24 



ON TIIE PERIODICITY OF THE AURORA BOREALIS. 



1690. Oct. Short and Mairan. 



" Nov. Short and Mairan. 



Dec. Short and Mairan. 



1692. April 12. F robes, Mairan. and Acad. Coll. 



" May 22. Lehmann, Frobes, 1 Mairan, Acad. 



'• Sept. 14. Breslau. Grebner.' Frobes. 



1603. Nov. 10. Lehmann and Frobes. 



" 10. Mairan and Acad. Coll. 



Nov. 22. Breslau. Grebner, Frobes, Mairan, 



1694. Mar. 31. Breslau. Grebner, Frobes, Mairan, 



" April 4. Breslau. Grebner, Frobes, Mairan, 



1665. Oct. 5. Breslau. Grebner, Frobes. Mairan, 



12. Breslau. Grebner. Frobes, Mairan, 



" " 31. Breslau. Grebner, Frobes, Mairan, 



" Nov. 20. Breslau. Grebner, Frobes. Mairan, 



1696. May 12. Breslau. Grebner. Frobes. Mairan. 



Sept. 26. Breslau. Grebner, Frobes, Mairan. 



" Nov. 6. Breslau. Grebner, Frobes. Mairan. 



" " 18. Breslau. Grebner. Frobes, Mairan. 



Aug. 18. Meissen and Bohtein. Lehmann. 



- 18. Frobes, Mairan. and Acad. Coll. 



1698. Feb. 24. Breslau. Grebner, Frobes, Mairan. 

 '• •• 26. Breslau. Grebner, Frobes, Mairan. 



May IS. Frobes, Mairan, and Acad. Coll. 



" Sept. 30. Bossa. 3 ? Lehmann, Mairan. Frobes, 



Nov. 15. Breslau. Grebner, Frobes, Mairan. 



" •• 27. Breslau. Grebner. Frobes. Mairan, 



" Dec. 7. Breslau. Grebner, Frobes, Mairan, 



« " 23. Breslau. Grebner, Frobes, Mairan, 



" " 28. Breslau. Grebner, Frobes, Mairan, 



" Jan. 3. Breslau. Grebner, Frobes, Mairan, 



" Feb. 17. Breslau. Grebner, Frobes. Mairan. 



1699. Feb. 23. Breslau. Grebner, Frobes, Mairan. 



25. Breslau. Grebner, Frobes, Mairan. 



" April 17. Breslau. Grebner, Frobes, Mairan, 



" '• 20. Breslau. Grebner, Frobes, Mairan, 



" •• 21. Breslau. Grebner, Frobes, Mairan. 



" •■ 28. Breslau. Grebner, Frobes. Mairan. 



" June 18. Breslau. Grebner, Frobes, Mairan, 



1 Mairan places this by mistake on March 22. Traite &c, p. 471. 



2 In Diario Meteorol. Wratislav. p. 7, &c In regard to the 

 numerous observations of supposed auroras recorded by Grebner, 

 between 1692 and 1700, Frobes remarks: "Dubinin est, fateor, 

 noctemne insigoiter serenam (qute siderea vocari passim hie solet) 

 an luminis borealis spectacuhan aliquod noctis sublustris vocabulo 

 auctor signilieaverit. Sed nolui tamen interim quamquam dubias 

 observationes hasce prorsus oniirtere : ne scilicet enrarius hoc 

 quicqnid rei est, exploraudi ansam mihi atque aliis denegasse 

 videar," p. 62. Acad. Coll. is omitted for want of room on Greb- 

 ner's dates, and on Sept. 30. 



3 Near Freiburg. 



1704. 



Grebner, Frobes. Mairan, 

 Grebner, Frobes. Mairan. 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frolics. Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes. Mairan, 

 ( .n liner, Frobes. Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes, Mairan, 

 Grebner. Frobes, Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes. Mairan, 

 Grebner, Frobes. Mairan, 1 

 Spain. Rieo. 2 

 and. Jechonius. 3 

 d Mairan. 

 Piltrram. 



'Between 1700 and 1751, the Collection Academique appears to 

 be merely a transcript from Mairan 's catalogue of auroras, with 

 occasionally an accidental error, mostly omissions. The auroras of 

 Nov. t. 1709, and March x. 1711, are given be Nov. 11 and March 

 11. The auroras of April 11, 1716, April 10 and 11, 1717, of Oct. 

 11, 171S, of Feb. 11, 1719, of Feb. 11 and April 11, 1720, of Feb. 

 11, 1721, of Jan. 17, 1724, are all omitted. The auroras of May 1 

 and 3, 1728, are given as the aurora of May 13. An aurora on 

 Mav 26, 1737, is interpolated, and the auroras of Nov. 26 and 30 

 of that year are omitted. The auroras which belong to March 

 and April, 1741, are repeated for 1742, and the actual auroras of 

 March. 1742, are omitted. Since the date of Mairan's catalogue, 

 j auroras are given for Feb. 4, 1759, at Berlin and Fregbourg, and 

 for Feb. S, 1759, at Paris. 



- Mem. de I' Acad. Cienc, Madrid. III. 77. 



3 In dem Fnvorgreiflichen Bedencken tiber das Zn Abau in 

 Finland — am Himmel wahrgenomene Wnnder-und Feuer-Zei- 

 chen. 



