CHANGING IDENTITIES 



be strictly similar (hypothesis), then the atomic 

 weights must fall into the strict series of the in- 

 crease of cubes. But evidently such is not the 

 case. 



Therefore, etc. 



PROPOSITION IX. 



The primary spheres composing the molecules 

 of elementary or chemically compound substances 

 are in some places of contact each to two others 

 in the closest possible contact. 



Because any two substances require more room 

 in a vessel before a chemical combination takes 

 place than they do after it has taken place. 



And because every chemical combination evolves 

 heat. 



Therefore, the atoms, or molecules composing 

 the original substances, have come closer together 

 than they were in each respective substance. 



Again, because the smallest subdivision of the 

 resultant compound, which we can perceive, still 

 possesses properties different from either original 

 substance, it is evident that a new identity has 

 been constructed. To this new identity we give 

 the name molecule. 



An examination of the first atom (Prop. VI, 

 B. 2) shows that this form will fit another similar 

 form, and many others that are composed of more 

 than five spheres. Then while every sphere, be- 



45 



