OF THE PERIODICITY OF THE AURORA BOREALIS. 



41 



Jan. 26. Wittemherg. Weidler. Berlin. Kirch. 



" 26. Lincopice. Sparschuch. 



Feb. 4. St. Petersburg. Kraft. The Delisles. Mairan. 



" 13. St. Petersburg. The Delisles. Mairan. 



" 21. Italy. Beccari. Mairan. 



" 22. Italy. Beccari. Mairan. 



" 22. Wittemherg. Weidler. Thompson. 



" 24. St. Petersburg. The Delisles. Mairan. 



Mar. 4. St. Petersburg. Kraft. The Delisles. Mairan. 



" 13. Frobes and Mairan. 



" 15. Frobes and Mairan. 



" 20. Frobes and Mairan. 



" 22. Frobes and Mairan. 1 



" 23. Wittemherg. Weidler. Berlin. Kirch. Mairan. 



" 24. Wittemherg. Weidler. Berlin. Kirch. 



" 24. Frobes, Mairan, and Phil. Trans. 



" 25. Italy. Beccari. 



" 25. Wittemherg. Weidler. Mairan. 



" 26. St. Petersburg. The Delisles. Mairan. 



Apr. 16. St. Petersburg. The Delisles. Mairan. 



" 17. St. Petersburg. The Delisles. Mairan. 



" 18. St. Petersburg. The Delisles. Mairan. 



" 18. Wittemherg. Weidler. Lincopice. Sparschuch. 



" 19. St. Petersburg. The Delisles. Mairan. 



" 20. Boud. 



" 21. St. Petersburg. The Delisles. Mairan. 



" 22. Frobes and Mairan. 



" 23. Wittemherg. Weidler. Berlin. Kirch. Mairan. 



" 25. Boue" quotes from the Delisles. . 



Aug. 20. Plymouth. Huxham. 



" 22. St. Petersburg. The Delisles. Mairan. 



" 23. St. Petersburg. The Delisles. Mairan. 



" 27. St. Petersburg. The Delisles. Mairan. 



" 31. Plymouth. Huxham. Short. 



" 31. St. Petersburg. The Delisles. Mairan. 



Sept. 1. St. Petersburg. The Delisles. Mairan. 



" 10. St. Petersburg. The Delisles. Mairan. 



" 15. St. Petersburg. The Delisles. Mairan. 



" 16. St. Petersburg. The Delisles. Mairan. 



" 17. St. Petersburg. The Delisles. Mairan. 



" 18. St. Petersburg. The Delisles. Mairan. 



" 23. St. Petersburg. Kraft. The Delisles. Mairan. 



" 24. St. Petersburg. The Delisles. Mairan. 



" 24. Near London. Celsius. Phil. Trans. 



" 25. St. Petersburg. The Delisles. Mairan. 



Oct. 3. Plymouth. Huxham. 



" 11. St. Petersburg. Kraft. The Delisles. Mairan. 



1 Musschenbroek saw auroras from the 22d to 31st of March. 

 See Musschenbroek, Introd. § 2496 ; or Encyc. Method. I. p. 369. 



VOL. X. 6 



Jan. 7. 



" 22. 

 Feb. 6. 



" 7. 



" 13. 



" 16. 



" 17. 



" 17. 



" 17. 



" 18. 



« 20. 



" 20. 



" 27. 



" 28. 

 Mar. 1. 



" 15. 



" 30. 



" 30. 

 Apr. 3. 



Plymouth. Huxham. Mairan and Short. 



Bloomshurg. Celsius. 



Mairan, Short, and Phil. Trans. 



London. Celsius. Mairan and Phil. Trail-. 



St. Petersburg. The Delisles. Mairan. Short. 



St. Petersburg. The Delisles. Mairan. 



Lincopice. Sparschuch. 



Lincopice. Sparschuch. 



Wittemherg. Weidler. Mairan. 



St. Petersburg. Kraft. The Delisles. 



Lincopice. Sparschuch. 



Wittemherg. Weidler. Frobes and Mairan. 



Frobes and Mairan. 



St. Petersburg. The Delisles. Mairan. 



Frobes and Mairan. 



Frobes and Mairan. 



St. Petersburg. Kraft. The Delisles. Mairan. 



St. Petersburg. Kraft. The Delisles. Mairan. 



Peterborough. Neve. 1 



Edinhurg. Short, Mairan and Phil. Trans. 



1736. 2 



St. Petersburg. Kraft. The Delisles. Mairan. 



Celsius. Mairan and Phil. Trans. 



Plymouth. Huxham. 



Plymouth. Huxham. 



St. Petersburg. The Delisles. Mairan. 



St. Petersburg. Kraft. The Delisles. Mairan. 



Plymouth. Huxham. Lincopice. Sparschuch :; 



St. Petersburg. Kraft. The Delisles. 



Frobes, Mairan, and Phil. Trans. 



Plymouth. Huxham. 



Lincopice. Sparschuch. 



Cambridge, JSng. Celsius. 



Mairan and Phil. Trans. 



St. Petersburg. The Delisles. Mairan. 



Plymouth. Huxham. 



Italy. Beccari. Mairan. 



St Petersburg. The Delisles. Mairan. 



Lincopice. Sparschuch. 



Mairan. 4 



St. Petersburg. Kraft. The Delisles. 



> Phil. Trans. XL. 53. 



2 At Utrecht, 62 auroras were observed in this year. Date- 

 not given. See letter of Musschenbroek to Du Fay. Mem. dc 

 l'Acad. 1736, p. 504. 



8 Acta Lit. Sueciffl, IV. 249. 



4 See his general catalogue, p. 545 of Traite &e. Boue 

 ascribes the observation incorrectly to the Delisles. 



