DALTON. 49 



be now had recourse to a microscope and a delicate knife 

 the division may be carried still further ; and it thus seems 

 proved that the' subdivision of the potato ad infinitum is con- 

 ceivable, if our instruments were delicate enough to effect the 

 subdivisions, and our eyes to make them discernible. Thus 

 argued Epicurus and his followers. 



Let us now look at the other side of the argument, illus- 

 trating it by an assumption. Suppose that amongst the un- 

 known things existing in parts of the earth yet unexplored, 

 there should be a lump of new matter found (we may not 

 say a particle) a lump of some definite size as big as a 

 potato, for example. Suppose that lump of new matter should 

 be so very hard that no human means could break, or cut, 

 or otherwise divide it. What then ? It would be indivisible, 

 of course, i uncuttable ;' or, if we choose to adopt a Greek 

 expression, it would be 6 atomic,' this word being a modifi- 

 cation of a (not) and repveiv (to cut) not cuttable, or not 

 divisible in short, ' atomic.' 



So it appears, then, that our ordinary notion of an atom, 

 as being something necessarily small, is only, after all, an 

 indirect notion. That atoms must be small, if they really 

 do exist, is demonstrable, since all matter can be divided to 

 the furthest limits permitted by our means ; and the division 

 might be carried further still, if our means and our senses 

 permitted. But, for anything one knows to the contrary, 

 the potato may be composed of amazingly small indivisible 

 parts; and the hard indivisible parts might each have been 

 tangibly large as large, say, as a potato, as assumed to be the 

 case with the new mineral invoked by hypothesis. Whether 

 large or small, such palpable indivisible masses would have 

 been to all intents and purposes atoms. 



Mark, then ! There lurked a fallacy in the argument 

 of those who denied the possibility of atoms, because a sub- 

 stance (a potato, say) might, as they said, be conceived to 

 be infinitely divisible. This line of illustration by no means 



E 



