120 
NATURE FOR ITS OWN SAKE 
Wave lines. 
North 
Atlantic 
waves. 
and such thicknesses are infrequent, if, indeed, 
not impossible. 
The lines of a wave made by light-and-shade 
and the variation of color are somewhat de- 
pendent upon wave motion. The swell of 
the Southern seas has about the same lines as 
the smaller rolls of a Dakota prairie. The 
horizontal ridge and its corresponding valley 
are distinctly marked, light-and-shade and color 
play all along them, and the heavens above 
are rolled and unrolled from them in long, 
flashing reflections. As soon as the sur- 
face is broken by wind the lines are blurred, 
and the reflection is lost in local hue, though 
each little wave continues to throw off from 
itself the tiny reflection of hght and color, like 
a portion of a broken mirror. The general 
form and heave of the wave are not lost; its 
surface only is changed. The waves on the 
North Atlantic are quite different from this 
tropical undulation. They are shorter, sharper, 
more ragged in surface, and they have a cross- 
blow tumble and toss about them that some- 
times defy the line and make only flashing 
light and color possible. In heavy and steady 
winds they heap up in enormous ridges, follow- 
ing each other, file upon file, like other waves, 
