CHEMISTRY ' 



hard, impenetrable, moveable Particles, of such Sizes and 

 Figures, and with such other Properties, and in such Propor- 

 tion to Space, as more conduced to the End for which He 

 form'd them; and that these primitive Particles being Solids, 

 are incomparably harder than any porous Bodies compounded 

 of them; even so very hard as never to wear or break in 

 pieces: No ordinary power being able to divide what God 

 made one in the first Creation. While the Particles continue 

 entire, they may compose Bodies of one and the same Nature 

 and Texture in all Ages: But should they wear away, or 

 break in pieces, the Nature of Things depending on them 

 would be changed. Water and Earth composed of old worn 

 Particles and Fragments of Particles, would not be of the 

 same Nature and Texture now, with Water and Earth com- 

 posed of entire Particles in the Beginning. And therefore 

 that Nature may be lasting, the changes of corporeal Things 

 are to be placed only in the various Separations and new Asso- 

 ciations and Motions of these permanent Particles : compound 

 Bodies being apt to break, not in the midst of solid Particles, 

 but where those Particles are laid together and only touch in 

 a few Points. 



"It seems to me farther, that these Particles have not 

 only a Vis inertia, accompanied with such passive Laws of 

 Motion as naturally result from that Force, but also that they 

 are moved by certain Principles (Energies), such as that of* 

 Gravity, and that which causes Fermentation, and the Cohe- 

 sion of Bodies. These Principles I consider not as occult 

 Qualities, supposed to result from the specifick Forms of 

 Things, but as general Laws of Nature, by which the Things 

 themselves are form'd ; their Truth appearing to us by Phseno- 

 mena, though their Causes be not yet discover'd. For these 

 are manifest Qualities, and their Causes only are occult. ..." 



The latest form of the atomic theory is in keeping with 

 the theoretical definition of homogeneous substance required 

 by the theory of certain Greek thinkers promulgated 2500 



