1G ON THE RECENT SECULAR TERIOD 



leaves which made so conspicuous a figure in the great exhibitions of November, 

 1835, and April, 183G. Although the moon was shining in the east, and was but 

 little past the full, yet the distinctness of the auroral lights seemed scarcely impaired 

 by it. This is remarkable; perhaps there is not more than one other instance on 

 record where so splendid an exhibition of the aurora borealis was witnessed in the 

 presence of so full a moon. 



The magnetic needle was watched attentively by Mr. E. C. Herrick, and was 

 observed to undergo extraordinary fluctuations at one time (7 h. 41m.), deviating 

 a Avhole degree west of its normal position, and at another time traversing 45 

 minutes in two minutes of time. The barometer had previously been subject to 

 uncommon variations. On the night of the 21st, between 11 and 12 o'clock, it 

 stood at 28.70 inches, a depression seldom equalled at this place. From that time 

 it had steadily risen, and during the aurora it stood at 30.1 inches. Its entire range 

 from December 19th, when it was 30.91, was very remarkable, since its maximum 

 in ordinary years is seldom above 30.70, and its minimum seldom below 29 inches, 

 making the entire annual range 1.7 inches; whereas, during the 24 hours preceding 

 this aurora, the range was 1.4 inches. The thermometer early in the evening of 

 the aurora was at 20° (Fahr.), but sank rapidly, and at 10 o'clock was only 4° above 

 zero, and before morning fell quite to zero. The zodiacal light was at that time 

 very conspicuous in the S. W. in the evening, and continued through the two or 

 three months, considerably brighter than in ordinary years. 



This great aurora called out many good observers in various parts of the United 

 States and in Canada, and the periodicals of the day abound with descriptions of it. 

 At Annapolis (Maryland), lat. 39°, it was accurately observed by President Hum- 

 phreys, of St. John's College. Instead of the twilight blush in the north, an appear- 

 ance which it first presented at New Haven, as early as six o'clock, Dr. Humphreys, 

 although abroad and engaged in taking an astronomical observation, discovered 

 nothing of it until 40 minutes after six, when his attention was suddenly arrested by 

 a column of red light which shot up from the southwest. At its maximum, the 

 aurora afforded light sufficient to cast a deep shadow from trees, houses, and other 

 objects, while the snow reflected a rich crimson. The magnetic needle constantly 

 vibrated in the horizontal arc, and was so affected in the dip, as to be brought 

 closely into contact with the glass plate; and, on inclining the needle so as to cause 

 it to traverse, the difference of declination between 9 o'clock that evening and sun- 

 rise next morning was more than ten degrees} This result is remarkable, not only 

 for the extent of the change of declination, which, I believe, is altogether unprece- 

 dented, but from the fact that at New Britain, twenty-five miles north of New 

 Haven, Mr. Burritt, an experienced observer, watched the needle for two hours 

 during the most active period of the same aurora, and could not discern the least 

 change of declination, while the change of declination at New Haven was, as already 

 stated, a whole degree. 2 



1 Annapolis Republican, Jan. 28, 1837. We can hardly avoid suspecting either an error of observa- 

 tion, or a misprint, in a result so unparalleled. — O. 



2 Captain Richardson also reports that in his observations on the auroras of the polar regions, he 

 could discover no effect on the needle. Captain Parry says the same. 



