50 



ON THE PERIODICITY OF THE AURORA BOREALIS. 



1 Mem. de l'Acad., 1747, p. 473. 



2 Force quotes from " Voyage to Hudson's Bay," II. 11, to the 

 effect that auroras were seen, in Lat. 58° and Long. 49°, in 

 June, &c, 1746. 



Nov. 5. Steinebrunn. Bischoff. 1 



" 8. Tubingen. Kraft. 



" 14. Upsal. Celsius. 



" 15. Upsal. Celsius. 



" 16. Upsal. Celsius. 



" 17. Wittemberg. Weidler. Mairan. 



" 21. Tubingen. Kraft. 



Dec. 1. Tubingen. Kraft. 



" 14. Cambridge. Winthrop. Lovering 



" 14. Upsal. Celsius. 



" 15. Upsal. Celsius. 



" 18. Upsal. Celsius. Tubingen. Kraft. 



" 27. Upsal. Celsius. 



" 29. Tubingen. Kraft. 



1747. 



Upsal. Celsius. 



Upsal. Celsius. Tubingen. Kraft. 



Wittemberg. Weidler. Mairan. 



Plymouth. Huxham. 



Cambridge. Winthrop. Lovering. 



Upsal. Celsius. 



Upsal. Celsius. 



Upsal. Celsius. 2 Plymouth. Huxham. 



Upsal. Celsius. 



Tubingen. Kraft. 8 



Cambridge. Winthrop. Lovering. 



Cambridge. Winthrop. Lovering. 



Upsal. Celsius. 



Tubingen.. Kraft. 



Upsal. Celsius. 



Upsal. Celsius. 



Upsal. Celsius. 



Upsal. Celsius. 



Upsal. Celsius. 



Mairan and Phil. Trans. 



Upsal. Celsius. 



Upsal. Celsius. 



Upsal. Celsius. 



I psal. Celsius. Plymouth. Huxham. 



I r psal. Celsius. 



Tubingen. Kraft. 



Upsal. Celsius. 



Tubingen. Kraft. 



Cambridge. Winthrop. Lovering. 



Cambridge. Winthop. Lovering. 



1 N. Comm. Petrop. I. 149. 



2 Svenska Vetensk. Acad. XI. 276. 



3 N. Comm. Petrop. III. 390. 



