NATURE AND NATURAL HISTORY 



result of a chill or a fall in temperature. In these 

 mountain valleys, where the sky is clear and the air 

 still, a fog is pretty sure to form during the night. 

 The colder air flows down into the valley and its 

 moisture is condensed into fog. 



Now at a quarter after nine o'clock the fog has be- 

 come a mere wraith. It is forming a thin, frail stra- 

 tum above the valley beneath which I can see that 

 the air is clear, save a bluish haze which will linger 

 a little while after all signs of fog have vanished. 



The fog in the valley is only the phenomenon of 

 the dew on a different scale. There is no dew on a 

 windy or cloudy night, or during times of drought. 

 Such things set one to thinking about the circuit 

 of the waters how many forms this element 

 assumes, and how much depends upon it from 

 the earth to the clouds, through the agency of the 

 sun, from the clouds to the earth in the rains and 

 the dews, from the earth to the sea again through 

 the channels of streams and rivers. On this round 

 it figures in the rainbow, frowns or flushes in the 

 clouds, glances like a diamond in the dewdrop, 

 courses through the cells of plants and trees, and 

 through the heart and veins of man, and of all ani- 

 mal life terrible in floods and waves, sublime in 

 the great cataracts, a bridal veil in the mountain 

 waterfalls, a magic mirror in placid lakes and rivers, 

 transporting, transforming; a ministering angel at 

 one time, a destroying demon at another, the chief 

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