60 
NATURE FOR ITS OWN SAKE 
Trans- 
mitted 
light. 
Sky lights 
on theearth. 
which may, perhaps, be cleared up by some such 
explanation as this: Glancing up at the sky our 
eyes look inevitably into the shadows of air par- 
ticles ; the light that comes to us is transmitted 
through and between the particles. Glancing 
down at the paper, we are looking into the high 
lights of the paper instead of shadows; the 
light is now reflected instead of transmitted. 
It is because of the coloring of the blue, and 
the transmission of light in countless infinitesi- 
mal points through it that we fail to appreci- 
ate its luminosity, and yet next to the sun and 
its reflections it is the most luminous phenom- 
enon in the universe. It blinds the light of the 
stars so that we fail to see them in the daytime, 
and even the moon looks pale and wan beyond 
it until the sun has gone down and the hght 
fades out of the atmospheric canopy. Upon 
the earth its effect is equally apparent. The 
snow reflects the light of the blue sky like the 
sheet of paper; and the white daisies of the 
meadow, the white foam of the sea, and the sil- 
ver flash from still waters are but reflections of 
it. From mountain-heights at twilight one may 
see below in the valley the thread-like river, the 
white farm-houses, and the fields of yellow grain 
showing like spots of light upon the shadowed 
