228 NATURAL APPEARANCES 



stronger light, spreading into columns, and altering 

 slowly into ten thousand different shapes, varying 

 their colours, from all the tints of yellow, to the most 

 obscure russet. They often cover the whole hemi- 

 sphere, and then make the most brilliant appearance. 

 Their motions, at these times, are most amazingly 

 quick, and they astonish the spectator with the rapid 

 changes of their form. They break out in places 

 where none were seen before, skimming briskly 

 along the heavens. * On a sudden they are extin- 

 guished, and lea^e behind a uniformly dusky tract. 

 This again is illuminated in the same manner, and 

 as suddenly left a dull blank. In certain nights they 

 assume the appearance of vast columns, on one side 

 of the deepest yellow, on the other declining away 

 till it becomes undistinguished from the sky. They 

 have generally .a strong, tremulous motion, from end 

 to end, which continues till the whole vanishes. In 

 a word, we, who only see the extremities of these 

 northern phenomena, have but a faint idea of their 

 splendour and their motions. 



In Siberia there is one species of the aurora bore- 

 alis, which regularly appears between the north-east 

 and east, like a luminous rainbow, with numbers of 

 columns of light radiating from it. Beneath the arch 

 is a darkness, through which the stars appear with 

 some brilliancy. There is another kind, which be- 

 gins with certain insulated rays from the north, and 

 others from the north-east, They augment little by 

 little till th(\\ fill the whole sky, and form a splen- 

 dour of colours rich as gold, rubies, and emeralds ; 



