18 



ON THE PERIODICITY OF THE AURORA BOREALIS. 



778. 



Lyeosthenes and Frobes. 

 Mairan, Pilgram, and Acad. Coll. 

 Quetelet, 1 and Boguslawski. 

 Frytschius and Frobes. 

 Lyeosthenes, Frobes, and Chasles. 

 Ado, Frobes, and Pilgram. 

 Bouquet, Pilgram, and Quetelet. 

 Lyeosthenes, Frobes, Mairau, 2 and 

 Academical Collection. 

 Academical Collection. 

 Bouquet, Pilgram, and Quetelet. 

 Pilgram. 



Pertz 3 and Quetelet. 

 Bouquet, Quetelet, and Boguslawski. 

 Pertz, Quetelet, and Boguslawski. 

 Bouquet, Pertz, and Pilgram. 

 Quetelet and Boguslawski. 

 Bouquet, Pertz, Quetelet, Bogusl. 

 Pertz, Bouquet, Quetelet, Bogusl. 

 Pertz, Bouquet, Quetelet, Bogusl. 

 Rome. Tylkowsky. Frobes. 

 Pertz, Bouquet, Quetelet, Bogusl. 

 Pertz, Bouquet, Quetelet, Bogusl. 

 Pilgram. 



Leibnitz, 4 Frobes, Mairan, Pilgram. 

 Leibnitz, Frobes, Mairan, Pilgram. 

 Leibnitz, Frobes, Mairan, 5 Pilgram. 

 Bouquet, Pertz, Quetelet, Bogusl. 

 Pilgram. 



Quetelet, Pilgram, Boguslawski. 

 Lyeosthenes, Frytschius, Frobes. 

 Mairan, Chasles, Boguslawski. 

 Bouquet, Quetelet, and Boguslawski. 

 Feb. 7. Bouquet, Duchesne, 8 Quetelet, Bogusl. 

 Pertz, Quetelet, and Boguslawski. 

 Quetelet 9 and Boguslawski. 

 ■ance. Lyeosthenes, Mairan, Frobes. 



1 He quotes Bouquet. Recueil des Historiens des Gaules., 

 HI. 139 et V. 72. 



: Mairan thinks it uncertain whether this appearance was in 

 808 or 809. Traite", p. 190. 



3 Quetelet quotes his Monumenta Germanise Historicce, II. 226. 



4 Miscellanea Berolinensia ad Incrementum Scient. I. 137. 



5 Mairan quotes the Annals of St. Bertin for the Luminous 

 Phenomena of this year. Boguslawski ranks them as star- 

 showers. 



6 Pendant plusieurs nuits le ciel est rouge comme du sang : &c. 



7 This is the date to which Mairan reduces IV. Idus Aug. 



8 Historian Francomm Scriptores. III. 474. 



8 He quotes Reiffenberg. Me'm. de l'Acad. Brux. VII. 63. 



930. 

 937. 



Feb. 19. 

 Feb. 14. 



940.? Dec. 

 956. Sept. 

 970. 

 978. 

 979. 



992. 



St 



993. 



Acad. Coll. Chasles, Boguslawski. 



Bouquet, Duchesne, Pertz, Quetelet. 



Bouquet, Quetelet and Boguslawski. 

 7. Frobes, 1 Mairan and Acad. Coll. 

 Lyeosthenes, Pilgram, and Boguslawski. 2 

 Oct. 28. Frytschius, Frobes, Mairan, 8 and P. 

 Nov. 2. Lyeosthenes, "Wolffius, and Frobes. 

 Zahn, Mairan, 4 Acad. Coll. and Quetelet. 

 Oct. 21. Pilgram. 

 Dec. Calvisius and Mairan. 



Jan. 6. Short 5 and Mairan. 



Leibnitz, Frobes, Mairan, Pilgram. 



Lyeosthenes, Frobes, Mairan, Acad. 



Frytschius, Frobes, Mairan, Acad. 



Boue, 7 and Acad. Coll. 



Lyeosthenes, Frobes, Mairan. 



Pilgram, Acad. Coll. and Chasles. 8 



Frytschius and Frobes. 



Pilgram. 



Godin, 9 Mairan, and Pilgram. 



"Wolffius, Frobes, 10 and Mairan. 



Pilgram and Acad. Coll. 



Ingram 11 and Pilgram.? 



Lyeosthenes, Frobes, Mairan, Acad. 



Lyeosthenes, Frobes. Mairan. Acad. 



Frytschius, Lyeosthenes, Frobes. 



Short, Mairan, and Acad. Coll. 

 19. u Italy. Lyeosthenes, Frobes, Mairan. 



Pilgram, Acad. Coll. and Quetelet. 



Frytschius and Frobes. (Doubtful.) 



Lyeosthenes, Frobes, Mairan, Acad. 

 Lyeosthenes, Frobes, Pilgram, and Chasles. 

 Feb. 22. 14 Liege. Lyeosthenes and Frobes. 



1 Baluzius. Chronic. Floriar. p. 305. 



2 This is the appearance which Frobes assigns to the year 971. 



3 Mairan (p. 191.), quotes Le Chronique Hirsaugiense de 

 1 'Abbe Tritheme. The date here given is probably in old style. 



4 Mairan quotes the Chronique de Liechtenaw. ( Urspergen- 

 sis.) The original date is V. Kal. Nov. 



6 A General Chronological History of the Air, Weather, etc. 

 II. 178. 



6 Probably Old Style. 



7 Sitzungsberichte der Kaiserl. Akad. Wien. XXII. 13. 



8 Boguslawski is probably correct in not regarding this as an 

 aurora. 



9 Mem. de l'Acad. Paris, 1723, p. 296. The date is probably 

 in old style. 



10 In Chronico Urspergens. (Liechtenaw,) pp. 240 et 245. 



11 The Saxon Chronicle, pp. 317-8. 



12 This was a star-shower and not an aurora. 



13 We may doubt with Boguslawski whether this was an aurora. 



14 In Chronico Urspergens. (Liechtenaw,) p. 274. 



