14fc COSMOS. 



Asia through the Gulf of Ochotsk. It is much to be lamented, 

 that notwithstanding the frequent voyages made to and from 

 India, Australia, the Philippines, and the north-east coasts 

 of Asia, a vast accumulation of materials should remain 

 buried and unheeded in various ships' logs, which might 

 otherwise lead to general views, by which we might be en- 

 abled to connect Southern Asia with the more thoroughly 

 explored parts of Northern Asia and thus to solve questions 

 which were started as early as 1840. In order, there- 

 fore, not to blend together known facts with uncertain hypo- 

 theses, I will limit myself to the consideration of the Siberian 

 portion of the Asiatic continent, as far as it has been ex- 

 plored in a southerly direction to the parallel of 45 by Erman, 

 Hansteen, Due, Kupfler, Fuss, and myself. In no other part 

 of the earth has so extended a range of magnetic lines been 

 accessible to us in continental regions ; and the importance 

 which European and Asiatic Russia presents in this respect 

 was ingeniously conjectured even before the time of Leib- 

 nitz. 95 



95 I drew attention as early as 1843 to the fact, which I had ascer- 

 tained from documents presenved in the Archives of Moscow and, 

 Hanover (Asie Centrale, t. iii, pp. 469 476), that Leibnitz, who con- 

 structed the first plan of a French expedition to Egypt, was also the first 

 who endeavoured to profit by the relations which the Czar, Peter tho 

 Great, had established with Germany in 1712, by using his influence to 

 secure the prosecution of observations for " determining the position of 

 the lines of variation and inclination, and for insuring that these observa- 

 tions should be repeated at certain definite epochs" in different parts of 

 the Russian empire, whose superficies exceed those of the portions of 

 the moon visible to us. In a letter addressed to the Czar, discovered 

 by Pertz, Leibnitz describes a small hand-globe, or terrella, which is 

 still preserved at Hanover, and on which he had represented the curve 

 at which the variation is null (his linea magnetica primaria). Leibnitz 

 maintains that there is only one line of no variation, which divides the 

 terrestrial sphere into two almost equal parts, and hag four pwncta, 

 flexus contrarii, or sinuosities, where the curves are changed from con- 

 vex to concave. From the Cape dft Verd it passes in lat. 36 towards 

 the eastern shores of North America, after which it directs its course 

 through the South Pacific to Eastern Asia and New Holland. This line 

 is a closed one, and passing near both poles, it approaches closer to the 

 southern than the northern pole ; at the latter, the declination must 

 be 25 west, and at the former only 5. The motion of this important 

 curve must have been directed towards the north pole at the beginning 

 of the 18th century. The variation must have ranged between and 

 15 east over a great portion of the Atlantic Ocean, the whole of the 



