recently witnessed at Hull. 



51 



which extended through the whole length of the curve. These 

 immense flashes reached an altitude of 80° or 90°, and were 

 often divided into numbers of square portions, or flashes, 

 separated by broad dark lines. This singular phenomenon 

 I should judge to be owing to the intervention of patches of 

 dense vapour between me and the aurora; and, as not a cloud 

 was visible during the interval between the flashes, and as the 

 stars preserved their brilliancy, the height of the aurora must 

 have been immense. 



As a diagram, however rough, excels description in these 

 matters, I add a slight sketch (j%. 22.) of the appearance 

 when the square masses were given off. 



I think the exhibition was the most splendid about 10 p.m., 

 although it continued very beautiful till after 2 a. m. There 

 was not the slightest corresponding appearance in the south, 

 nor could I distinguish any sound I could attribute to the 

 aurora : in fact, the latter is perhaps hardly to be expected, 

 as the mean distance of the aurora from the earth, as cal- 

 culated from the observations of twenty different philosophers 

 in the same century, is, according to Sir Richard Phillips, 

 500 miles; the distance observed varying from 100 to 1000 

 miles. 



With respect to the very remarkable changes in the weather, 

 and especially in the temperature, which immediately fol- 

 lowed this certainly uncommon exhibition of the aurora in 

 these latitudes, and which I am about to detail, a large share, 

 in the absence of any other known cause, may fairly be attri- 

 buted to this phenomenon. During the night the temperature 

 fell to 34?°, being the lowest degree of cold I have registered 



hope soon to see the matter fully explained, as Captain Ross (whom I had 

 the pleasure of seeing immediately on his arrival at Hull, after his long 

 absence and perilous adventures) himself informed me he jiad obtained 

 ample and satisfactory information respecting it and its causes. 



E 2 



