Page:Popular Science Monthly Volume 44.djvu/372

360 surface receiving light, every little grain and fiber acting as a reflector to send it out again. Reflection and re-reflection are taking place with enormous rush and intricacy. But the extent of complication is not yet reached. These various lights are not all white. Each substance has its effect upon the light that it reflects. Some of the light undulations are absorbed, and those reflected give the effect of color characteristics of the object. The colored lights are then flashing back and forth, continually changing as they leave the different surfaces. Neither is this a complete statement of the situation. Each surface is illuminated by a variety of colored lights, depending upon the surfaces opposite it. The color of any one material depends upon the color of the light striking it, as well as upon its own nature. Hence possibly none of the surfaces in the street are seen in their true tones, the hues belonging to them when illuminated by pure white sunlight. They are slightly off color, modified by the colored lights that strike them. All this wonderful play of lights darting across the street is put in action by the steady, powerful, pure white flood of light coming from the sun.

It may be questioned why this condition of affairs is not more noticeable. Why are not the bright hues of the rainbow seen in all directions? The absence of brilliant coloring is briefly accounted for by the large amount of surface reflection taking place, through which we see objects as if a gray glazing had been washed over them.

However, conditions will occur when there is a very noticeable flush of color cast over objects which is not their normal hue, and it can be traced to the predominating influence of some one of the reflecting surfaces. Occasionally most striking effects of this character are seen during the sunset hour. Sun-illumined clouds are in the west holding their bright color when all other sources of light in sky and earth are waning. The predominating power of their colored light is enough to make a modest little sunset in the east, and the sky there will glow with a soft tint sympathetic with the display in the opposite part of the heavens. The western sky may even give a glamour of colored light to the landscape, casting a weird, strange effect over meadow and hillside, ere they disappear in the darkness.

Those who use colored parasols understand perfectly the result, if not the theory, when the lining of the parasol is selected so as to add to natural charms by casting a soft flush of color over the complexion.

But illustration of the influence of the effect of surfaces upon