OF THE PERIODICITY OF THE AURORA B0REALI8. 



45 



Sept. 25. 



" 26. 



" 26. 



" 27. 



'< 28. 



« 28. 



" 29. 



" 30. 

 Oct. 1. 



" 3. 



" 24. 



" 25. 



" 29. 



" 30. 



" 31. 



Nov. 1. 



2. 



« 4. 



« 5. 



" 11. 



" 16. 



" 23. 



« 27. 

 Dec. 6. 



" 13. 



" 14. 



Jan. 2. 



" 3. 



" 4. 



" 23. 



" 25. 



" 27. 



" 27. 



" 30. 

 Feb. 1. 



" 23. 



" 24. 



" 27. 



« 28. 

 Mar. 1. 



Mairan, Short, and Phil. Trans. 

 Upsal. Celsius. 

 Mairan, Short, and Phil. Trans. 

 Upsal. Celsius. St. Petersburg. Kraft. 

 Upsal. Celsius. St. Petersburg. Kraft. 

 Wittemberg. "Weidler. Mairan. 

 Mairan, Short, and Phil. Trans. 

 Upsal. Celsius. Mairan and Phil. Trans. 

 Celsius. 



Upsal. 

 Upsal. 

 Upsal. 

 Upsal. 

 Upsal. 

 Upsal. 



Celsius. 



Celsius. 1 



Celsius. 



Celsius. 



Celsius. 



Mairan and Short. 



Mairan and Short. 

 Upsal. Celsius. Wittemberg. Weidler. Mairan, 

 Upsal. Celsius. 



Upsal. Celsius. Mairan and Phil. Trans. 

 Upsal. Celsius. 

 Upsal. Celsius. 

 Upsal. Celsius. 

 Italy. Beccari. Mairan. 

 Upsal. Celsius. 

 Upsal. Celsius. 



Mairan, Short, and Phil. Trans. 

 Mairan and Phil. Trans. 

 Upsal. Celsius. 



1740. 



St. Petersburg. Kraft. 



St. Petersburg. Kraft. 



Upsal. Celsius. 



St. Petersburg. Kraft. 



Upsal. Celsius. 3 



Pome. Didacus de Revillas. 3 BoutS. 



Mairan and Phil Trans. 



Upsal. Celsius. 



Celsius. 



Celsius. 



Celsius. 4 



Celsius. 



Celsius. 



Upsal. 



Upsal. 

 Upsal. 

 Upsal. 

 Upsal. 



St. Petersburg. Kraft. 



Si. Petersburg. Kraft. 



1 This and the nine following observations of Celsius are not 

 given in the Svenska Vetensk. Acad., but are contained in the 

 Me'm. Etrang. Paris, IV. 137. 



2 Svenska Vetensk. Acad. II. 67, and Acta Soc. Upsal. 1740, 

 p. 38, &c. 



8 This appears to have been the Aurora Austratis. Phil. Trans. 

 XLI. 744. 



* This and the observations of March 9 and 10, and of Aug. 

 29, are not given in the Acta Soc. Upsal. 



Mar. 4. Upsal. Celsius. 



" 9. Upsal. Celsius. 



" 10. Upsal. Celsius. 



" 11. Ujjsal. Celsius. 



" 19. Upsal. Celsius. 



" 23. Upsal. Celsius. Plymouth. Huxhaiu. 



" 23. St. Petersburg. Kraft. 



" 24. Upsal. Celsius. Plymouth. Huxham. 



" 24. St. Petersburg. Kraft. 



" 25. Plymouth. Huxham. St. Petersburg. Kraft. 



" 26. Upsal. Celsius. 



May 22. Upsal. Celsius. 



June 7. Plymouth. Huxham. 



July 10. Upsal. Celsius. 



Aug. 17. Upsal. Celsius. 



" 21. Upsal. Celsius. 



" 29. Upsal. Celsius. 



Sept.12. Upsal. Celsius. 



" 15. Upsal. Celsius. 



" 22. St. Petersburg. Kraft. 



" 25. Upsal. Celsius. St. Petersburg. Kraft. 



" 26. Upsal. Celsius. St. Petersburg. Kraft. 



Oct. 16. Upsal. Celsius. 



" 17. Mairan, Short, and Phil. Trans. 



" 20. Upsal. Celsius. 



" 23. Upsal. Celsius. 



" 24. Upsal. Celsius. St. Petersburg. Kraft. 



" 27. Upsal. Celsius. 



" 31. Upsal. Celsius. 



Nov. 3. Upsal. Celsius. Thompson. 



" 11. Upsal. Celsius. 



" 16. Upsal. Celsius. St. Petersburg. Kraft. 



" 18. St. Petersburg. Kraft. 



Dec. 7. Upsal. Celsius. 



" 18. Upsal. Celsius. 



" 20. Upsal. Celsius. 



1741. 



Jan. 12. Italy. Beccari. Mairan. 1 

 " 14. Upsal Celsius and Iliorter. 

 " 19. Upsal. Celsius and Hiorter. 

 " 20. Upsal. Celsius and Hiorter. 

 " 21. Upsal. Celsius and Hiorter. 

 " 21. St. Petersburg. Kraft. 

 " 21. Cambridge. Winthrop. 

 " 23. Upsal. Celsius and Hiorter. 



1 In Mairan's special catalogue it stands, Jan. 13. Traite' &c. 

 p. 507. 



2 Svenska Vetensk. Acad. III. 14, and Acta Soc. Upsal. 1750, 

 p. 100. 



