Page:Popular Science Monthly Volume 51.djvu/699

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THE DISCOVERY OF THE SUN SPOTS.
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of his father, David Fabricius. The claim of priority having been already settled by Humboldt, the secondary object is really the more important one. A little-known paper of Jean Fabricius on sun spots and their apparent turning with the sun, published at Wittenberg in 1611, is reproduced in the book; and after it a wholly unknown astrological paper by David Fabricius on the appearance of the new star in Ophiucus, which Kepler's pupil, Jean Brunowski, discovered on the 10th of December, 1604. David Fabricius saw this star for the first time December 13, 1604, or only three days after Brunowski, of whose discovery he certainly knew nothing, and wrote two other notices of it, which are lost. The frontispiece of David Fabricius's Prognosticon astronomicum is also given, with a complete list of the author's writings, including those which are lost. Of these, the Prognostica for 1607 and 1616 have recently been found at Darmstadt and Nuremberg. From a few facts concerning the life of David Fabricius gleaned from the Prognosticon for 1617, it appears that he was born at Essen, in East Friesland, March 9, 1564, and died—killed with a spade by a peasant of his commune—May 7, 1617. He assumed the ecclesiastical dress at an early age, and performed the offices of a court pastor, while he also devoted himself to astronomical studies, and was the first to announce that Omicron or Mira Ceti, was a variable star.[1] He made this discovery August 13, 1596, and on the same day remarked a star of the third magnitude, red like Mars, and situated in 25° 47′ and 15° 45′ south of the ecliptic. Twelve years passed without his seeing it only very indistinctly, and he did not find it again clearly till 1609. The author observes that the astrological intimations of David Fabricius did not prevent his being a good astronomer of the second rank, like Longomontanus, Scheiner, and Simon Marius. His correspondence with Kepler proves that he furnished him with important material for the composition of his works.

Jean Fabricius, the eldest of seven sons, was born at Resterhave, near Dornum, in East Friesland, January 18, 1587. The Calendarium historicum of David Fabricius gives some facts concerning his life. He attended the university at Helmstadt as a medical student in 1605, at Wittenberg in the next year, whence he passed to Leyden, where he was registered as a student of medicine in 1609. Omitting certain statements concerning his astrological and meteorological studies, we remark that the publication of the work to which he owes his fame in astronomy dates from the time of his doctorate in philosophy at Wittenberg,


  1. The period of the variability of this star was determined by Jean Holward, forty-two years afterward.