THE WORLD'S WONDERS. 697 



The periodical return of the phenomena indicates such a position ; 

 so, too, its rapid motion, which exceeds that of light or elec- 

 tricity, and the extent of surface over which the phenomena is 

 seen at the same time." 



Mock moons and paraselense, which are a rare sight even in the 

 Arctic zone, are due to electrical disturbance of a misty atmos- 

 phere. The paraselenes are luminous rings surrounding the moon, 

 and are multiplied by refraction until three, and sometimes even 

 four, circles are seen impinging one another. Within the centre 

 of each circle the moon appears, from which radiates four spears 

 of light, light spokes to a wheel, and at the points where the 

 spears touch the circle a mock moon is seen, thus affording at 

 once a novel and beautiful view. 



COLORED SNOW. 



THERE is almost perpetual snow in the Polar regions, but it 

 does not fall to such great depth there as in the North Temperate 

 zone. But the most striking peculiarity in the fall of snow 

 within the Arctic circle, is found in the fact that it is often deeply 

 colored, green, red, yellow and black, red being the color most 

 commonly seen. The black color is produced by the snow being 

 impregnated with a dust of carbon and iron, either from the 

 eruptions of volcanoes or from meteors. The other colors are 

 due to the presence of microscopic organisms, described by Dr. 

 Wollaston as minute spherical globules, having a transparent cov- 

 ering, and divided into seven or eight cells, filled with a red oily- 

 like liquid, insoluble in water. Girodchantraus describes these 

 as plants, while Bauer demonstrated that they are a fungous 

 growth. Robert Brown says they are algose, water plants or sea- 

 weeds. Recent investigation confirms the theory that these colors 

 are produced bv vegetable growth, and that the several colors 

 are due to the ripening stages of the algoae. Ehrenburg main- 

 tains that red snow receives its coloring not only from vegetable 

 spores, but from an animalcule also, to which he gave the name 

 Philodina roseola. 



