John Louis Emil Dreyer

“ Under the green part of the tree a youth is seated, wearing a laurel wreath on his head and holding a star-globe and a book in his hands. Under the withered part of the tree is a table covered with money-boxes, sceptres, crowns, coats of arms, finery, goblets, dice, and cards, all of which a skeleton tries to grasp in its outstretched arms. Above is the pentameter, "Vivimus ingenio, cætera mortis erunt," pointing out the vanity of worldly things, while only earnest study confers immortality. ”

“ He even found out that Stadius had not computed his places correctly from Reinhold's tables. And already at that time, while Tycho was a youth only sixteen years of age, his eyes were opened to the great fact, which seems to us so simple to grasp, but which had escaped the attention of all European astronomers before him, that only through a steadily pursued course of observations would it be possible to obtain a better insight into the motions of the planets, and decide which system of the world was the true one. ”

“ Si Tycho fut resté dans son ile, jamais Kepler ne se fut rendu à ses invitations; nous n'aurions certainement pas la Théorie de Mars, et nous ignorerions peut-être encore le véritable système du Monde. ”

“ MURAL QUADRANT.
of Seeland and Scania in the distance, helps to form very attractive scenery, which adds to the peculiar charm the island has for any one who is interested in the great memories connected with it. One can understand why Tycho calls it "Insula Venusia, vulgo Hvenna," as if it were worthy of being called after the goddess of beauty. ”

“ 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. ”

“ Tycho could not but see that Vedel was only doing his duty, and Vedel gradually had to acknowledge that the love of astronomy had become so deeply rooted in his pupil that it was utterly impossible to force him against his will to devote himself to a study he disliked, or at least looked on with indifference. Another circumstance which was a bond of union between them was that the learned men whose society Vedel sought were to a great extent the same to whom Tycho looked for instruction. ”

“ Being thus obliged to consider the matter more fully, Kepler did so in his reply, in which his wonderful genius displays itself by the way in which he suggests that the moon might be retarded in its motion by a force emanating from the sun, which would be greatest in winter, when the moon and earth are nearer to the sun than they are in the summer. ”

“ In the ancient free city of Augsburg Tycho seems to have felt perfectly at home. Dear to all Protestants as being the place where the fearless Reformers had declared their faith, and where the Protestant princes and cities of Germany had signed the "Confession of Augsburg," the city possessed the further attraction of having many handsome public and private buildings and spacious thoroughfares, while the society of many men of cultured tastes and princely wealth (such as the celebrated Fugger family) , made it an agreeable place of residence. ”

“ 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. ”

“ Though the star was so near the equinoctial colure that it nearly touched it with its rays, it was quite within the vernal quadrant, and it announces that some great light is at hand, just as the sun when past the vernal equinox conquers the darkness of night. And as the star was visible over most of the earth, so the effects of it will be felt over the greater part of the globe, though the northern hemisphere will be especially affected. ”

“ With this instrument Tycho measured the distance of the star from the nine principal stars of Cassiopea. We can easily picture to ourselves the impatience with which he must have awaited the next clear night, in order to see whether this most unusual phenomenon would still appear, or whether the star should have vanished again as suddenly as it had revealed itself. ”

“ 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. ”

“ We have now followed Tycho through what may be considered the first period of his life. By study and intercourse with learned men he had mastered the results of the science of antiquity and the Middle Ages. But though he had to some extent already, as a youth seventeen or eighteen years of age, perceived the necessity of a vast series of systematic observations on which to found a new science, he had hitherto shrunk from carrying out this serious undertaking himself, or had perhaps despaired of getting the means of doing so. ”

“ No advance had been made in the knowledge of the moon's motion, so important for navigation, nor in the knowledge of the nature of the planetary orbits, the uniform circular motion being still thought not only the most perfect, but also the only possible one for the planets to pursue. ”

“ As Rantzov, who was a very wealthy man, had spent great sums on accumulating books and treasures of art in his various castles in Holstein and Slesvig, Tycho found at Wandsbeck (or Wandesburg, as the new castle was called) not only a comfortable dwelling, but also one in which the owner's refined tastes had created a home which might to some extent bear comparison with the one he had left for ever. ”

“ It is much to be regretted that we are utterly unacquainted with the manner in which Copernicus came to design the new system of astronomy which has made his name immortal. But he had probably early perceived that, however valuable the labours of Regiomontanus had been, they had not improved the theory of celestial motion, so that the most important problem, that of computing beforehand the positions of the planets and accounting for their apparently intricate movements, was practically untouched since the days of Ptolemy. ”

“ 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. ”

