NOTES. xliii 



expressed supported by a great nautical authority to whom I always refer with 

 great pleasure, Sir James Ross (Voyage in the Southern and Antarctic Regions, 

 vol. i. p. 105). 



( 187 ) p. 146. Acosta, Historia de las Indias, 1590, lib. i. cap. 17. I have 

 touched in a previous volume on the question whether, through the medium of 

 the controversy between Boud and Beckborrow, the opinion of Dutch navigators 

 respecting four lines of no declination may not have influenced Halley's hypo- 

 thesis of four magnetic poles. (Kosmos, Bd. ii. S. 483; English edition, Note 

 434.) 



( 188 ) p. 147. In a general point of view, especial attention is due to the 

 isogonic line of 22\ W. in the interior of Africa: this line connects very diffe- 

 rent systems of isogonic lines and, according to Gauss's theoretically constructed 

 map, runs from the eastern part of the Indian Ocean across Africa and the 

 Atlantic to Newfoundland. Perhaps the honourable extension which the British 

 Government have given, in the present year, to the African Expedition of 

 Richardson, Barth, and Overweg, may lead to the solution of this magnetic 

 problem. [The particular year in which this note was written is not named. 

 The reference is probably to the employment of Dr. Vogel, which was specially 

 for magnetic determinations. Ed.] 



( 189 ) p. 147. Sir James Ross crossed the line of no declination in 61| S. 

 lat. and 22 28' W. long. (Voyage to the Southern Seas, vol. ii. p. 357.) In 

 70 43' S. lat. and 16 46' W. long., in March 1843, Captain Crozier found the 

 declination 1 38', and was therefore very near the line of no declination. 

 Compare Sabine, On the Magnetic Declination in the Atlantic Ocean for 1840, 

 in the Phil. Trans, for 1849, Pt. II. p. 233. 



( 19 ) p. 148. Sir James Ross, Voyage to the Southern Seas, vol. i. p. 104, 

 310 and 317. 



( 191 ) p. 148. Elliot, in the Phil. Trans, for 1851, Pt. I. p. 331, PI. XIII. 

 " Sandal-wood Island " is a small island on which sandal-wood (in Malay and Ja- 

 vanese, "tschendana;" Sanscrit, " tschandana;" Arabic, "fsandel") is obtained. 



( 192 ) p. 149. According to Barlow, and according to the map entitled " Lines 

 of Magnetic Declination computed according to the Theory of M. Gauss," in 

 the Report of the Committee for the Antarctic Expedition, 1840. According to 

 Barlow, the line of no declination coming from Australia enters the Asiatic con- 

 tinent at the Gulf of Cambay and then turns again immediately north-eastward, 

 by Thibet, China, and Formosa, to the Sea of Japan. According to Gauss, the 

 Australian line ascends simply through Persia, by Nishnei Novgorod, to Lap- 

 land. This great geometer regards the line of no declination of the seas of Japan 

 and the Philippines, as well as the closed oval group of isogonic lines in Eastern 



