OF THE COSMOS. COLOUR OF THE FIXED STARS. L13 



conversant with Arabian and Persian astronomy, may 

 succeed in discovering in the intervals from El-Batani 

 (Albategnius) and El-Fergani (Alfraganus) to Abdurrahman 

 Sufi, arid Ebn-Junis (from 880 to 1007), and from Ebn- 

 J unis to Nassir-Eddin andlllugh Beig (from 1007 to 1437) 

 some evidence respecting the colour of Sirius at that time. 

 El-Fergani (properly called Mohammed Ebn-Kethir El- 

 Fergani), who, as early as the middle of the 10th century, 

 observed at Rakka ( Aracte) on the Euphrates, names as " red 

 stars" (" stellse ruffse" in the old Latin version of 1590) 

 Aldebaran, and, perplexingly enough, ( 216 ) the now yellow, 

 or at the utmost reddish-yellow, Capella, but not Sirius. 

 On the other hand, if we suppose that Sirius had then ceased 

 to be a red star, it would seem strange that El-Fergani, who 

 follows Ptolemy throughout, should not have pointed out the 

 change of colour in a star of such note. Negative reasons 

 are, however, seldom conclusive ; and it should be remarked 

 that, in the same passage, El-Fergani does not mention the 

 colour of Betelgeuze (a Orionis), which is now, as in Ptolemy's 

 time, a red star. 



It has long been recognised, that among all the brightly- 

 shining fixed stars in the heavens, Sirius occupies the first 

 and most important place in chronological respects, and in 

 its historical connection with the earliest development of 

 human civilization in the Yalley of the Nile. According to 

 the most recent researches of Lepsius, ( 21 ?) the Sothic period, 

 and the heliacal rising of Sothis (Sirius), on which subject 

 Biot has furnished an excellent memoir, remove the complete 

 construction of the Egyptian calendar to the highly ancient 

 epoch of almost 33 centuries before our Era, when not only 

 the summer solstice, and consequently the commencement 



VOL III. I 



