MECHANISM OF NATURE 



other element is an increase of the number of 

 spheres held by the heavier atom in its own con- 

 stitution. 



But an indivisible sphere cannot conform to the 

 outline of any other form, but its own identical 

 form; therefore, a form assumed by four spheres 

 cannot strictly be repeated by any other number 

 of indivisible spheres. 



But a simple laying together of spheres of any 

 uniform diameter in closest possible contact affords 

 the easiest and surest proof. 



Therefore, etc. 



PROPOSITION VIII. 



The increase of form in the last subdivision of 

 substance is an approximation and cannot be an 

 absolute recurrence of the same form. 



Because all substances are built up of primary 

 spheres. (Prop. XIX, B. 1). And because every 

 addition of spheres to a form built up of spheres 

 produces a new form. (Prop. VII, B. 2). There- 

 fore, one form cannot strictly be the enlargement 

 of another identical form. 



There may be great similarity in forms, larger 

 and smaller the general outline may be repeated. 

 But there is a well defined limit, where no more 

 spheres can be added, each to two others in the 

 closest possible contact. 



Let it be otherwise and let the form of atoms 

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