ON TIIE PERIODICITY OF THE AURORA BOREALIS. 



51 



Aug. 20. 



" 30. 



" 31. 



Sept. 3. 



5. 



" 10. 



" 27. 



" 27. 

 Oct. 2. 



« 9. 

 Nov. 3. 

 Dec. 2. 



" 3. 



" 4. 



" 5. 



" 8. 



" 13. 



«' 17. 



" 18. 



" 24. 



" 26. 



Cambridge. 1 Winthrop. Lovering. 

 Cambridge. Winthrop. Lovering. 

 Italy. Beccari. Mairan. 

 Tubingen. Kraft. 

 Cambridge. Winthrop. Lovering. 

 Wiltemberg. Weidler. Mairan. 

 Cambridge. Winthrop. Lovering. 

 Italy. Beccari. Mairan. 

 Gottingen. Hollmann. 2 

 Hollmann. 

 Kraft. 

 Huxham. 

 Weidler. Mairan. 

 Bischoff. 3 

 Bischoff. 

 Bischoff. 

 Bischoff. 



Plymouth. Huxham. 



Jan. 



« 9. 



" 11. 



" 13. 



" 31. 

 Feb. 2. 



" 3. 



« 5. 



" 8. 



" 16. 



« 18. 



« 19. 



" 22. 



" 27. 

 Mar. 6. 



" 9. 



" 12. 



" 18. 



« 19. 



Gottingen. 



Tubingen. 



Plymouth. 



Witlemberg. 



Steinebrunn. 



Steinebrunn. 



Steinebrunn. 



Steinebrunn. 



Upsal. Celsius. 



Vpsal. Celsius. 



Italy. Beccari. Mairan. 



Cambridge. Winthrop. Lovering. 



1748. 

 Steinebrunn. Bischoff. 

 Steinebrunn. Bischoff. 

 Steinebrunn. Bischoff. 

 Upsal. Celsius. 

 Steinebrunn. Bischoff. 

 Steinebrunn. Bischoff. 

 Steinebrunn. Bischoff. 

 Upsal. Ferner. 4 

 Plymouth. Huxham. 

 Cambridge. Winthrop. Lovering. 

 Steinebrunn. Bischoff. 

 Steinebrunn. Bischoff. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 



Witlemberg. Weidler. Mairan. 

 Stuttgart. Volzius. 5 

 Upsal. Ferner. 

 Steinebrunn. Bischoff. 

 Upsal. Ferner. 

 Upsal. Ferner. 



1 Celsius says auroras were seen at Upsal often in August, 

 and several times in Sept. Oct. and November. 



2 Comm. Gott. III. 43, &c. Also IV. 18, &c. 

 8 N. Comm. Petrop. III. 391. 



« Svenska Vetensk. Acad. XIII. 101. 

 6 N. Comm. Petrop. III. 391. 



Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Ipsal. Ferner. 

 Upsal. Ferner. 



Cambridge. Winthrop. Lovering. 

 Stuttgart. Volzius. 

 Stuttgart. Volzius. 

 Tubingen. Kraft. 

 Steinebrunn. Bischoff. 

 Stuttgart. Volzius. 

 Gottingen. Hollmann. 

 Tubingen. Kraft. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Ipsal. Ferner. 

 Upsal. Ferner. 

 Gottingen. Hollmann. 

 Cambridge. Winthrop. Lovering. 

 Gottingen. Hollmann. 

 Plymouth. Huxham. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Upsal. Ferner. 

 Steinebrunn. Bischoff. 

 Upsal. Ferner. 1 

 Italy. Beccari. Mairan. 

 Steinebrunn. Bischoff. 

 Cambridge. Winthrop. Lovering. 

 Steinebrunn. Bischoff. 2 

 Cambridge. Winthrop. Lovering. 

 Upsal. Ferner. Plymouth. Huxham. 

 Upsal. Ferner. 

 Ipsal. Ferner. 

 Upsal. Ferner. 



Cambridge. Winthrop. Lovering. 

 Near Philadelphia. Kalm. 

 Upsal. Ferner. 

 Upsal. Ferner. 



Witlemberg. Weidler. Mairan. 

 Stuttgart. Volzius. 



1749. 



Jan. 4. Stuttgart. Volzius. 



1 Auroras were seen at Upsal on two other days in October. 



2 Auroras were seen at Upsal six times in November. 



