his friend in case he should survive him, and he had it printed in 1584 at his own printing office at Uraniborg. He also caused a monument to be erected to the memory of Pratensis in the Cathedral of Copenhagen.
- Danske Magazin, ii. p. 192 (Weistritz, ii. p. 70). The English traveller, Fynes Moryson, tells us that Tycho was said "to liue vnmarried, but keeping a Concubine, of whom he had many children, & the reason of his so liuing was thought to be this; because his nose hauing been cut off in a quarrell, when he studied in a Vniversity of Germany, he knew himselfe thereby disabled to marry any Gentlewoman of his own quality. It was also said that the Gentlemen lesse respected him for liuing in that sort, and did not acknowledge his sonnes for Gentlemen." Moryson heard this at Elsinore in 1593; see his "Itinerary of his ten Yeeres Travell through the twelve Domjnions of Germany, Bohmerland, &c." London, 1617, p. 59.
- By the Danske Lov of 1683 and the Church ritual of 1685. See an article in the Historisk Tidsskrift, fifth series, vol. i. 1879, by the Danish Minister of Justice, J. Nellemann.
- Early in the sixteenth century a Danish nobleman, Mogens Lövenbalk, brought a young Scotch lady, Janet Craigengelt (on the female side said to have been related to the Grahams of Montrose), home to his castle, Tjele, in Jutland, where she lived for many years and bore him two children. Her son tried in vain to obtain recognition as his father's legitimate heir, and his claims were set aside chiefly because his mother had clearly not been treated as the mistress of the house, but rather as a dependent. On the other hand, the University of Wittenberg declared in favour of the legitimate birth of the children, evidently guided by the then ruling principle of canonical law, that a long intercourse with all the outer resemblance of wedlock had the same legal weight as a formal marriage.
- The eldest daughter was buried in Helsingborg church. In the epitaph she is called filiola naturalis, which has made Langebek doubt whether she had the same mother as the other children (D. Magazin, ii. p. 194); but this very expression, which originated in the Roman jurisprudence, shows that the humble companion of Tycho's life was her mother (see Gibbon's Decline and Fall of the Roman Empire, chapter xliv.).
- He had also observed at Copenhagen on the 24th April. Nearly all these observations are distance-measures of planets from fixed stars, doubtless with the sextant, "satis exquisite, subtracta instrumenti parallax!;" but a small quadrant is also mentioned.
- "Tychonis Brahei de Disciplinis mathematicis oratio publice recitata in Academia Haffniensi anno 1574, et nunc primum edita . . . studio et opera Cunradi Aslaci Bergensis. Hafniæ, 1610, 4to." Dedicated to Tycho's brother, Sten Brahe of Knudstrup, and the editor has added some of his own speeches. Second edition, Hamburg, 1621, to the title is added "in qua simul Astrologia defenditur et ab objectionibus dissentientium vindicatur. Cum Præloquio Joach. Curtii." Both editions are very scarce.
- "Habent se enim stellæ fixæ in coelo veluti matres, quæ nisi a septem errantibus stellis stimulentur et impregnentur, steriles sunt et nihil in hac inferiori natura progignunt" (Oratio, p. 20).
- Shortly before starting he had occasion to show his friendship for his former tutor Vedel and his patriotism. Vedel was just in the act of finishing his translation of the Danish Chronicle of Saxo Grammaticus (from the end of the twelfth century), but the cost. of the paper necessary for so large a work was so great, that Vedel's friends feared that the work might remain unprinted. Tycho wrote a Latin poem to encourage his friend, calling on the Danish women to sacrifice some of their linen, and to send it to the papermill in Scania, lest the deeds of their ancestors should be buried in oblivion (Wegener's Life of Vedel, p. 83).
- Tychonis Epist. Astron., Dedication. In his Progymn., p. 616, Tycho states that the Landgrave on this occasion gave him a copy of his own catalogue of improved star-places. Tycho prints as specimens the places of Aldebaran, Betelgeux, and Sirius; but though superior to the positions given by Alphonsus and Copernicus, those of the Landgrave were as yet very inferior to Tycho's. We shall, farther on, see how the observations made at Cassel afterwards became much more accurate than they were at the time of Tycho's visit.
