342 GENERAL SCIENCE 



before. This phenomenon is known as diffusion, or diffused reflection. 

 No images are formed as result of it. 



Some of these image positions are such that a screen placed there 

 will show the image upon it. One could lay hold of the image by 

 grasping it in the hand if it were only something tangible. Such 

 images are said to be real. Virtual images are those where this is 

 impossible, their positions being apparent and not real. The light 

 does not even get where the virtual image seems to be. 



In plane mirrors the virtual image of an object is so located that 

 every point in the image is as far back of the reflecting surface as the 

 corresponding point of the object is in front of it, and a line connecting 

 these two points forms a right angle with the mirror surface. 



COLOR PHENOMENA 



In order to enjoy the natural colorings of sky and cloud 

 and landscape, and the marvelous combinations and blend- 

 ings of color in flowers and in the plumage of birds, it is 

 neither necessary to make a study of Physics nor to under- 

 stand the theories by which scientists explain color phe- 

 nomena. One may become skilled as a painter of land- 

 scapes, of historic scenes, or of portraits; he may be a 

 master in the art of dyeing, and produce the brilliancy 

 and variety seen in the various fabrics, and at the same 

 time know nothing of the scientific explanation of these 

 color effects. But the explanations of the nature of light and 

 color as given in Physics simplify what otherwise would re- 

 main an inexplicable and bewildering number of unrelated 

 phenomena. The teachings of science concerning color phe- 

 nomena is a good illustration of how advancement in learn- 

 ing by individuals and by mankind in general becomes pos- 

 sible through the efforts made by scientists to ascertain the 

 nature and meaning of the various phenomena of life. 



When a beam of sunlight is passed through a glass prism, 

 and into a room from which all other light has been excluded, 

 it is possible by a proper adjustment of the prism to get on 

 a screen or a white wall a band of overlapping colors like 



