162 



ON THE PERIODICITY OF THE AURORA BOREALIS. 



Mar. 12. 



" 15. 



" 16. 



" 19. 



" 20. 



" 21. 



" 21. 



" 25. 



" 26. 



" 26. 



" 29. 



" 31. 

 Apr. 8. 

 8. 



" 9. 



" 10. 



" 10. 



" 10. 



" 12. 



" 13. 



" 14. 



" 15. 



" 15. 



" 16. 



" 17. 



" 17. 



" 18. 



" 19. 



« 20. 



" 22. 



" 22. 

 May 3. 

 5. 



" 8. 



" 9. 



" 10. 



" 10. 



" 14. 



" 17. 



" 18. 



" 18. 



" 18. 



« 19. • 



" 19. 



" 19. 



« 20. 



" 20. 



Yakoutsk. Kupffer. 



Christiania. Hansteen. Verden. Jahn. 



Burlington. Thompson. 



Burlington. Thompson. 



Burlington. Thompson. 



St. Ives, Hunts. Watts. 



Christiania. Hansteen. 



Warsaw. Jahn. 



Bonn. Schmidt. Leipsic. Jahn. 



Christiania. Hansteen. 



Sitka. Kupffer. 



Christiania. Hansteen. 



Burlington. Thompson. 



Christiania. Hansteen. 



Christiania. Hansteen. 



Cambridge. Bond. Lovering. 



Netv Haven. Herrick. Newton and Loomis. 



Litchfield. Hendriek. Christiania. Hansteen. 



Verden. Spengler. Jahn. 



Burlington. Thompson. 



Burlington. Thompson. 



New Haven. Bradley. Newton and Loomis. 



Christiania. Hansteen. 



Litchfield. Hendriek. 



Thompson. 

 Hansteen. 

 Hansteen. ' 

 Johnson. 



ifer/m^ow.Thompson. Bogoslowski.Kupffer. 1 

 New Haven. Herrick. Newton and Loomis.* 

 Caswell. Tennessee. Morris. 

 Thompson. 

 Thompson. 

 Thompson. 

 Thompson. Tennessee. Morris. 

 Providence, R. L Caswell. 

 New Haven. Herrick. Newton and Loomis 

 Thompson. 



Herrick. Newton and Loomis 



Bond. Lovering. 



Thompson. Providence. Caswell. 



Herrick. Newton and Loomis, 



Bond. Lovering. 



Herrick. Newton and Loomis. 



Burlington. 

 Christiania. 

 Christiania. 

 Neivberry. 



Providence. 

 Burlington. 

 Burlington. 

 Burlington. 

 Burlington. 



Burlington. 



New Haven. 



Cambridge. 



Burlington. 



New Haven. 



Cambridge. 



New Haven. 



Providence, R. I. Caswell. 



Cambridge. Bond. Lover nc;. 



New Haven. Herrick. Newton and L' omis. 



1 Annal. de l'Observ. Phys. Centrale de Russie, 1S52, p. 629. 

 3 Amer. Journ. Sci. Second Scries, XIV. 130-1. 



i Regents' Keporta of the Univ. New York, I8&3, p. 244. 