- Gassendi, p. 29.
- Astr. Inst. Mechanica, fol. G. 2.
- Erasmus Oswald Schreckenfuchs (1511–1579), Professor of Mathematics, Rhetorics, and Hebrew, first at Tübingen, afterwards at Freiburg in Breisgau; editor of the works of Ptolemy (Basle, 1551), and author of commentaries on the writings of Sacrobosco, Purbach, and Regiomontanus.
- By Petrus Aurifaber, "cum supellectile sua" (Was he the maker of the globe?) These letters are published in T. Brahe et ad eum doct. vir. Epist., pp. 11 seq. Whether Tycho ever got the sphere is not known.
- It may have been re-erected later, as Joh. Major wrote to Tycho Brahe in 1577 that it was still in use; but, on the other hand, P. Hainzel wrote in 1579 that he had not observed the comet of 1577 for want of convenient instruments (T. B. et doct. vir. Epist., pp. 42 and 46).
- Progymn., pp. 567 and 734; see also above, p. 64.
- Progymn., p. 479. Though the description there given of the MS. ought to have attracted attention, and have led to a search for copies of it, the Commentariolus remained perfectly unknown till the year 1878, when it was noticed that there was a copy of it in the Hof-Bibliothek at Vienna, and immediately afterwards another copy was found at the Stockholm Observatory. The Vienna MS. had been presented by Longomontanus on his departure from Prague in 1600 to another of Tycho Brahe's disciples, Joh. Eriksen, and it is therefore doubtless a copy of the MS. belonging to Tycho. See Prowe, Nicolaus Coppernicus, i. part ii. p. 286.
- Danske Magazin, ii. p. 196, quotes Thomasini Elog. Viror. Illustr., according to which, Tycho, in his younger days, received an offer of an appointment at the Emperor's court. There is no confirmation anywhere of this statement; but if the offer was ever made, it was probably done at Ratisbon in 1575.
- Progymn., p. 699.
- Progymn., p. 636 ; see also above, p. 58.
- Epist. Astron., Dedication, fol. 2.
- Afterwards called Jaegersborg, about five English miles north of Copenhagen; it was demolished long ago. The present king's summer residence, Bernstorff, is close to the place.
- T. B. et Doct. Vir. Epist., p. 21 et seq. In the letter of February 14, Tycho asks Pratensis to tear up or burn the letter as soon as Dancey had seen it, and in his reply next day, Pratensis writes that he had destroyed it. Tycho must therefore have kept a copy.
- About £114, but of course this represented at that time a much greater sum. In Denmark the first Joachimsthaler had been coined in 1523, exactly of the same value as those first issued in North Germany in 1519, which value the Danish daler retained nearly unaltered, though the name changed, first to species (from in specie, or in one piece), then to rigsdaler species. The coinage had greatly deteriorated during the war with Sweden, hence doubtless the expression "good old daler."
- Februarii die 22. Existente in M. C. ultima in capite Hydræ quæ est versus ortum, et sola juxta collum, apparebat visibilis conjunctio ☾ et ♂ admodum partilis, adeo ut ☾ inferiore et meridionaliore cornu fere attingeret corpus ♂ distans saltem ab eo parte sexta sui diametri accipiendo distantiam hanc ab inferiori cornu limbi. Erat autem circa idem tempus per observationem alt. lucidiss. in pede Orionis ii g. 20 m.—H. 9 M. 30. Infimus vero ☾ limbus circa quem ♂ conspiciebatur elevari visus est 10 g. 50 m. Observatio hæc facta i. Huennæ. Langebek in Danske Mag., ii. p. 194 (Weistritz, ii. p. 73), refers to this visit to Hveen as made in the year 1574. In the original the year is not given, and the observation follows after one of May 19, 1574. But on February 22, 1574, the moon was only a few days old, and Mars was at the other side of the heavens, while they were very close together on the same date in 1576.
- Danske Magazin, ii. p. 198.
- Friis, Tyge Brahe, p. 58.
- The epitaph is reprinted in Danske Magazin, p. 199 (Weistritz, ii. 84), and in T. B. et ad eum Doct. Vir. Epist., p. 28.