ON THE PERIODICITY OF THE AURORA BOREALIS. 



337 



AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. 



1 The observations at Arkhangel were made by Silvestroff. See Mem. de VAcad. St. Petersburg, S. G, T. IV. et V. 

 pp. 237 etc. See observations in Iceland and Nis'hne Kolymsk in 1820 - 3. 



VOL. X. 



4a 



