58 
NATURE FOR ITS OWN SAKE 
Color 
ch inges 
through at- 
mosphere. 
Season 
changes in 
the blue. 
of Scotland. In no warm country is there such 
clear blue sky as one may see in the northwest 
of America; and if we may believe the descrip- 
tions of Dr. Nansen, the Arctic explorer, this 
blue grows more intense as we move toward the 
poles, until at last it becomes of that violet hue 
seen from mountain-peaks. The Egyptian blue 
is often ‘‘deep” when the air is clear and 
still, but with winds, heat and dryness it takes 
on a warm tone as though it were seen through 
a red dust-veil. <A similar effect may be 
noticed over cities like London, where smoke 
and soot are continually fouling the air. The 
blue has a suffusion of pink or copper-color that 
gives it a hot look. In moist climates like Ger- 
many or Iolland, there are often very clear 
skies, but the moisture particles in the air 
usually tend toward the production of a pale, 
milky whiteness in the blue. Again, in all 
countries of the northern temperate zone the 
purest summer skies are in the months of May 
and June. After these months the hot and 
dry summer begins to pale the blue, and in the 
autumn, when the leaves are changing to gold 
and scarlet, the sky in perfect harmony becomes 
rosy and often opalescent. 
If people are little observant of the blue sky 
