On the Nature of Things (De Rerum Natura)

move on, and when they like a mighty stream have borne down in any direction, they push things before them and throw them down with repeated assaults, sometimes catch them up in curling eddy and carry them away in swift-circling whirl. Wherefore once and again I say winds are unseen bodies original: "corpora caeca", since in their works and ways they are found to rival great rivers which are of a visible body. Then again we perceive the different smells of things, yet never see them coming to our nostrils; nor do we behold heats nor can we observe cold with the eyes nor are we used to see voices. Yet all these things must consist of a bodily nature, since they are able to affect the senses; for nothing but body can touch and be touched. Again clothes hung up on a shore which waves break upon become moist, and then get dry if spread out in the sun. Yet it has not been seen in what way the moisture of water has sunk into them nor again in what way this has been dispelled by heat. The moisture therefore is dispersed into small particles which the eyes are quite unable to see. Again after the revolution of many years a ring on the finger is thinned on the under side by wearing, the dripping from the eaves hollows a stone, the bent ploughshare of

iron is imperceptibly worn away in the fields, and we see the stone paved streets of the city rubbed down by the feet of the multitude. The brass statues too by the gates show their right hands thinned by the frequent contact of those who salute them as they pass. These then we see are worn away, since they are rubbed down; but what bodies depart at any given moment, the nature of our sight has denied us the power to see. Finally, whatever time and nature add to things by little and little, constraining them to grow in due measure, no man's keenest sight can perceive. Nor again can you see what is wanting, when things grow old by age and decay, nor what bodies perish from things as they are worn away by length of time and the salt sea. Thus nature is always working by unseen bodies.