THE DISCOVERY OF THE SUN SPOTS. 683 



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 Fabricms 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 as- 

 tronomicum is also given, with a complete list of the author's 

 writings, including those which are lost. Of these, the Prog- 

 nostica 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 Prognoslicon 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 him- 

 self to astronomical studies, and was the first to announce that 

 Omicron or Mira Ceti, was a variable star.* He made this dis- 

 covery 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 see- 

 ing 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 fur- 

 nished him with important material for the composition of his 

 works. 



Jean Fabricms, the eldest of seven sons, was born at Rester- 

 have, 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 publi- 

 cation of the work to which he owes his fame in astronomy dates 

 from the time of his doctorate in philosophy at Wittenberg, 



* The period of the variability of this star was determined by Jean Holward, forty-two 

 years afterward. 



