ON THE PERIODICITY OF THE AURORA BOREALIS. 



27 



Phil. Trans., Mairan, and Short. 1 

 Mairan, Pilgram, and Phil. Trans. 

 Frobes, Mairan, Maraldi, and Pilgram. 

 Frobes, Mai ran. Maraldi, and Pilgram. 

 Lynn. Folkes. Celsius, Frobes, and Mairan. 

 Maraldi, Pilgram, and Phil. Trans. 

 Berlin. Kirch. Celsius and Mairan. 

 Frobes and Mairan. 

 Frobes and Mairan. 

 Frobes, Mairan, Maraldi, and Pilgram. 



Short. Mairan. 



Short. 2 Mairan. 



Paris. Mairan and Pilgram. 

 Paris and London. 



Frobes, Mairan, and Pilgram. 

 Lynn. Folkes. Paris and London. 

 Mairan, Pilgram, and Phil. Trans. 

 Celsius and Mairan. 3 



Short. Mairan. 



Berlin. Kirch. Frobes and Mairan. 



Mairan. 

 Mairan. 



Pilgram. 



Kirch. 

 Short. 



Kirch. 



Felt. 4 



Maraldi. 5 



Berlin. 



Salem. 



Paris. 



Celsius, Frobes, Mairan, and Pilgram. 



Frobes and Mairan. 



Phil. Trans. Mairan. 



Salem. Felt. Phil. Trans. 



Celsius, Frobes, and Mairan. 



Frobes and Mairan. 



Frobes and Mairan. 



Maraldi and Pilgram. 



1721. 



Lynn. Folkes. Mairan. 

 Pilgram and Phil. Trans. 

 Mairan, Pilgram, and Phil. Trans. 

 Berlin. Kirch. Lynn. Folkes. 

 Mairan and Phil. Trans. 



Short. Mairan. 



Berlin. Kirch. Dublin? 



— Liebknecht. 7 



Celsius, Frobes, Mairan, and Pilgram. 



1 See Mairan, p. 525. 



2 Boue' refers to Auroras on March 11 and April 11. 



3 Boue' quotes Celsius for October 22. 

 « Hist, of Salem, II. 137. 



6 Memoires de l'Acad., 1721, p. 2. 



6 Phil. Trans., XXXI. 180. 



» ActaErud., 1721, p. 157. 



Feb. 22. — 



" 23. Frobes and Mairan. 



" 28. Frobes and Mairan. 



Mar. 1. Berlin. Kirch. Celsius. 



" 1. Liebknecht, 1 Mairan, and Pilgram. 



" 12. Frolics and Mairan. 



" 29. Frobes and Mairan. 



Sept. 12. . Celsius and Mairan. 



" 1C. Liebknecht 2 and Pilgram. 



" 22. Celsius, Mairan, anil Phil. Trans. 



" 28. Lynn. Folkes. Short. 



Oct. 3. Frobes and Mairan. 



" 21. Celsius, Mairan, and Pilgram. 



" 23. Frobes and Mairan. 



" 24. Frobes and Mairan. 



" 31. Frobes and Mairan. 



Nov. 1. Frobes and Mairan. 



" 2. Mairan and Phil. Trans. 



" 29. Paris. Maraldi, Boue-. 



1722. 



Jan. 7. Mairan and Pilgram. 



" 8. Mairan and Pilgram. 



" 9. Mairan and Pilgram. 



" 12. Mairan and Pilgram. 



" 17. Mairan and Short. 



" 22. Frobes and Mairan. 



" 23. Frobes, Mairan, and Short. 



" 25. Frobes and Mairan. 



Feb. 12. Celsius and Mairan. 



" 13. Celsius and Mairan. 



" 16. Celsius and Mairan. 



" 20-. Mairan and Pilgram. 



" 23i Frobes and Mairan. 



" 24. Frobes and Mairan. 



" 27. Frobes and Mairan. 



Mar. 1 ? Celsius and Mairan. 3 



" 17. Frobes and Mairan. 



" 18. Frobes and Mairan. 



" 25 ? Mairan. 



" 27. Frobes and Mairan. 



April 5. Frobes and Mairan. 



May 23. Frobes and Mairan. 



June 4. Frobes and Mairan. 



i ActaErud., 1721, p. 157. 



2 Pharus, p. 66. 



3 Mairan gives the aurora of March 1 in Celsius's catalogue, 

 but not in his own general catalogue, p. 494 ; he gives the aurora 

 of March 25 in his general catalogue, but in none of the special 

 catalogues. 



