MECHANISM OF NATURE 



But since there has been a reduction in size, 

 something else may now fill a part of the space 

 occupied by the ball when it was heated to 1,000 

 degrees. 



But this is impossible if all the space was occu- 

 pied by iron. (Axiom III.) 



Consequently, there were within the space occu- 

 pied by the iron ball spaces which were not filled 

 by the iron. And since this may be proven with 

 the smallest possible amount of iron, and with any 

 known substance under greatly varying degrees of 

 heat, therefore, all bodies directly perceptible to 

 our senses are composed of particles. 



PROPOSITION VI. 



The atoms composing a solid body are not round, 

 but they are interlocked and in actual contact one 

 with another. 



Let a bar of iron be heated. Then for every 

 degree of heat the bar will expand a certain 

 amount, and the expansion will be uniform 

 through many degrees. The space between the 

 atoms increases in size just so much for every 

 pound of coal burnt in heating the iron. Yet if the 

 particles were in the first place apart, the heat 

 would have to act on them through the medium of 

 ether. 



But any force acting through the medium of 

 ether cannot rationally be supposed to act equally 



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