ON THE PERIODICITY OF TI1E AURORA BOREALIS. 



161 



Hammerfest. Noodt. 

 Hammerfest. Noodt. 

 C/tristiania. Hansteen. 



Jahn. 



New York: Hough. 

 C/irisliaiiia. Ilansteen. 



Jahn. 



Hammerfest. Noodt. Jahn. 

 New Tori: Hough. 



Christiania. Hansteen. Hammerfest. Noodt. 



New York. Hough. 



Christiania. Hansteen. 



New York. Hough. 



Hannover. Pape. Jahn. 



New York. Hough. 



Batty Bay. Bellot. 1 



Christiania. Ilansteen. Yakoulsk. Kupffer. 



Belgium. Montigny.* 



Cambridge. Bond. Lovering. 



Litchfield. Hendrick. 



Cambridge. Bond. Lovering. 



Osnabriick. Jahn. 



1852. 



Jahn. 



Christiania. Ilansteen. 



Hammerfest. Noodt. 



Cambridge. Bond. Lovering. 



Litchfield. Hendrick. Providence. Caswell. 



Burlington. Thompson. 8 Sonora. Goddard 



New Haven. Herrick. Newton and Loomis 



San Francisco. Gibbon. Tennessee. Morris. 4 



Hammerfest. Noodt. Sitka. Kupffer. 



Worcester. Chandler. 



Bonn. Schmidt. Jahn. Yakoulsk. Kupffer, 



Elberfeld. Jahn. Aix-la-ChapeUe. Heis. 



Burlington. Thompson. 



Yakoulsk. Kupffer. 



Burlington. Thompson. 



Worcester. Chandler. Litchfield. Hendrick. 



Burlington. Thompson. Providence. Caswell. 



Aix-la-ChapeUe. Heis. Jahn. 



Hammerfest. Noodt. Jahn. 



Burlington. Thompson. 



Christiania. Hansteen. 



« Memoirs of J. R. Bcllot, &c. II. 73. 



* Amer. Jo urn. Sci. Second Series, XIV. 289. 



* Amer. Journ. Sci. Second Series, XV. 459. 



* Amer. Journ. Sci. Second Series, XVII. 140. and XXIX. 260, 



VOL. X. 21 



New Haven. Olmsted. Litchfield. Hendrick.' 



Christiania. Ilansteen. Yakoulsk. Kupffer. 



Netc Haven. Herrick and Olmsted. 



Litchfield. Hendrick. Burlington. Thompson. 



Christiania, Hansteen. Hammerfest. Noodt. 



New Haven. Herrick. Newton and Loomis. 



Providence. Caswell. Christiania. Ilansteen. 



Cambridge. Bond. Lovering. 



New Haven. Herrick and Olmsted. 



Burlington. Thompson. Newberry. Johnson. 



< 'atharinebovrg and Sitka. Kupffer. 



Yakoulsk and lchim. Kupffer. 3 



Christiania. Ilansteen. Kertchinsk. Kupffer. 



Cambridge. Bond. Lovering. 



New Haven. Herrick and Olmsted. 



Burlington. Thompson. Newberry. Johnson. 



Litchfield. Hendrick. Rochester. Dewey. 



Tennessee. Morris. Sa?i Francisco.' Gibbon. 



Bunse. Stevenson. St. Ives, Hunts. Watts. 4 



Bonn. Schmidt. Jahn. 



Barnaoul and Kertchinsk. Kupffer. 6 



Christiania. Ilansteen. Ichim. Kupffer. 



Cambridge. Bond. Lovering. 



New Haven. Herrick. Newton and Loomis. 



Litchfield. Hendrick. Newberry. Johnson. 



Yakoulsk and Tobolsk. Kupffer. 



Christiania. Hansteen. 



Verden. Pape. Leipsie, <§'<"• Jahn. 



Christiania. Ilansteen. Tobolsk: Kupffer. 



Hammerfest. Noodt. 



Bunse. Stevenson. St. Ives. Hunts. Watts. 



Cambridge. Bond. Lovering. 



Burlington. Thompson. 



Sitka. Kupffer. 



Cambridge. Bond. Lovering. 



Christiania. Ilansteen. 



New Haven. Herrick. Newton and Loomis. 



Litchfield. Hendrick. Burlington. Thompson. 



Christiania. Ilansteen. Sitka. Kupffer. 



New Haven. Herrick. Newton and Loomis. 



Christiania. Hansteen. 



Burlington. Thompson. Jahn. 



1 Amer. Journ. Sci. Second Series, XIII. 426. 



• Annal. dc l'Observ. Phys. Centralc do Russic, 1859, Suppl. 

 p. 95. 



* Dr. Gibbon says, that he saw the aurora at San Francisco, 

 once in January, and once in February, 1852. Smithsonian Re- 

 ports, 1854, p. 258. Amer. Jour. Sci. Second Series, XXVII. 260. 



4 Proc. Brit. Assoc. XXI. 32. 



6 Annal.de l'Observ. Phys. Centralc dc Russie, 1852, pp. 127, 

 213,311, et 561. 



