NOTES. 17 



p) p. 175. Tdeler, Handbuch der Chronologic, Bd. i. S. 212 and 829. 

 P J ) p. 176. Delambre, Histoire de I'Astronomie aucienne, T. i. p. 290. 

 p) p. 176. Bokh has examined in his Philolaos, S. 118, whether the 

 Pythagoreans were early acquainted, through Egyptian sources, with the pre- 

 cession, under the name of the motion of the heaven of the fixed stars. Letronne 

 (Observations sur les Representations zodiacales qui nous restent de 1'Anti- 

 quite, 1824, p. 62) and Ideler (Handbuch der Chronol. Bd, i, S. 192) vindi- 

 cate Hipparchus's exclusive claim to this discovery. 

 P) p. 177. Ideler on Eudoxus, S. 23. 

 P) p. 177. The planet discovered by Le Verrier. 

 C 277 ) p. 178. Compare Kosmos, Bd. ii. S. 141, 146, 149 and 170 (Engl. 

 trans. Vol. ii. p. 106, 111, 114, and 136). 



P) p. 179. Wilhelm von Humboldt iiber die Kawi-Sprache, Bd. i. S. 

 xxxvii. 



P) p. 180. The superficial extent of the Roman Empire under Augustus 

 (according to the boundaries assumed by Heeren, in his Geschichte der Staaten 

 des Alterthums, S. 403 470) has been calculated by Professor Berghaus, the 

 author of the excellent Physical Atlas, at rather more than 100000 (German) 

 geographical square miles. This is about a quarter greater than the extent of 

 1600000 square miles assigned by Gibbon, in his History of the Decline and 

 Fall of the Roman Empire, Vol. i. Chap. i. p. 39, but which he indeed says 

 must be taken as a very uncertain estimate. 

 C 280 ) p. 181. Veget. de Re Mil. iii. 6. 



C 281 ) p. 181. Act. ii. v. 371, in the celebrated prophecy which, from the 

 time of Columbus' son, was interpreted to relate to the discovery of America. 

 O 82 ) p. 182. Cuvier, Hist, des Sciences naturelles, T. i. p. 312 328. 

 P) p. 182. Liber Ptholemei de Opticis sive Aspectibus; the rare manu- 

 script of the Royal Library at Paris (No. 7310), was examined by me on the 

 occasion of discovering a remarkable passage on the refraction of rays in 

 Sextus Empiricus (adversus Astrologos, lib. v. p. 351, Fabr.) The extracts 

 which I made from the Parisian manuscript in 1811 (therefore before 

 Delambre and Venturi) are given in the introduction to my Recueil d'Obser- 

 vations astronomiquec, T. i. p. Ixv. lx\. The Greek original has not come 

 down to UB ; we have only a Latin translation of two Arabic manuscripts of 

 Ptolemy's Optics. The Latin translator gives his name as Amiracus Euge- 

 nius, Siculus. Compare Venturi, Comment, sopra la Storia e le Teorie 

 dell' Ottica, Bologna, 1814, p. 227 ; Delambre, Hist, de I'Astronomie an- 

 cienne, 1817, T. i. p. 51, and T. ii. p. 410432. 



