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CHAPTER 1
INTRODUCTION
NICOLAUS COPERNICUS
Nicolaus Copernicus was born in 1473 at Thorn on the banks of the Vistula. His father was a prosperous merchant and municipal official in the old Hansa town. But he died when Nicolaus was only ten years old} and it was the boy's good fortune to have for maternal uncle Lucas Watzelrode, who became Bishop of Ermland in 1489. The uncle took a fatherly interest in the nephew, guiding his way and smoothing his path. While Copernicus was still a young man, Bishop Lucas designated him a canon of the Cathedral of Frauenburg. He enjoyed the income from this ecclesiastical post until his death (May 24, 1543) at the scriptural age of seventy} and before he was thirty years old, he received in addition an appointment to a sinecure at Breslau.
Copernicus had his elementary schooling in his native city and entered the University of Cracow in 1491. After several years of attendance at the renowned Polish center of learning, he journeyed to Italy in 1496. At Bologna and Padua he studied the liberal arts, medicine, and law, obtaining the doctor's degree in canon law at Ferrara in 1503.
Shortly after his return from Italy his first published work appeared from the press, a translation of an inferior Greek epistolographer into Latin. But it was not only in this concern with classical antiquity that Copernicus showed himself a man of the Renaissance. He also strove to achieve the many-sided accomplishments of that humanistic ideal, the universal man. He was competent in canon law; he practiced medicine; he wrote a tract on coinage; he served his cathedral chapter as an administrator and diplomatic representative; he painted his own portrait; he made many of his own astronomical instruments; and he established the heliocentric system on a firm basis.
Germans and Poles have bitterly disputed the question of Copernicus's ethnic origin, each national group claiming the distinguished astronomer for its own. Where does the truth lie in this controversy? Politically, Copernicus was a subject of the king of Poland} he remained loyal to the Roman Catholic church} and he wrote chiefly in Latin, but a few of his private letters were composed in German.
GEORGE JOACHIM RHETICUS
George Joachim was born on February 16, 1514, at Feldkirch in the ancient Roman province of Rhaetia. In conformity with the strong classical tradition of his day he assumed the surname "Rheticus." He was apparently reared in comfortable circumstances, for his parents took him in his youth to Italy.
After studying at Zürich, in 1532 he entered the University of Wittenberg, where he obtained his degree. He continued his studies at Nuremberg and Tübingen and then received an appointment as professor of mathematics at Wittenberg. He began his teaching during the academic year 1536–37.
Reports concerning Copernicus's innovations in astronomy had reached the young man, and he was filled with great eagerness to become acquainted with the new system. But how was he to do this? Copernicus had published nothing. Rheticus resolved to seek out the aged scholar at Frauenburg and to master the new astronomy at its source.
Accordingly he set out for Prussia in the spring of 1539. Copernicus received him cordially and was his host for more than two years despite religious difficulties. Rheticus came from the principal stronghold of Protestantism, and there was bitter anti-Lutheran feeling in official Ermland. In this atmosphere of religious animosity the Protestant professor lived with the Catholic canon and studied his system with enthusiasm.
But Rheticus did not confine his studies to astronomy. On the basis of extensive travel during his stay in Prussia, he prepared a map of the region. Though the map has not been preserved, an accompanying essay on the methods of drawing maps is extant. Two other works written during this period have both disappeared. The one was devoted to proving that the new astronomy did not contradict Scripture; the other was a biography of Copernicus. The loss of the latter is particularly unfortunate, for an account written by one so close to the great astronomer would undoubtedly throw valuable light on many obscurities in the life of Copernicus.
Rheticus left Prussia at the end of September, 1541. He returned to Wittenberg, resumed his teaching, and served as dean of the arts faculty in the early months of 1542. He also supervised the separate printing of the trigonometrical portion of Copernicus's De revolutionibus orbium caelestium.
He left Wittenberg in 1542 and went to Nuremberg, where the great work was being printed. The early sections were set up under his supervision; but after his departure for Leipzig his place was taken by Andreas Osiander, of whom we shall hear more below.
Rheticus taught at the University of Leipzig from 1542 to 1551. Before he resigned, he published an ephemeris for 1551. After his resignation he devoted himself principally to the calculation of an extensive set of trigonometric tables, for which he has an independent place in the history of mathematics. In this work he received welcome financial assistance from the Emperor Maximilian II and several Hungarian nobles.
It is a curious circumstance that Rheticus was requited for the support and encouragement he brought to the old age of Copernicus. The closing years of his own life were brightened by the interest taken in his project by a young man, Lucius Valentine Otho. The tables on which he worked for a quarter of a century were finally printed in 1596, twenty years after his death, as the Opus palatinum de triangulis, begun by George Joachim Rheticus and completed by L. Valentine Otho.
