684 POPULAR SCIENCE MONTHLY. 



whither he returned after his sojourn at Leyden. The telescope 

 was discovered in Holland in 1608 by the optician Jean Lipper- 

 sheim, of Middelbourg, who immediately applied to the States 

 General for a patent. Jean Fabricius learned of the discovery at 

 Leyden, and took the instrument to Osteel, where his father was, 

 and with it found the sun spots. Nothing is known of him after 

 the publication of the book on the sun spots already mentioned 

 (1611), except that he practiced medicine at Marienhave, near Os- 

 teel, and died there probably about 1617. If the Prognosticon for 

 1618 had not been lost, we should doubtless have had some details 

 respecting his death. In the lack of other sources of knowledge, 

 there is left us the eulogy addressed by Kepler to David Fabri- 

 cius : " But also reading in your Prognosticon for the year 1618, 

 by which I am better informed concerning his [Jean's] too early 

 death," etc. ; and further on, " But, indeed, there is this excellent 

 little book concerning the solar spots in the year 1611," etc. The 

 author gives particulars concerning the first day of the discovery, 

 the method of observation by projection, and the conclusions 

 which Jean, aided by his father's advice, drew {spots fixed in the 

 body of the sun) concerning the sun's rotation around an axis. 

 Neither the Narration nor the writings of David, so far as they 

 are known to us, give any hints concerning the exact date of the 

 discovery, so that we were confined to guesses till M. Berthold 

 found the Prognosticon of David for 1615, which gave the 27th of 

 February (9th of March N. S.), 1611, as the exact date of the event. 

 Furthermore, a letter from David to Maestlin says that the Nar- 

 ration appeared at the time of the autumn fair of 1611, and this 

 is confirmed by Kepler. 



At this point in his learned essay Dr. Berthold discusses the 

 question of priority, for which a claim was earnestly pressed as 

 against Galileo by the Jesuit Scheiner, who assumed the name of 

 Apelles. It is really very singular, as it appears to the author, 

 that not a word was said of Jean Fabricius in this controversy, 

 and it might be inferred that both contestants. alike knew noth- 

 ing of the Narration, but for certain considerations and facts 

 adduced by Dr. Berthold which make this supposition exceed- 

 ingly improbable, if not impossible. 



It is proper to observe here that after the telescope was in- 

 vented all the discoveries in celestial objects became, as it were, 

 matters of course, and that, whatever noise might be made about 

 them at first, the merit of the observers is insignificant in com- 

 parison with that of the calculators who knew how to reason out 

 the basis of the true system. Even if it should be proved that 

 Galileo learned of the existence of the spots from Fabricius's 

 Narration, or from the letters of the false Apelles, the remarkable 

 fact remains that in his first reply to Welser he corrects the 



