732 THE UNIVERSE. 



ing the long nights of winter, a phenomenon known as the 

 Aurora Borealis or Australis. 



Whilst this lasts the heavens sometimes present the most 

 splendid spectacle. On the black and starry background 

 of the sky we see traced out a vast luminous cupola, or 

 kind of panelled vault, formed of colonnades of stalactites 

 heaped together and pendant, and which, suspended in the 

 clouds, reflect the brightest hues of the rainbow. Some- 

 times they resemble fireworks, which dart their sheets of 

 flame in every direction, and seem to set on fire the hori- 

 zon, forming one of the most imposing spectacles it is pos- 

 sible to enjoy amid the ice of the north. 



