Page:Popular Science Monthly Volume 65.djvu/129

Rh So far as I know, this is the only evidence for the belief of Copernicus in astrology. We have no horoscopes from his hand but, like all his contemporaries, he probably gave it a place among the sciences.

Rheticus deserves the gratitude of all calculators for his table of trigonometric functions (sines, tangents, secants) to ten decimal places, for every 10″ of the quadrant, published in a huge volume by his pupil, Otho, under the title 'Opus Palatinum de Triangulis.' The tables of Rheticus are the basis upon which Vlacq founded his great tables, and they have served as models for many followers. Lansberg's tables appeared fifteen years after the 'Opus Palatinum' and lightened the immense labors of Kepler.

Toward the end of the year 1541 Rheticus returned to Wittenberg carrying with him a part of Copernicus 's manuscript—a treatise on 'Trigonometry'—which he printed in 1542. The complete manuscript of the 'De Revolutionibus' was sent by Copernicus to his old friend Giese, the bishop of Culm, for such disposition as he thought best. The bishop sent it to Rheticus to arrange for its printing at Nuremberg, and to see it through the press. It fell out that the printing had to be confided to Andreas Osiander, a Lutheran minister interested in astronomy. The book was published early in 1543, and a copy reached Copernicus on May 24, the very day of his death.

Osiander prefixed to the volume an introductory note which he did not sign, as follows:

Scholars will be surprised by the novelty of the hypothesis proposed in this book, which supposes the earth to be in motion about the sun, itself fixed. But if they will look closer they will see that the author is in no wise to be blamed. The aim of astronomy is to observe the heavenly bodies and to discover the laws of their motions; the veritable causes of the motions it is impossible to assign. It is consequently permissible to imagine causes, arbitrarily, under the sole condition that they should represent, geometrically, the state of the heavens, and it is not necessary that such hypotheses should be true, or even probable. It is sufficient that they should furnish positions that agree with observations. If astronomy admits principles, it is not for the purpose of affirming their truth, but to give a certain basis for calculation.

The best authorities affirm that Osiander 's apology, which he had suggested to Copernicus as early as 1540, was unauthorized.

Osiander made many changes in the text also, and added the last two words of the title under which the book was printed—' De Revolutionibus Orbium Cœlestium. ' Readers of our day universally interpret the apology to be an attempt to forestall theological opposition and persecution. They remember the conflict of Galileo with the church. But Osiander was a protestant divine, Copernicus a catholic priest. It is passing strange to conceive that a Lutheran schismatic should intervene to shield an orthodox catholic from accusations of heresy. Moreover, Copernicus had good reasons for believing that the princes of the