ON THE PERIODICITY OF THE AURORA BOREALIS. 



123 



1 Phil. Trans. 1839, p. 277. 



2 Observ. Magnet. Comra. Nord. 



8 Annuaire Magnet, et Meteor, de Eussie, 1839, p. 283. 



Christiania. Hansteen. Edinburgh. Necker. 

 Bossekop and Jupvig. Lottin. 

 Bossekop and Jupvig. Lottin. 

 New York. Hough. England. Hough. 

 Bossekop and Jupvig. Lottin. 

 Boston. Hale. Lovering. 

 New Haven. Herrick. Newton and Loomis. 

 New York. Hough. Providence. Caswell. 

 Washington, D. C. Gilliss. 

 Brussels. Quetelet. Ashurst. Snow. 

 Christiania. Hansteen. Edinburgh. Necker. 1 

 Bossekop and Jupvig. Lottin. 

 Christiania. Hansteen. 

 Bossekop and Jupvig. Lottin. 

 New Haven. Herrick. Newton and Loomis. 

 New York. Hough. 

 Bossekop and Jupvig. Lottin. 

 Bossekop. Lottin. 

 Bossekop. Lottin. 

 Bossekop. Lottin. 

 Bossekop. Lottin. 

 Bossekop. Lottin. 

 Bossekop. Lottin. 

 Bossekop. Lottin. 

 New Haven. Herrick 

 New York. 

 Christiania. 

 Bossekop. 

 Bossekop. 

 Neio York. 

 Bossekop. 

 Bossekop. 

 Bossekop. 

 Bossekop. 

 Bossekop. 

 Bossekop. 



Neiv Haven. Herrick. Newton and Loomis. 

 Christiania. Hansteen. Edinburgh. Necker. 

 Bossekop. Lottin. 

 New York. Hough. 



Christiania. Hansteen. Bossekop. Lottin. 

 Bossekop. Lottin. 

 Eutin, Holstein. Roth. Schmidt. 2 

 Christiania. Hansteen. Bossekop. Lottin. 

 Bamaoul. Kupffer. 8 Bossekop. Lottin. 

 Bossekop. Lottin. 



i Ann. Chem. et Phys. Third Series, I. 270. 



2 Grunert. Arch. Math, und Phys. XXVI. 74. 



8 Annuaire Magnet, et Meteor, de Russie, 1839, p. 170. 



Newton and Loomis. 



Hough. Bossekop. Lottin. 

 Hansteen. Bossekop. Lottin. 

 Lottin. 

 Lottin. 



Hough. 

 Lottin. 

 Lottin. 

 Lottin. 

 Lottin. 

 Lottin. 

 Lottin. 



Bossekop. 



Edinburgh. 



Lottin. 



Necker. 



Edinburgh. Necker. 



