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On the Frequency of Thunder-Storms in the Polar Begions. 

 By M. Von Baer. 



M. Arago, in his elaborate work on thunder, published in the 

 year 1838, has stated it as an established fact, " that^ in the wide 

 ocean^ and in islands, it never thunders beyond the 75° of N, lati- 

 tude ; and that at the 70^ the phenomenon is very seldom heard — 

 Bcarcely once a-year^ M. de Baer, who was travelling in the 

 extreme north of Europe in 1837, having had occasion to make 

 observations which exhibited the limit of storms, if such limit 

 there is, much nearer to the pole, has communicated to the 

 Imperial Academy of Petersburg in a note, and under form of 

 a letter, dated the 7th of May, to M. Jacobi, the remarks he 

 himself has made on this subject, and those he has collected 

 from other authors. Of these we shall supply a summary in 

 as few words as possible. 



M. de Baer commences by directing attention to the cir- 

 cumstance, that M. Arago has based his general conclusion 

 upon an insufficient number of documents. " In truth," he 

 remarks, " M. Arago has only consulted the English voyages 

 undertaken in our own times to the northern parts of Ameri- 

 ca and Spitzbergen, and the observations made in Iceland by 

 M. Thorstensen for a period of two years only. At the same 

 time, many of these voyagers were for a long time on the wide 

 ocean, or in islands of no great extent, and no one knows bet- 

 ter than M. Arago that the farther you are removed from con- 

 tinents, the more rarely do you encounter thunder-storms. 

 But, in addition to this, more extended observations prove, 

 that in the very same spots where these. passing voyagers have 

 not heard thunder, it has from time to time been heard by 

 others, so that this proposition may be stated, ' That no north- 

 ern latitude has been attained by man in which thunder is not 

 known to occur? It even thunders at Spitzbergen, though cer- 

 tainly very rarely. In Nova Zembla, I have witnessed a thun- 

 der storm beyond the 73°, and the narratives of the hunters of 

 the walrus contain many accounts of it."" 



We shall commence, however, with Iceland. M. Arago'^s 

 notice of this island is as follows : — *' Iceland is often adduced 



