BEFLECTION OF LIGHT. 301 



SECTION I. 



REFLECTIOX OF LIGHT. 



Tnjat ocmrs ^^3. When rays of li^ix^t fall upon any sur- 

 nponauy'^M! ^^^e, tliGy mav be reflected, absorbed, or 

 '^***' transmitted. Only a portion of the light, 



however, "which meets any surface is reflected, the remain- 

 der being absorbed, or transmitted. 



When does a 654. When the portion of light reflected 

 vwteand^en ^^om anv surface, or point of a surface, to the 

 ^'^^ eye is considerable, such surface, or point, ap- 



pears -white ; when very little is reflected, it appears dark- 

 colored; but when all, or nearly all the rays are absorbed, and 

 none are reflected back to the eye, the surface appears black. 



Thus, chjwcoal 13 black, because it absorbs all the light which falls upon it, 

 and reflects none. Such a bodj can not be seen unless it is situated near 

 other bodies which reflect light to it. 



According to a variation in the manner of reflecting light, the same surface 

 •which appears whits to an eye in one position, may appear to be black from 

 another point of view, as frequently happens in the case of a mirror, or of 

 any other bright, or reflecting surface. 



■What are good Dcusc bodics, particularly smooth metals, 

 re^flectors of reflect light most perfectly. The reflecting 

 power of other bodies decreases in proportion 

 to their porosity. 



How are non- ^^5. All bodics uot in thcmselves luminous, 

 J^XTd ^^^' become visible by reflecting the rays of light. 



It is by the irregular reflection of light that most objects in 

 nature are rendered visible ; since it is by rays which are dispersed from re- 

 flecting surfaces, irregularly and in every direction, that bodies not exposed 

 to direct light are illuminated. If light were only reflected regularly from the 

 surface of non-luminous bodies, we should see merely the image of the lumin- 

 ous object, and not the reflecting surface.* In the day-time, the image of the 

 Bun would be reflected from the surface of all objects around us, as if they 

 ■were composed of looking-glass, but the objects themselves would be invisi- 

 ble. A room in which artificial li:rhts were placed would reflect these lights 

 from the walls and other objects as if they were mirrors, and all that would, 

 be visible would be the multiplied reflection of the artificial lights. 



• In a very good mirror we scarcely perceive tlie reflecting surface interyening betireen 

 ns and the images it shows us. 



