THE WORLD BEYOND OUR SENSES 



smell, outside of any native sense, there lies an 

 unseen, unheard, unfelt universe, whose fringe we 

 are just beginning to explore. 



A flash, so to speak, from this supra - sensual 

 world came with the discovery of the Rontgen 

 rays. It is now eight years since we first learned 

 that we may look straight into our bodies and see 

 our bones, and that in this light even great books 

 of philosophy become quite clear transparent 

 even; and the wonder has a little died. But they 

 are still called X-rays, for we still do not know 

 what they are or where they belong. 



What is tolerably sure is that there is a wide 

 gap between the Rontgen light and common light, 

 and the gap seems to lie far above the shortest 

 little light- waves hitherto known. It is in the 

 form of minute waves, more than microscopic un- 

 dulations in the all-pervading ether of space, that 

 physicists nowadays conceive light. And it is a dif- 

 ference in wave-length, merely, that makes what 

 we call color. The red and the orange are long 

 waves, not more than from 33,000 to 40,000 to a 

 linear inch; the indigo and violet waves are only 

 about half as long from 50,000 to 60,000 per inch. 

 In between are the yellow, green, blue, and all their 

 insensible gradations. 



It was Sir Isaac Newton's first notable discovery 

 that white light is a compound of all the others, 



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