294 COSMOS. 



and in the Almagest of Ptolemy, are stellar clusters which ap- 

 pear to the naked eye with a nebulous lustre. 4 This designa- 

 tion, latin izednebulosce, passed in the middle of the thirteenth 

 century into the Alphonsine Tables, probably through the pre- 

 ponderating influence of the Jewish astronomer, Isaac Aben 

 Sid Hassan, Chief Rabbi of the wealthy synagogue at Toledo. 

 The Alphonsine Tables first appeared in print in 1483 at 

 Venice. 



The first notice of a remarkable aggregation of innumerable 

 true nebulous spots, blended with stellar swarms, dating from 

 the middle of thetenth century, is in the writings of an Ara- 

 bian astronomer, Abdurahman Sufi, a native of the Persian 

 Irak. The White Ox, which he saw shining with a milky 

 light far below Canopus, was undoubtedly the larger Magel- 

 lanic cloud, which with an apparent breadth of nearly .twelve 

 lunar diameters, extends over a portion of the heavens mea- 

 suring forty-two square degrees. No mention is made by 

 European travellers of this phenomenon until the beginning 

 of the sixteenth century, although, 200 years earlier, the 

 Normans had advanced as far along the Western coasts of 

 Africa as Sierra Leone (8 30' N. Lat.). 5 It might have 

 been expected that a nebulous mass of such vast extent, 



4 Cosmos, vol. iii. pp. 121 and note, and 190 and note. 



5 Prior to the expedition of Alvaro Becerra. The Por- 

 tuguese advanced beyond the equator in 1471. See Hum- 

 boldt's Examen critique de VHist. de la Geographic du 

 Nouveau Continent, torn. i. pp. 290-292. In eastern Africa 

 the Lagides had availed themselves, for purposes of commerce, 

 of the passage along the Indian Ocean, and, favoured by the 

 south-west monsoon (Hippalus), had passed from Ocelis in the 

 Straits of Bab-el-Mandeb to the Malabar emporium of Muziris 

 and to Ceylon (Cosmos, vol. ii. p. 539, and note). Although 

 the Magellanic Clouds must have been seen in all these 

 voyages, we meet with no record of their appearance. 