THE COMMENTARIOLUS
Some years before Copernicus consented to the publication of his large work De revolutionibus orbium caelestium, he wrote a brief sketch (commentariolus) of his astronomical system. The Commentariolus was not printed during the life of its author} but a number of handwritten copies circulated for a time among students of the science, and then disappeared from view for three centuries. A copy found in Vienna was published by Maximilian Curtze in 1878. A second copy found in Stockholm was published in 1881. On Curtze's collation of these two manuscripts Leopold Prowe based the text from which the present translation was made. A third manuscript is believed to exist in Leningrad} so far as I know, it has never been published.
The opening section of the Commentariolus was translated by Prowe. L. A. Birkenmajer published a partial translation of the work into Polish. The only complete translation previous to the present one was done in German by Adolf Müller.
The date of composition of the Commentariolus cannot be precisely determined. But an examination of its contents shows conclusively that the Commentariolus expounds a heliocentric system which differs in several essential features from the system taught by the mature Copernicus in the De revolutionibus. The earlier view may be called "concentrobiepicyclic," and the later "eccentrepicyclic"; the meaning of these terms will be made clear later on. To Ludwik Birkenmajer must be assigned the credit for first pointing out that the two systems are independent, or rather that the Commentariolus is a first stage in the development of the heliocentric theory in the mind of Copernicus.
THE LETTER AGAINST WERNER
John Werner, a figure of some importance in the history of mathematics, published in 1522 at Nuremberg a collection of papers on mathematics and astronomy. One of these, the De motu octavae sphaerae tractatus primus, was sent to Copernicus by Bernard Wapowski, who had been his fellow student at the University of Cracow and was now a canon at Cracow and secretary to the king of Poland. Wapowski requested Copernicus to pass judgment on Werner's contentions. Copernicus complied, sending to Wapowski under date of June 3, 1524, the Letter against Werner, a vigorous attack upon Werner's position. In an age when scientific periodicals had not yet come into existence, such letters served the function now performed by articles and extended book reviews. The Letter against Werner, taken together with the Commentariolus, may be said to constitute the minor astronomical works of Copernicus -y for besides the De revolutionibus we have nothing else on astronomy from his pen.
Handwritten copies of the Letter against Werner circulated for a time; and from a copy preserved in Berlin the first printed edition was made. It was included in Jan Baranowski's edition of the De revolutionibus. Although the text of this edition was obviously faulty, it was reproduced by Hipler and Prowe. Then Maximilian Curtze found a second manuscript of the Letter against Werner in Vienna; he collated both manuscripts and published a critical text.
The present translation was made from Curtze's text. So far as I know, there have been two earlier translations, both into Polish, and both on the basis of the Berlin manuscript alone.
THE NARRATIO PRIMA
It will be recalled that Rheticus left the University of Wittenberg in the spring of 1539 and set out for Prussia to study with Copernicus. In the middle of May he reached Posen, and from there he sent a letter to John Schöner, with whom he had studied at Nuremberg. In this letter he promised to inform Schöner as soon as possible whether the achievement of Copernicus justified his reputation.
Within a short time after his arrival Rheticus became aware that his host was a genius of the first rank. But Copernicus, for reasons which will be stated below, was reluctant to publish his astronomical work. The young professor added his voice to the chorus of friends who were urging Copernicus to release his manuscript for publication. In order to test public reaction to the innovations introduced by Copernicus, Rheticus rapidly wrote a survey of the principal features of the new astronomy. He cast it in the shape of a letter to his former teacher Schöner and had it printed at Danzig in 1540.
The response was so favorable that a second edition of the Narratio prima was brought out in 1541 at Basel. It is altogether likely that the welcome accorded to the Narratio prima was the clinching argument that finally persuaded Copernicus to put his manuscript into the hands of a printer.
The reader of the Narratio prima (First Account) will notice that Rheticus speaks of his intention to compose a "Second Account" ("Narratio secunda," "Narratio altera"). But Rheticus never wrote the "Second Account." The Narratio prima was important, for it was the only book to which astronomers could turn for information about Copernicus's system. But by preparing the way for the publication in 1543 of Copernicus's own work, the De revolutionibus orbium caelestium, it made any "Second Account" superfluous.
