ON THE PERIODICITY OF THE AURORA BOREALIS. 



o — 

 Ol 



Oct. 7. 



" 8. 

 ■ 8. 

 " 8. 

 " 8. 

 " 10. 

 " 16. 

 " 23. 

 " 23. 

 " 23. 

 " 25. 

 " 28. 

 " 29. 

 Nov. 2. 

 « 4. 

 " 6. 

 " 11. 

 " 17. 

 " 18. 

 " 27. 

 " 29. 

 " 30. 

 . 1. 

 4. 

 5. 

 6. 

 7. 



18. 



20. 



21. 



27. 



30. 



30. 



31. 



Dec 



Jan. 



1. 



3. 



4. 



5. 



6. 

 16. 

 17. 

 18. 

 26. 



Sweden. Celsius. Frobes and Mairan. 



Pilgram and Phil. Trans. 



Plymouth. Huxham. Wittemlerg. "Weidler. 



St. Petersburg. Kraft. The Delisles. 



Italy. Beccari. Berlin. Kirch. 



Sweden. Celsius. Frobes. 



Mairan, Pilgram, and Phil. Trans. 



Wittemberg. Weidler. Mairan and Phil. Trans. 



Sweden. Celsius. Frobes and Mairan. 



Wittemberg. Weidler. Berlin. Kirch. 



Sweden. Celsius. Frobes and Mairan. 



Pilgram and Phil. Trans. 



Mairan 1 and Pilgram. 



Paris. Mairan. Pilgram. 



Frobes and Mairan. 



St. Petersburg. Kraft. The Delisles. Mairan. 



Sweden. Celsius. Frobes and Mairan. 



Phil. Trans and Mairan. 



Celsius, Frobes, and Mairan. 



Sweden. Celsius. Frobes and Mairan. 



Siceden. Celsius. Frobes and Mairan. 



Sweden. Celsius. Frobes and Mairan. 



Sweden. Celsius. Frobes and Mairan. 



Phil. Trans, and Mairan. 



Sweden. Celsius. Frobes and Mairan. 



Sweden. Celsius. Frobes and Mairan. 



. Mairan. Pilgram. 



Sweden. Celsius. Frobes and Mairan. 

 Sweden. Celsius. Frobes and Mairan. 



. Mairan. Pilgram. 



St. Petersburg. Kraft. The Delisles. Mairan. 

 St. Petersburg. Kraft. The Delisles. Mairan. 

 Sweden. Celsius. Frobes and Mairan. 

 Plymouth. Huxham. Short. 

 Sweden. Celsius. Frobes and Mairan. 

 Sweden. Celsius. 



1732. 

 Sweden. Celsius. Frobes and Mairan. 

 Sweden. Celsius. Frobes and Mairan. 

 St. Petersburg. Kraft. The Delisles. Mairan. 

 Sweden. Celsius. 2 



Celsius. 



Celsius. Mairan. 3 



Celsius. Frobes and Mairan. 



Celsius. Frobes and Mairan. 



Sweden. 

 Sweden. 

 Sweden. 

 Siceden. 

 Wittemberg. Weidler. Mairan. 



1 Mem. del' Acad. 1731, p. 385. 



2 Acta Lit. Suecia:, III. B. 44. 



8 Compare pp. 492 and 544, of Traite' par Mairan. 



Sweden. Celsius. Frobes and Mairan. 

 Sweden. Celsius. Frobes and Mairan. 

 Swede?!. Celsius. Frobes. 

 Paris. Mairan. 1 

 Plymouth. Huxham. Short. 

 St. Petersburg. Kraft. The Delisles. 

 Sweden. Celsius. Frobes and Mairan. 

 St. Petersburg. Kraft. The Delisles. 

 Siceden. Celsius. Frobes and Mairan. 

 Sweden. Celsius. Frobes and Mairan. 

 Wittemberg. Weidler. Mairan. 

 Sweden. Celsius. Frobes and Mairan. 

 St. Petersburg. Kraft. The Delisles. 

 Sweden. Celsius. Frobes and Mairan. 

 Plymouth. Huxham. Short. 

 Sweden. Celsius. Frobes and Mairan. 

 St. Petersburg. Kraft. The Delisles. Mairan. 

 Frobes and Mairan. 

 Frobes and Mairan. 



St. Petersburg. The Delisles. Mairan. 

 Berlin. Kirch. Mairan. 

 Sweden. Celsius. Frobes. 

 Italy. Beccari. Mairan. 

 Sweden. Celsius. Frobes and Mairan. 

 St. Petersburg. The Delisles. Mairan. 

 St. Petersburg. The Delisles. 

 Berlin. Kirch. Phil. Trans. 

 Wittemberg. Weidler. Mairan. 

 Frobes and Mairan. 



Sweden. Celsius. Frobes and Mairan. 

 St. Petersburg. The Delisles. Mairan. 

 St. Petersburg. The Delisles. Mairan. 

 St. Petersburg. The Delisles. Mairan. 

 Frobes and Mairan. 



Sweden. Celsius. Frobes and Mairan. 

 Frobes and Mairan. 

 St. Petersburg. Kraft. The Delisles. 

 Berlin. Kirch. Phil. Trans. 

 Sweden. Celsius. Frobes and Mairan. 

 St. Petersburg. Kraft. The Delisles. 

 Sweden. Celsius. Frobes and Mairan. 

 Siceden. Celsius. Frobes. 

 Paris. Mairan. 

 Si?. Petersburg. The Delisles. 

 Italy. Beccari. Mairan. 

 Sweden. Celsius. Frobes. 

 St. Petersburg. The Delisles. 

 Sweden. Celsius. Frobes and Mairan. 



1 Me'm. de i'Acad. 1733, p. 47S. 



