NATURE FOR ITS OWN SAKE 
The cirrus. 
Whiteness 
of the cir- 
rus. 
usual elevation is not so great. Apparently it 
stands still in thin wisps and curls against the 
blue, but in reality it is a rapid traveller with 
the wind, and sometimes reaches so great 2 ve- 
locity as ninety miles an hour. It is not a large 
cloud and in form is curled like hair, is fibrous, 
or perhaps feathery. At times it is streaked 
across the sky in a light film somewhat like the 
Milky Way, but more frequently it is in small, 
thin patches. It has also many patterns that 
resemble stripes, tails, plumes, and wings, but 
they are all diaphanous and film-like. When 
it appears in streaks and lines these are usually 
parallel to the wind, and are commonly spoken 
of as ‘‘ mares’-tails,” ‘“ goats’-hair,” or ‘ cats’- 
tails.” These clouds often move in irregular, 
straggling groups. There may be only a few 
straw-like wisps, and then again the upper space 
may be spattered with them. Too thin and 
nebulous as a general thing to show shadows, 
they are the brightest of all the receivers and 
reflectors of light. This may be for two rea- 
sons. First, they are higher than any other 
clouds and receive a more powerful light from 
the sun because of the clearness and thinness of 
the air in which they drift ; secondly, they are 
ice-clouds, that is, made up of needles of ice, 
