682 POPULAR SCIENCE MONTHLY. 



thirteenth century the great Encyclopaedia of Matouan-lin con- 

 tains forty-five mentions of the phenomenon. The existence of 

 dark spots on the sun was recognized very anciently by the 

 aborigines of Peru. The Arabs have recorded prolonged observa- 

 tions of the disk of the sun, among which are those of 535 

 and 626. 



The oldest mention of a sun spot in Europe, a spot which was 

 supposed to be Mercury, is by an anonymous chronicler of the 

 eighth century. Different observations of sun spots before the 

 invention of the telescope are recorded in Zach's Monatliche Cor- 

 respondenz, vol. xv, 1807, and in Humboldt's Cosmos, vol. iii. 



The new instrument, invented in Holland, first permitted the 

 scientific study of the solar surface. Galileo appears to have seen 

 the spots on the sun for the first time in October, 1610, but did 

 not account for the nature of the phenomenon. Jean Fabricius 

 may have remarked the spots toward the end of the year 1610, 

 and certainly observed them in March, 1611. Scheiner reported 

 his discovery of the spots in April, 1611, but did not account for 

 what he saw. Harriott, who is believed by Zach to have seen the 

 spots as early as December, 1610, and whose manuscripts have 

 been examined by Rigaud, did not really see them till early in 

 December, 1611, and comes, consequently, only fourth in the order 

 of priority.* 



There have been lively controversies at different times concern- 

 ing the claims of these three astronomers to priority in the discov- 

 ery of the sun spots. The discussions were summarized by Arago 

 in an article published in VAnnuaire du Bureau des Longitudes in 

 1842. The question has been settled by deciding that Galileo first 

 saw the spots with the aid of the telescope, but that Fabricius 

 first announced their existence to the scientific world and pointed 

 out their nature. The texts were plain enough on this point, and 

 the discussion was prolonged more by the agitation of questions 

 concerning the meaning of words than by any need of clearing 

 up the facts. 



A work recently published by Dr. Gerhard Berthold on Fabri- 

 cius f contains a number of previously unpublished documents, 

 and throws light on some obscure points in the history of as- 

 tronomy at the beginning of the seventeenth century. 



An interesting analysis of this essay has been published by M. 

 E. Millosevich in the Atti of the Accademia dei Lincei of Rome. 

 While its main object is to establish the claim of Jean Fabricius 

 to priority in the discovery of the sun spots, it further furnishes 

 many facts previously unknown in the life of this astronomer and 



* These facts and dates are from Houzeau's Vade-mecum of Astronomy, 

 f Der Magister Johann Fabricius und die Sonnenflecken. 



