8 ON THE RECENT SECULAR PERIOD 



same paper, a beautiful aurora had been seen in every part of Denmark as early 

 as the 8th of September. 



From the preceding accounts it appears that after a long period of comparative 

 repose, the aurora borealis suddenly presented itself to the existing generation both 

 in the north of Europe and in the United States, under forms far more imposing 

 than most persons on the stage had ever witnessed before ; and if we pursue its 

 history, we shall find that these exhibitions increased, during the following years, in 

 number and intensity. This increase is strikingly shown by Dallon's Catalogue of 

 Auroras, extending from the year 1794 to 1834 inclusive, embracing those observed 

 during this period in Great Britain and Ireland. If we compare the seven years 

 previous to 1827, with the seven years following, the numbers are as follows : — 



1820 



1821 



1822 



1823 



1824 t 



1825 



182G 



Total 7 



In intensity, the increase during the latter period is equally remarkable, as will 

 be evident by descending to particulars. 



In 1828, September 29th, there was a grand auroral arch seen in Great Britain 

 and Ireland, and also in the State of New York. 1 Although in 1829, the number 

 recorded by Dalton was 18, yet none occurred above the third class. The follow- 

 ing year, 1830, still manifested an increasing series, the number given in the same 

 catalogue being 32, those of April 19th, August 20th, September 7th, September 

 17th, Oct. 5th, December 11th and 12th, having been more or less splendid, and 

 some of them entitled to rank in the second class. For 1831, only 23 auroras 

 are given, but that of January 7th is characterized as "one of the finest auroras 

 ever seen," and as lasting from sunset till morning. It was observed in England, 

 Scotland, Paris, and Brussels. 2 That of March 7th is said to have been fine; but 

 most of the exhibitions of 1831 were of the ordinary kind. In the American Journal 

 of Science for October, 1831, is a paper by General Martin Field, giving an account 

 of auroras observed by him at Fayetteville, Vermont (lat. 42° 58'). lie says: 

 "On examining my meteorological journal, which I have kept for many years, I 

 find the occurrence of the aurora borealis has varied from 10 to 28 nights in dif- 

 ferent years, and that for ten years previous to the last, the average number of 

 evenings when it has been seen is 18 annually. But within the last twelve 

 months, from May, 1830, to May, 1831, the aurora has been visible on 56 nights, 

 which is twice the number of any former year of which I have any record." The 



1 Dalton's Ess., 221; Brewster's Jour., I, 256, X, 146 ; Phil. Mag., V, 153. 



s Luke Howard, Meteor. Ess., Ill, 873; Phil. Mag., IX, 127, 151, 233; Jameson's Jour , X, 381. 



