18 ON THE RECENT SECULAR TERIOD 



continued with diminishing intensity all night, and streamers were seen until an 

 hour after daj'break. 



In this account, the fact is first distinctly enunciated that when the aurora is 

 unusually brilliant, there sometimes occur two fits of greatest intensity at an interval 

 of about four hours. The following are given as the successive positions of the 

 corona : 



At 2 h. 31 m. centre of corona 75° 25' alt.— S. 4° 27' E. az. 

 " 39 . . . . 74° 55' 3.30 



" 42 . . . . 74° 40' 5.07 



Dip, at New Haven, 73° 27'; Declination, G° 10' W. 



The magnetic needle was much disturbed. Between 10 h. 44 m. and 11 o'clock, 

 it traversed an arc of 3° 41'. After midnight the range did not exceed 1°. 



Of the great aurora of November 14th of the same year, Professor Barnard, of 

 the University of Mississippi, then resident in the city of New York, prepared a full 

 account from the statements of different observers, which was inserted in the Ameri- 

 can Journal of Science (XXXIV, 267). 



At New Haven the exhibition was first noticed about 6 o'clock, while a very thin 

 cloud covered the sky from which a light snow was falling. All things appeared 

 as if dyed in blood. The entire atmosphere, the surface of the earth, the trees, the 

 tops of houses, and in short the whole face of nature, were tinged with the same 

 rosy hue. The disturbance of the magnetic needle was cpuite remarkable, its entire 

 range, according to Mr. Herrick, being nearly six degrees. At 6 h. 26 m. it stood at 

 3° 10' W.; and 9 h. 10 m. at 9° 7' W. From a tabular statement, containing 70 

 observations made between 5 h. 40 m. and 11 h. it appeared that the influence of 

 the aurora was not uniform in producing a deflection of the needle in the same 

 direction. At 6 h. 6 m. having returned to its normal place from east to west, 

 it suddenly turned and moved rapidly eastward for five minutes, and thus oscil- 

 lated continually. 



Professor Barnard observed this aurora in the city of New York, where the cloud 

 was thinner than at New Haven, and only a few light flakes of snow were falling, 

 so that the exhibition was recognized as early as a quarter before 6. After several 

 variations of intensity, the phenomenon rallied a few minutes before 9, when Pro- 

 fessor Barnard was summoned to witness a new exhibition of auroral magnificence, 

 "the glories of which no tongue could tell." It formed a grand corona, and had 

 the other characteristics of an aurora of the first class. The duration of the maxi- 

 mum state of intensity was very remarkable. For three-quarters of an hour after 

 its formation, which took place about 9 o'clock, the corona continued, with variable 

 brightness, to maintain its position at the magnetic pole. Within a few minutes 

 after 9, the southern sky was as completely filled with auroral columns as the 

 northern. For a long time, therefore, the spectator was overspread by a perfect 

 canopy of glory. Professor Barnard continued his observations the greater part of 

 the night, to see whether, as had been observed before, there would be a recurrence 

 of the display at a later hour. Such proved to be the fact, as the aurora returned, 



