126 
NATURE FOR ITS OWN SAKE 
Transpar- 
ency of 
seu color. 
in the Arctic seas, are accounted for in this way. 
But these are mere patches of surface-color in 
isolated regions. ‘The general hue of sea-water 
is controlled largely by the matter of depth. 
It requires a great mass of air-particles to pro- 
duce a blue sky, and it takes a great depth of seas 
water and much reflection from salt-particles to 
produce * the deep blue sea.” Itis safe to say, 
then, that the greatest depths are the bluest, 
that the shallower depths incline to green, and 
the shallowest waters—the waters near shore— 
are the ones that show the browns, reds, or yel- 
lows. 
All of these colors are peculiarly beautiful for 
ayreason we seldom take into consideration— 
namely, their transparency. The ordinary 
colors of nature as shown in grass, flowers, 
trees, fields, mountains, are opaque. The hue 
is on the surface, and is only a veneer—an outer 
coating—so far as our eyes are concerned. But 
the sky in its interminable height and the sea 
in its vast depth are blue by virtue of super- 
imposed layers or strata of transparent sub- 
stances. It is not until stratum has been 
heaped upon stratum in countless numbers that 
the color begins to show. We sce into them as 
into open space, the quality of the color breaks 
