Observations of the Aurora Borealis, 1850-51. 61 



In December 1850, every night but five, 5, 10, 18, 19, 20, but 

 all the displays of a feeble character. In January 1851, every 

 night but two, 5, 12 ; many of the displays very feeble, several 

 of them seen only by Mr. Anderson at Athabasca, and on the 

 whole a much smaller proportion than usual, extending to low 

 latitudes. In February we have it every night*, some of the 

 displays of great beauty, although I imagine they will have been 

 far exceeded by those of February 1852. The display of Fe- 

 bruaiy 18th, 1851, was one of those remarkable instances of the 

 simultaneous absence of cloud, and intense development of au- 

 rora over a veiy large part of the northern hemisphere, which, 

 from their frequent occuiTence, appear to have more than an ac- 

 cidental connexion. It was seen at eveiy station, with excep- 

 tion only of the Pelly Banks, from the polar circle to the United 

 States, where no less than thirty-eight stations have forwarded 

 accounts of it to the Smithsonian Institution ; it extended also 

 to Europe, having been recorded at Sandwick Manse, Orkney. 

 The display of February 28th was almost as universal. It is 

 remarkable that in both cases the phsenomenon was first seen, 

 in absolute time, at the most eastern stations, notwithstanding 

 the earher commencement of darkness at the extreme north, 

 where the difierence of latitude in some cases more than com- 

 pensates the difierence of longitude ; it would appear from this 

 that the aurora does not commonly appear at a station upon any 

 meridian until that meridian generally is in darkness ; a result, 

 which, if established by the whole body of evidence, vAW be both 

 new and interesting. For example, in the following list I have 

 entered the hour of sunset in mean time of Gottingen at each 

 station, and the hour at which the aurora is fu'st recorded in the 

 same ; it is not to be supposed that each observer seized the 

 exact time of fu-st visibility, but in two of the examples at least 

 the general result is sufficiently clear, namely, that it was seen 

 at the lower and eastern stations sooner than at the northern 

 but more westerly stations, although there is no reason to be 

 given why it should not have appeared at the latter as soon as 

 at the foi-mer, dayhght having ended there. 



* Every night but two, February 2 and 1 6. 



