44 COSMOS. 



The constant navigation of the Indian Ocean, washing the 

 shores of Eastern Africa, was the earliest means especially 

 since the time of the Lagides arid the Monsun-navigation of 

 making mariners acquainted with the stars near the Southern 

 Pole. As early as the middle of the tenth century, we find, 

 as already observed, that the Arabs had given a name to the 

 larger of the Magellanic Clouds. This designation is, accord- 

 ing to Ideler's researches, identical with that of the White 

 Ox, el-bakar, of the celebrated astronomer Derwisch Abdur- 

 rahman Sufi of Rai, a city in the Persian province of Irak. 

 In his Introduction to the Knowledge of the Starry Heav- 

 ens, which he composed at the court of the sultans of the dy- 

 nasty of the Buy ides, he says that "below the feet of the Suhel 

 (by which he expressly means the Suhel of Ptolemy, Canopus, 

 although the Arabian astronomers named many other large 

 stars of Argo, el-sejina, Suhel) there is a ' white spot,' which 

 is invisible both in Irak (in the district of Bagdad and in 

 Nedsch, ' Nedjed') and in the more northern and mountain- 

 ous part of Arabia, but may be seen in the Southern Tehama, 

 between Mecca and the extremity of Yemen, along the coast 

 of the Red Sea."* The relative position of the White Ox to 

 Canopus is here indicated with sufficient accuracy for the 

 naked eye ; for the Right Ascension of Canopus is 6h. 20m., 

 and the eastern margin of the larger Magellanic Clouds lies 

 in Right Ascension 6h. The visibility of the Nubecula ma- 

 jor in northern latitudes can not have been appreciably af- 

 fected by the precession of the equinoxes since the tenth cen- 

 tury, for the maximum distance from the north had already 

 been attained long before that period. If we follow the re- 

 cent determination of position for the larger cloud by Sir John 

 Herschel, we shall find that it was perfectly visible as far 

 north as 17 in the time of Abdurrahman Sufi ; at the pres- 

 ent time it is seen in about 18 north latitude. The south- 

 ern clouds must therefore have been visible throughout the 

 whole of southwestern Arabia, in Hadhramaut (noted for its 

 frankincense) as well as in Yemen, the ancient seat of civil- 

 ization of Saba, and the long-established colony of the Joctan- 

 ides. The southernmost extremity of Arabia, at Aden, on 



* Ideler, UntersucTinngcn uber den Ursprung i/nd die Bcdeutung der 

 Slemnamen, 1809, p. xlix., 262. The name Abdurrahman Sufi was 

 contracted by Uiajjli Beg from Abdurrahman Elm-Omar Elm- Moham- 

 med Elm-Salil Abu'l-Hassan el-Snfi el-Razi. Ulugh Beg, who, like 

 Nassir-eddin, amended the Ptolemaic star-positions from his own ob- 

 servations (1437), admits that he borrowed from Abdurrahman Sufi's 

 work the positions of 27 southern stars, not visible at Samarcand. 



