A HISTORY OF SCIENCE 



visibly small, as infinite in number, and as made up of 

 an indefinite number of kinds one for each distinctive 

 substance in the world. But precisely the same post- 

 ulates are made of the atom of Democritus. These 

 also are invisibly small; these also are infinite in num- 

 ber; these also are made up of an indefinite number 

 of kinds, corresponding with the observed difference 

 of substances in the world. "Primitive seeds," or 

 "atoms," were alike conceived to be primordial, un- 

 changeable, and indestructible. Wherein then lies the 

 difference? We answer, chiefly in a name; almost 

 solely in the fact that Anaxagoras did not attempt to 

 postulate the physical properties of the elements be- 

 yond stating that each has a distinctive personality, 

 while Democritus did attempt to postulate these prop- 

 erties. He, too, admitted that each kind of element 

 has its distinctive personality, and he attempted to 

 visualize and describe the characteristics of the per- 

 sonality. 



Thus while Anaxagoras tells us nothing of his ele- 

 ments except that they differ from one another, De- 

 mocritus postulates a difference in size, imagines some 

 elements as heavier and some as lighter, and conceives 

 even that the elements may be provided with project- 

 ing hooks, with the aid of which they link themselves 

 one with another. No one to-day takes these crude 

 visualizings seriously as to their details. The sole ele- 

 ment of truth which these dreamings contain, as dis- 

 tinguishing them from the dreamings of Anaxagoras, 

 is in the conception that the various atoms differ 

 in size and weight. Here, indeed, is a vague fore- 

 shadowing of that chemistry of form which began 



168 



