78 



THE DESERT 



heavy foliage. The vegetation of the desert is 

 so slight that practically the whole surface of 

 the sand acts as a reflector ; and it is this, rather 

 than the sun ? s intensity, that causes the great 

 body of light. The white roads in Southern 

 France, for the surface they cover, are more 

 glaring than any desert sands ; and the sunlight 

 upon snow in Minnesota or New England is 

 more dazzling. In certain spots where there 

 are salt or soda beds the combination of heat 

 and light is bewildering enough for anyone ; 

 but such places are rare. White is something 

 seldom seen on desert lands, and black is an 

 unknown quantity in my observations. Even 

 lava, which is popularly supposed to be as black 

 as coal, has a reddish hue about it. Everything 

 has some color even the air. Indeed, we shall 

 not comprehend the desert light without a mo- 

 mentary study of this desert air. 



The circumambient medium which we call 

 the atmosphere is to the earth only as so much 

 ground-glass globe to a lamp something that 

 breaks, checks, and diffuses the light. We have 

 never known, never shall know, direct sunlight 

 that is, sunlight in its purity undisturbed by 

 atmospheric conditions. It is a blue shaft fall- 

 ing perfectly straight, not a diffused white or 



