WHAT THIS WORLD IS MADE OF 



spontaneously arranged themselves into symmet- 

 rical groups, most interesting to watch. If this 

 experiment had been made so that these little 

 magnets were suspended in the water instead 

 of being held to a plane surface, so as to em- 

 ploy all three dimensions of space, we might 

 have a very good model of the finer structure 

 of matter. 



If shape, structure, chemic behavior, lie still in 

 obscurity, it is at least clear that the molecules are 

 endowed with tremendous energy. For example, 

 no known pressure can liquefy air at ordinary tem- 

 peratures. Its heat-motion must first be reduced 

 very near to nothing. Again, in order that particles 

 of water may hold together in a drop, in a glass, 

 in the ocean, everywhere they must be attracting 

 each other with great force ; one estimate sets it as 

 equal to three hundred thousand pounds per square 

 inch twenty thousand times ordinary atmospheric 

 pressure. 



Thus far we have kept within the domain of 

 physics, and in saying that the molecules seem to 

 vary but little in size, the reader might infer that 

 they vary little in kind. But here the chemist steps 

 in with other methods to demonstrate the existence 

 of seventy or eighty distinct varieties of molecules 

 elements, he calls them. These vary widely in 



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