THE EARTH. 2G3 



Kppearance which is produced in the southern climates by the 

 heat, is there produced by the contrary extreme.' The sea 

 smokes lilie an oven, and a fog arises which mariners call the 

 frvsl smoke. This cutting mist commonly raises blisters on 

 several parts of the body ; and as soon as it is wafted to some 

 colder part of the atmosphere, it freezes to little icy paiticles, 

 which are driven by the wind, and create such an intense cold on 

 land, that the limbs of the inhabitants are sometimes frozen, and 

 di'op off. 



There, also, halos, or luminous circles round the moon, are 

 oftener seen than in any other part of the earth, being formed 

 by the frost smoke ; although the air otherwise seems to be 

 clear A lunar rainbow also is often seen there, though some- 

 what different from that which is common with us ; as it appears 

 of a pale white, striped with gi"ay. In these countries also, the 

 aurora borealis streams with peculiar lustre, and variety of 

 colours.* In Greenland it generally arises in the east, and darts 



1 Paul Egede's History of Greenland. 

 * The aurora borealis may with propriety be disting^uished into two kinds, 

 khe tranquil, and the varying. The tranquil sbines with a mild and steady 

 light, very much resemhling- the clearness of twilight ; and preserres, for u 

 considerable time, the form in which it first appears, %vith little or no variation. 

 The varying aurora is still more remarkable in its appearance, and occasionally 

 exhibits the roost brilliant and rapidly diversified forms. In that region of 

 the air which is directly towards the north, or which str Aches from the north 

 towards the east or west, there appears at first a cloud in the horizon, which 

 rarely rises to the height of 40 degrees. This cloud is sometimes contiguous 

 to the horizon, sometimes detached from it ; in which last case the interme- 

 diate sky appears of a bright blue colour. The cloud occupies a portion of 

 the heavens extending in length from 5 to 100 degrees, and sometimes stiU 

 farther. It is generally white and shining, but sometimes black and thick. 

 Its upper edge is parallel to the horizon, bordered by a long train of light 

 which rises higher in some places than in others. It appears also bent in the 

 form of a bow, or like the segment of a sphere which has its centre consi- 

 derably beneath the horizon; and sometimes a large white or luminous 

 band is visible skirting the superior edge of the black cloud. The dark part 

 of the clond becomes white and luminous when the aurora has shone for 

 eome time, and after it has sent forth several bright and fiery rays. Then 

 from the superior edge of the cloud, there issue rays in the form of jets, 

 wliich are sometimes many, sometimes few in nuinber, sometimes close to- 

 gether, sometimes removed several degrees asunder. These jets diffuse a 

 very brilliant light, as if a luminous or fiery liquor were driven with impetu- 

 osity from a syringe. The jet increases in brightness, and has less bulk at 

 the place where it issues from the cloud ; while it dilates itself and grows dim- 

 mer as it goes farther and farther off. Tlien there arises from a large opeik. 



