146 COSMOS. 



3 east of Cook's Sandwich Land, and to about 9 30' east 

 of South Georgia ; it then approaches the Brazilian coast, 

 which it enters at Cape Frio 2 east of Rio Janeiro and tra- 

 verses the southern part of the New Continent no farther 

 than 36' S. lat., where it again leaves it somewhat to the 

 east of Gran Para, near Cape Tigloca on the Rio do Para, 

 one of the secondary outlets of the Amazon, crossing the 

 geographical equator in 47 44' W. long., then skirting along 

 the coast of Guiana at a distance of eighty-eight geogra- 

 phical miles as far as 5 N. lat., and afterwards following the 

 arc of the small Antilles as far as the parallel of 18, and 

 finally touching the shore of North Carolina near Cape 

 Lookout, south-east of Cape Hattaras in 34 50' N. lat., 

 74 8' W. long. In the interior of North America, the 

 curve follows a north-western direction as far as 41 30' N. 

 lat., 77 38' W. long., towards Pittsburgh, Meadville, and 

 Lake Erie. We may conjecture that it has advanced very 

 nearly half a degree farther west since 1840. 



The Australo-Asiatic curve of no variation (if according 

 to Erman we consider the part which rises suddenly from 

 Kasan to Archangel and Russian Lapland as identical with 

 the part in the sea of Molucca and Japan) can scarcely be 

 followed as far as 62 in the southern hemisphere. This 

 starting point lies farther west from Van Diemen's Land than 

 had hitherto been conjectured, and the three points, at which 

 Sir James Ross crossed the curve of no variation on his Ant- 

 arctic voyage of discovery in 1840 and 1841, 90 are all situated 

 in the parallels of 62, 54. 30, and 46, between 133 and 

 135 40' E. long. ; and therefore mostly in a meridian-like 

 direction running from south to north. In its further course, 

 the curve crosses Western Australia from the southern coast 

 of Nuyts' Land about 10 3 W. of Adelaide to the northern 

 coast near Vansittart river and Mount Cockburn, from 

 whence it enters the sea of the Indian Archipelago in a region 

 of the world, in which the inclination, declination, total in- 

 tensity, and the maximum and minimum of the horizontal 

 force were investigated by Captain Elliot from 1846 to 1848, 

 with more care than has been done in any other portion of 

 the globe. Here the line passes south of Flores and through 



* Sir James Ross, Op. dt. vol. i, pp. 104, 310, 317. 



