But, if perchance be any that believe The heavier bodies, as more swiftly borne Plumb down the void, are able from above To strike the lighter, thus engendering blows Able to cause those procreant motions, far From highways of true reason they retire. For whatsoever through the waters fall, Or through thin air, must quicken their descent, Each after its weight--on this account, because Both bulk of water and the subtle air By no means can retard each thing alike, But give more quick before the heavier weight; But contrariwise the empty void cannot, On any side, at any time, to aught Oppose resistance, but will ever yield, True to its bent of nature. Wherefore all, With equal speed, though equal not in weight, Must rush, borne downward through the still inane. Thus ne'er at all have heavier from above Been swift to strike the lighter, gendering strokes Which cause those divers motions, by whose means Nature transacts her work. And so I say, The atoms must a little swerve at times-- But only the least, lest we should seem to feign Motions oblique, and fact refute us there. For this we see forthwith is manifest: Whatever the weight, it can't obliquely go, Down on its headlong journey from above, At least so far as thou canst mark; but who Is there can mark by sense that naught can swerve At all aside from off its road's straight line?