When the second edition of the De revolutionibus appeared in 1566 at Basel, it included the Narratio prima. Rheticus's work was printed a fourth and a fifth time as a companion piece to Kepler's Mysterium cosmographicum (Tübingen, 15963 Frankfurt, 1621). It received its sixth printing in the Warsaw edition (1854) of the De revolutionibus and its seventh in the Thorn edition (1873). Finally Pro we printed it for the eighth time. The present translation was made from Prowe's text.
The Warsaw edition included a translation into Polish, which is, so far as I know, the only one previous to the present.
THE DOCTRINE OF THE SPHERES
The ancient Greek astronomer Eudoxus (about 408-355 B.C.) introduced imaginary spheres into astronomical theory for the purpose of representing the apparent motions of the planets. These spheres were invisible, and the observable planet was regarded as situated, like a spot or point, on the surface of the invisible sphere. The planet was deemed to have no motion of its own, but simply to participate in the motion of the sphere to whose surface it was attached. Now the observed movements of any planet are so complicated that a single sphere, moving at a uniform rate always in the same direction, could not produce the observed phenomena. Hence it became necessary to devise for each planet a set of spheres. These remained an integral part of astronomical theory until Kepler (1571-1630) banished them by demonstrating the ellipticity of the planetary orbits.
Copernicus used these spheres (orbes) throughout his work. He avoided taking sides in the controversy over the question whether the spheres were imaginary or real, whether, that is, they were simply a mathematical means of representing the planetary motions and a convenient geometrical basis for computing the apparent paths, or whether they really had a physical existence in space and like a piece of machinery produced the observed phenomena. But whether the planets were carried by material balls or hoops or by imaginary spheres or circles through a medium of whatever type, the resultant computation of the actual planetary courses was the same. From Copernicus's language it sometimes appears that he regarded the planet as attached to a three-dimensional sphere; but more often a two-dimensional great circle of the sphere was the geometrical figure to which he affixed the planet. For astronomical, as opposed to cosmological or astrophysical, theory it was a matter of indifference whether a planet was thought to be attached to a sphere or to a great circle thereof.
This repeated shift from sphere to circle and back again is, I believe, the root of some troublesome difficulties in Copernicus's terminology. Consider first the ambiguity of the word orbis, a term of central importance and frequent occurrence in his writings. Now orbis may mean either a three-dimensional sphere or a two-dimensional circle; and in fact it is constantly used by Copernicus in both senses, being interchangeable at times with sphaera and more frequently with circulus.
An example of equivalence between orbis and sphaera occurs in the first Assumption of the Commentariolus: Omnium orbium caelestium sive sphaerarum unum centrum non esse; "There is no one center of all the celestial spheres [orbium sive sphaerarum]." For a second instance of interchangeability of orbis with sphaera we turn to the section of the Commentariolus entitled "The Order of the Spheres [orbium]": Orbes caelestes hoc ordine sese complectuntur. Summus est stellarum fixarum immobilis et omnia continens et locans; "The celestial spheres [orbes] are arranged in the following order. The highest is the immovable [sphere] of the fixed stars, which contains and gives position to all things." We may properly hold that for "the sphere of the fixed stars" Copernicus wrote here stellarum fixarum orbis, while the expression he regularly employs (in the De revolutionibus) is stellarum fixarum sphaera or non errantium stellarum sphaera. These phrases do not occur anywhere else in the Commentariolus; for that paper, devoted almost entirely to planetary theory, seldom refers to the sphere of the fixed stars, and on those occasions it uses firmamentum. On the other hand, in the Letter against Werner, which is concerned exclusively with the fixed stars, their sphaera is mentioned twice. It is of interest to note that, although enormous differences in the distances of stars were demonstrated centuries ago, present-day textbooks of elementary astronomy still retain, for the purposes of preliminary exposition, the concept of an imaginary "sphere" of the fixed stars, a concept adequate enough for ordinary astronomical work.
We have seen that at times orbis means a three-dimensional sphere, sphaera. We shall next examine some passages in which orbis is equivalent to circulus, a two-dimensional circle. Following the ancient and medieval tradition, Copernicus devises for each of the planets a set of geometrical figures, designed to account as accurately as possible for the observed movements of the planet or, in the familiar phrase, "to save the appearances." These geometrical figures are regularly referred to in the Commentariolus as orbes; in fact orbis occurs there most frequently in two senses: (a) orbis magnus, the path of the earth's annual revolution about the sun; (b) the deferent of the moon, Saturn, Jupiter, Mars, Venus, and Mercury. But in the closing paragraph of the Commentariolus, where Copernicus summarizes the plan of the solar system elaborated in that paper, he refers to these same geometrical figures as circuli.
(Continues…)
Excerpted from "Three Treatises on Copernican Theory"
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Copyright © 1959 Edward Rosen.
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