Nor need we be surprised at the doctrine that the atoms, so all-powerful in
the formation of things, are themselves invisible. The same is true of the
forest-rending blasts, the ‘viewless winds’ which lash the waves and
overwhelm great fleets. There are odours also that float unseen upon the
air; there are heat, and cold, and voices. There is the process of
evaporation, whereby we know that the water has gone, yet cannot see its
vapour departing. There is the gradual invisible detrition of rings upon the
finger, of stones hollowed out by dripping water, of the ploughshare in the
field, and the flags upon the streets, and the brazen statues of the gods
whose fingers men kiss as they pass the gates, and the rocks that the salt
sea-brine eats into along the shore.
That there is Empty Space or Void he proves by all the varied motions on
land and sea which we behold; by the porosity even of hardest things, as we
see in dripping caves. There is the food also which disperses itself
throughout the body, in trees and cattle. Voices pass through closed doors,
frost can pierce even to the bones. Things equal in size vary in weight; a
lump of wool has more of void in it than a lump of lead. So much for
Lucretius.