NOTES. 



kix 



in Charezm. His sojourn in India, and the writing of his history of India 

 (Tankhi-Hind), the most remarkable fragments of which have been made 

 known by Reinaud, belong to the years 1030 1032. 



( 352 ) p. 224. Sedillot, Materiaux pour servir a 1'Histoire comparee de 

 Sciences mathematiques chez les Grecs ct les Orientaux, T. i. p. 50 89 ; the 

 same, in the Comptes rendus de 1'Acad. des Sciences, T. ii. 1836, p. 202, T. 

 xvii. 1843, p. 163173, T. xx. 1845, p. 1308. M. Biot maintains, in 

 opposition to this opinion, that the fine discovery of Tycho Brahe by no 

 means belongs to Abul-Wefa ; that the latter was acquainted, not with the 

 " variation," but only with the second part of the " evection" (Journal des 

 Savans, 1843, p. 513532, 609626,719737; 1845, p. 146166; 

 and Comptes reiidus, T. xx. 1845, p. 13191323). 



C 353 ) p. 224. Laplace, Expos, du Systeme du Monde, Note 5, p. 407. 



C 35 *) p. 225. On the observatory of Meragha, see Delambre, Histoire de 

 1'Astronomie du Moyen Age, p. 198 203 ; and Am. Sedillot, Mem. sur les In- 

 strumens arabes, 1841, p. 201 205, where the gnomon is described with a 

 circular opening. On the peculiarities of the star catalogue of Ulugh Beig, 

 see J. J. Sedillot, Traiie des Instruments astronomiques des Arabes, 1834, 

 p. 4. 



P 5 ) p. 225. Colebrooke, Algebra, with Arithmetic and Mensuration from 

 the Sanscrit of Brahmegupta and Bhascara, Lond. 1817. Chasles, Aper9u 

 historique sur 1'Origine et le Developpement des Methodes en Geometric, 

 1S37, p. 416 502; Nesselmann, Versuch einer kritischen Geschichte der 

 Algebra, Th. i. S. 3061, 273276, 302306. 



I 356 ) p. 225. Algebra of Mohammed Ben-Musa, edited and translated by 

 F. Rosen, 1831, p. 8, 72, and 196199. The mathematical knowledge of 

 India was extended to China about the year 720 ; but this was at a period 

 when many Arabians were already settled in Canton and other Chinese cities. 

 Reinaud, Relation des Voyages fuits par les Arabes dans 1'Inde et a la Chine, 

 T. i. p. 109 ; T. ii. p. 36. 



C 357 ) p. 226. Chasles, Histoire de 1'AJgebre, in the Comptes rendus, 

 T. xiii. 1841, p. 497524, 601626; compare also Libri, in the same, 

 p. 559563. 



p 8 ) p. 226. Chasles, Aper$u historique des Methodes en Geome'trie, 

 1837, p. 464472. The same, in the Comptes rendus de 1'Acad. des 

 Sciences, T. viii. 1839, p. 78; T. ix. 1839, p. 449; T. xvi. 1843, p. 156 

 173, and 218246; T. xvii. 1843, p. 143154. 



C 359 ) p. 227.- Humboldt, iiber die bei verschiedenen Volkern ublichen 



