Lucretius, De Rerum Natura
William Ellery Leonard, Ed.

     Now what the speed to matter's atoms given
Thou mayest in few, my Memmius, learn from this:
When first the dawn is sprinkling with new light
The lands, and all the breed of birds abroad
Flit round the trackless forests, with liquid notes
Filling the regions along the mellow air,
We see 'tis forthwith manifest to man
How suddenly the risen sun is wont
At such an hour to overspread and clothe
The whole with its own splendour; but the sun's
Warm exhalations and this serene light
Travel not down an empty void; and thus
They are compelled more slowly to advance,
Whilst, as it were, they cleave the waves of air;
Nor one by one travel these particles
Of the warm exhalations, but are all
Entangled and enmassed, whereby at once
Each is restrained by each, and from without
Checked, till compelled more slowly to advance.
But the primordial atoms with their old
Simple solidity, when forth they travel
Along the empty void, all undelayed
By aught outside them there, and they, each one
Being one unit from nature of its parts,
Are borne to that one place on which they strive
Still to lay hold, must then, beyond a doubt,
Outstrip in speed, and be more swiftly borne
Than light of sun, and over regions rush,
Of space much vaster, in the self-same time
The sun's effulgence widens round the sky.
     . . . . . .
Nor to pursue the atoms one by one,
To see the law whereby each thing goes on.
But some men, ignorant of matter, think,
Opposing this, that not without the gods,
In such adjustment to our human ways,
Can nature change the seasons of the years,
And bring to birth the grains and all of else
To which divine Delight, the guide of life,
Persuades mortality and leads it on,
That, through her artful blandishments of love,
It propagate the generations still,
Lest humankind should perish. When they feign
That gods have stablished all things but for man,
They seem in all ways mightily to lapse
From reason's truth: for ev'n if ne'er I knew
What seeds primordial are, yet would I dare
This to affirm, ev'n from deep judgment based
Upon the ways and conduct of the skies-
This to maintain by many a fact besides-
That in no wise the nature of the world
For us was builded by a power divine-
So great the faults it stands encumbered with:
The which, my Memmius, later on, for thee
We will clear up. Now as to what remains
Concerning motions we'll unfold our thought.