BROKEN AND SHADED LIGHT 



29 



scurity and facilitates diffusion, as does aground- 

 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 been superseded, or at least alloyed by the dust 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 

 soon 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 



White 

 horizons. 



Fog light* 



