378 ACCOUNT OF THE ARCTIC REGIONS. 



cold weather, objects on the horizon, when viewed 

 with a high magnifier, appear affected with a per- 

 petual tremor ; whence, the contemplation of dis- 

 tant objects is accomplished as perfectly with a good 

 pocket glass, as with the best telescope. This tre- 

 mulous motion, is evidently produced by the quan- 

 tity of delicate icy crystals, which, in very low tem- 

 peratures, are almost always seen floating in the 

 air. 



The general obscurity of the atmosphere, arising 

 from clouds or fogs, is such, that the sun is frequent- 

 ly invisible during several successive days. At such 

 times, when the sun is near the northern tropic, 

 there is scarcely any sensible variation in the quan- 

 tity of light, from noon to midnight. Hence, when 

 the sailors have been long abroad in the boats, or so 

 fidly engaged as to be unable to mark the progress 

 of time, the inquiry. Whether it be day or night, 

 is not unfrequent. 



There is nothing remarkable in the appearance of 

 the sun at midnight, excepting, that when its alti- 

 tude is very small, it may be viewed with the naked 

 eye, without producing any painful sensation ; but 

 when it is more than four or five degrees above the 

 horizon, it generally appears as effulgent as with the 

 same elevation in Britain. The force of the sun's 

 rays is sometimes remarkable. Where they fall up- 

 on the snow-clad surface of the ice or land, they are, 

 in a great measure, reflected, without producing any 



