WHAT THIS WORLD IS MADE OF 



This goes far beyond even the infinitesimal 

 waves in the ether that make what we call light; 

 and these waves were long thought of as the small- 

 est things directly measurable in this world. It was 

 only by knowing the wave-lengths of light that it 

 was possible, at first, to measure the thickness of the 

 soap-bubble's wall. More recently electrical means 

 have been employed also, and the results of the 

 two are in entire accord. With the longest light- 

 waves, those of the red, 1 it is about 800 /u/i from the 

 top of one wave to the next, and even with the 

 shortest visible rays the violet it is nearly 400 pp 

 from fifty to one hundred times the thickness of 

 the soap-bubble's black spot. 



As all this means little to the imagination, we 

 may make a comparison. The huge ocean- waves 

 encountered in a storm are rarely more than five 

 or six hundred feet from crest to crest much less, 

 for example, than the length of the Deutschland. 

 Cast upon a beating sea of light, a boat the size of a 

 soap-bubble's thickness would mean, in compari- 

 son to the waves in an ocean storm, a cockle-shell 

 four or five feet long. 



This is going very far. But we may have perfect- 

 ly continuous layers of a liquid thinner even than 

 this. An interesting instance was found by Lord 



1 See "The World Beyond Our Senses," p. 41. 

 IOQ 



