150 TERHESTKIAL MAGNETISM. 



better magnetically explored northern regions, or to the 

 solution of questions which have been raised since 

 1840. Not to mix the uncertain with the certain, I will 

 therefore limit myself in the following description to the 

 Siberian portion of the Asiatic continent, so far as it is 

 known to us down to the parallel of 45 by the observa- 

 tions of Erman, Hansteen, Due, Kupffer, Fuss, and 

 myself. There is no other part of the earth's surface on 

 which magnetic lines could have been traced over so 

 great an extent of continental territory, a circumstance 

 which appears to me of some importance, as it did long 

 since to Leibnitz when speaking of the importance of 

 the Russian dominions in Europe and Asia in reference 

 to this subject. ( 195 ) 



Advancing from the west towards the east as the 

 usual direction followed by European expeditions to 

 Siberia, and commencing at the northern part of the 

 Caspian Sea, we find that, at what may be termed a 

 group of stations, viz. the little island of Birutschikassa at 

 Astrachan, the Elton Lake in the Kirghis steppe, and 

 Uralsk on the Jaik, places situated between the 

 latitudes of 45 43' and 51 12', and the East longitudes 

 of 46 37' and 51 24', the declination ranges from 

 10' E. to 37' W. ( 196 ) Further to the north this 

 line of declination inclines rather more to the north- 

 west, passing near Nishnei Novgorod, ( 197 ) (in 1828, 

 between Osablikowo and Doskino, in lat. 56, long. 43). 

 It is prolonged towards Russian Lapland, passing 

 between Archangel and Kola, or more exactly, accord- 

 ing to Hansteen in 1830, between Umba and Ponoi. ( 198 ) 

 In advancing eastward from this point, between the 

 parallels of 50 and 60, it is not until we have traversed 



