1 50 COSMOS. 



and Tomsk, and are therefore not very different from the 

 meridian of the southern extremity of the peninsula of Hin- 

 dostan. The axis major of the closed oval group extends 

 28 of latitude as far as Corea. 



A similar configuration, although on a still larger scale, 

 is exhibited in the Pacific. The closed curves here form an 

 oval between 20 N. lat. and 42 S. lat. The axis major 

 lies in 130 W. long. That which most especially distin- 

 guishes this singular group (the greater portion of which 

 belongs to the southern hemisphere and exclusively to the 

 sea) from the continent of Eastern Asia is. as has been 

 already observed, the relative succession in the value of the 

 curves of variation. In the former, the eastern variation 

 diminishes, whilst in the latter the western variation in- 

 creases the farther we penetrate into the interior of the oval. 

 The variation in the interior of this closed group in the 

 southern hemisphere amounts, however, as far as we know, 

 only to from 8 to 5. Is it likely that there is a ring of 

 southern variation within the oval, or that we should again 

 meet with western variation farther to the interior of this 

 closed line of no variation ? 



Curves of no variation, like all magnetic lines, have their 

 own history, which, however, does not as yet unfortunately 

 date further back than two centuries. Scattered notices 

 may indeed be met with, as early even as in the 14th and 

 15th centuries, and here again Hansteen has the great merit 

 of having collected and carefully compared together all the 

 various data. It would appear, that the northern magnetic 

 pole is moving from west to east, and the southern magnetic 

 pole from east to west ; accurate observations show us, how- 

 ever, that the different parts of the isogonic curves are pro- 

 gressing very irregularly, and that where they were parallel 

 they are losing their parallelism ; and lastly that the domain 

 of the declination of one denomination, that is to say, east 

 or west declination, is enlarging and contracting in very 

 different directions in contiguous parts of the earth. The 

 lines of no variation in Western Asia and in the Atlantic 

 are advancing from east to west ; the former line having 

 crossed Tobolsk in 1716, while in 1761, in Chappe's time, it 

 crossed J ekatherinenburg and subsequently Kasan, and in 

 1829 it was found to have passed between Osablikowo and 