“ But, regardless of the duties imposed on him by his station, the Emperor reluctantly devoted a moment to business of any kind, while he willingly gave his time and the limited pecuniary means of his impoverished dominions to collecting art treasures and promoting science—the real science represented by Tycho and Kepler, as well as the imaginary ones taught by the disciples of Cornelius Agrippa and Cardanus. Prague, where he usually resided, was not a very favourable place for the growth of science and art, as Bohemia had never settled down since the Hussite disturbances. ”

“ Tycho remarks that an epicycle might be introduced to account for this, but as the inequality was only 5', he did not deem it necessary to go so far in refining the theory of a transient body like a comet; and besides, it is probable that comets, which only last a short time, do not move with the same regularity as the planets do. He finds the inclination of the orbit to the ecliptic equal to 29° 15', and shows how to compute the place of the comet for any given time by means of the table of its orbital motion with which he concludes the first part of the book. ”

“ Surrounded by his family and numerous pupils, many of whom came from great distances to seek knowledge in the house of the renowned astronomer and assist him in his labours, frequently honoured by visits from men of distinction both from Denmark and abroad, Tycho during these years steadily kept the object in view of accumulating a mass of observations by means of which it would be possible to effect that reform of astronomy which was so imperatively demanded, and for which the labours of Copernicus had merely paved the way. ”

“ 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. ”

“ We have already alluded to the idea of the universe as a whole, of which the single parts were in mystical mutual dependence on each other—an idea which had arisen among Oriental nations in the infancy of time, had thriven well owing to the mystical tendency of the Middle Ages, and had been gradually developed and formed into a complicated system by the speculations of philosophers of successive periods. ”

“ The German Emperor, Rudolph the Second, whose service Tycho Brahe was now about to enter, was a man deeply interested in science and art, personally of a most amiable disposition, but most singularly unfit for the exalted and difficult position he had to fill. ”

“ 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. ”

“ In the meantime the plague had appeared at Rostock, but Tycho still lingered there, awaiting the reply to his letter to the king. If, before he took the decisive step of removing his family, his great treasure of observations, and nearly all his instruments out of the Danish dominions, Tycho had addressed himself to the king, who was of an open, generous nature, it is not unlikely that he might have been treated very differently ”

“ The astrological significance of the comet Tycho does not trouble himself about, though he takes the opportunity of stating that he does not consider astrology a delusive science, when it is kept within bounds and not abused by ignorant people. For the sun, moon, and fixed stars would have sufficed for dividing time and adorning the heavens, and the planets must have been created for some purpose, which is that of forecasting the future. ”

“ 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 needless to say that the accuracy cannot be so great as Tycho fondly hoped, as the errors of observation would be increased by neglect of refraction and by his ignorance of the existence of aberration and nutation. ”

“ The dependence of vegetable life on the motion of the sun in the ecliptic, and the similarity of the period of the moon's orbital motion to that of certain phenomena of human life, were looked upon as proofs of the connection between the sublunary and the æthereal worlds; and as the human body was composed of the elements, it would, like these, be influenced by the forces, chiefly the planets, by which the celestial part of the kosmos exercised its power. ”

“ In 1601 Kepler also occupied himself with the theories of Mercury, Venus, and Mars, and noticed that it was not possible to represent the apparent motion of the planets by assuming for the orbit of the sun (or the earth) a simple excentric circle with uniform motion, as had always hitherto been done, but that it would be necessary to have recourse to an equant as in the planetary theories of Ptolemy. When Kepler asked Tycho if he would not mention this in the Progymnasmata, he declined to do so, as it would take time to investigate the equal motion, and he wanted the book published at once. ”

“ The time when he will be inclined to marry will be about the age of twenty or twenty-one, when Venus comes in sextile aspect with Jupiter about the medium cœli, or in his thirty-fourth or thirty-fifth year, or, if not married before, in his forty-seventh year, when the moon reaches the seventh house. But all this depends more on man's free will than on the stars. ”

“ In order to keep their power as long as possible, it was decided that the minority should last till the Prince was twenty years of age. The quiet and careful education of the young King- Elect, which his father had planned, was continued, and the Government of the Protectors was on the whole well and ably conducted. To Tycho Brahe it was of great importance that the Chancellor Kaas was a member of the Government, as the precarious tenure by which he held all his endowments and pensions made it a vital matter for him to have firm friends among those at the head of affairs. ”

“ Of a star to be determined, the declination was measured directly by the armillæ or a meridian quadrant, and the distance from a known star was measured with a sextant. This furnished, as before, a spherical triangle, with the three sides known, from which the angle at the pole or the difference of right ascension could be computed. Generally the star was connected with two known stars, one preceding and one following it, which gave two results for the right ascension as a control. Tycho communicates twelve examples of this double determination, the results always agreeing within a minute. ”