BROKEN AND SHADED LIGHT 
29 
scurity and facilitates diffusion, as does a ground- 
glass globe upon a lamp. The result is a vapor- 
like light of marvellous luminosity and great 
beauty. Unfortunately it is not of long duration, 
and here in America it is not often seen. In 
France along the Seine, in England along the 
southern coast, and in Japan it is of common 
occurrence. The so-called ‘‘ white horizon” 
results from a similar set of circumstances. The 
vapor-laden atmosphere of the morning, seen in 
mass as we look toward the horizon, produces 
the white-light effect. Seen in the afternoon 
or at sunset, the same horizon shows rose, lilac, 
or mauve tints, because the vapor particles have 
been superseded, or at least alloyed by the dust 
particles, and the heat is greater. 
But to return to the fog along the ground, as 
goon as it begins to lift it becomes lighter and 
brighter until finally the sun peering through 
from above appears as a silver or pale-yellow disk 
without radiant shafts. The light grows more 
golden as the fog-bank decreases in thickness, 
until at last, the sun having burned its way 
through to the earth, we see the normal light 
of day. The fog then disperses in small patches, 
is evaporated and carried upward by rising cur- 
rents of air, and in a short time has disap- 
Vapor 
lights. 
White 
horizons. 
Fog lights, 
