GREEK SCIENCE IN EARLY ATTIC PERIOD 



things that are separated, for water is separated from 

 the clouds, and earth from the water; and from the 

 earth stones are condensed by the cold, and these are 

 separated farther from the water." Here again the 

 influence of heat and cold in determining physical 

 qualities is kept pre-eminently in mind. The dense, 

 the moist, the cold, the dark are contrasted with the 

 rare, the warm, the dry, and bright ; and the formation 

 of stones is spoken of as a specific condensation due to 

 the influence of cold. Here, then, we have nearly all 

 the elements of the Daltonian theory of atoms on the 

 one hand, and the nebular hypothesis of Laplace on 

 the other. But this is not quite all. In addition to 

 such diverse elementary particles as those of gold, 

 water, and the rest, Anaxagoras conceived a species 

 of particles differing from all the others, not merely 

 as they differ from one another, but constituting a 

 class by themselves; particles infinitely smaller than 

 the others; particles that are described as infinite, 

 self -powerful, mixed with nothing, but existing alone. 

 That is to say (interpreting the theory in the only 

 way that seems plausible), these most minute par- 

 ticles do not mix with the other primordial particles 

 to form material substances in the same way in which 

 these mixed with one another. But, on the other 

 hand, these "infinite, self -powerful, and unmixed" 

 particles commingle everywhere and in every sub- 

 stance whatever with the mixed particles that go to 

 make up the substances. 



There is a distinction here, it will be observed, 

 which at once suggests the modern distinction between 

 physical processes and chemical processes, or, putting 



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