LIGHT WAVES 



325 



The waves in wireless vary from a few feet in length to over 

 a mile. 



The diagram shows the ether waves used for wireless, then a 

 space of vibration about which we know nothing, as we have no 

 instrument delicate enough to measure them. In the next space are 

 waves of heat which we feel but do not see. Next is a space where 

 the waves affect the optic nerve, and we see. These are called light 

 waves. As the number of vibrations increases, there are created 

 ether waves which in photography produce chemical changes and also 



12 OCTAVES OF- 



ETHER WAVES USED 



IN WIRELESS 



5 OCTAVES OF 



ETHER WAVES 



UNKNOWN 



7 OCTAVES OF 

 ETHER WAVES 

 PRODUCING HEAT 



I OCTAVE OF^^TOCTAVESOF 



LI GHT WAVES ETH ER WAVES 



KNOWN AS ULTRAVIOLET 



FIG. 194. 



kill bacteria. These vibrations cause the ultra-violet rays. Beyond 

 this space the vibrations of ether are entirely unknown. 



Transparent, Translucent and Opaque Objects. When light 

 passes through a substance without being diffused we are able to 

 see objects through the substance, which is said to be transparent. 



When light passes through a substance, like paper or ground 

 glass, and we are unable to see objects through it, the substance is 

 said to be translucent. 



A substance which will not permit transmission of light through 

 it is said to be opaque. 



Shadows. When rays of light are cut off by an interposed body, 

 a shadow is formed usually representing in silhouette the form of 

 the interposed body. 



Our night is caused by the shadow of the earth. The sun is 

 shining on one side and the rays of light are unable to illuminate 

 the other side of the earth. The eclipse of the moon is caused by 

 the shadow of the earth touching the moon's surface. Sometimes 

 the moon comes between the sun and the earth. The moon's shadow 



