On the nature of things (books 4 - 6)   

Echoing through groves and hills and forest trees,
Even as he viewed his living flesh entombed
Within a living grave; whilst those whom flight
Had saved, with bone and body bitten, shrieked,
Pressing their quivering palms to loathsome sores,
With horrible voices for eternal death-
Until, forlorn of help, and witless what
Might medicine their wounds, the writhing pangs
Took them from life. But not in those far times
Would one lone day give over unto doom
A soldiery in thousands marching on
Beneath the battle-banners, nor would then
The ramping breakers of the main seas dash
Whole argosies and crews upon the rocks.
But ocean uprisen would often rave in vain,
Without all end or outcome, and give up
Its empty menacings as lightly too;
Nor soft seductions of a serene sea
Could lure by laughing billows any man
Out to disaster: for the science bold
Of ship-sailing lay dark in those far times.
Again, 'twas then that lack of food gave o'er
Men's fainting limbs to dissolution: now
'Tis plenty overwhelms. Unwary, they
Oft for themselves themselves would then outpour
The poison; now, with nicer art, themselves
They give the drafts to others.

BEGINNINGS OF CIVILIZATION

Afterwards,
When huts they had procured and pelts and fire,
And when the woman, joined unto the man,
Withdrew with him into one dwelling place,

Were known; and when they saw an offspring born
From out themselves, then first the human race
Began to soften. For 'twas now that fire
Rendered their shivering frames less staunch to bear,
Under the canopy of the sky, the cold;
And Love reduced their shaggy hardiness;
And children, with the prattle and the kiss,
Soon broke the parents' haughty temper down.
Then, too, did neighbours 'gin to league as friends,
Eager to wrong no more or suffer wrong,
And urged for children and the womankind
Mercy, of fathers, whilst with cries and gestures
They stammered hints how meet it was that all
Should have compassion on the weak. And still,
Though concord not in every wise could then
Begotten be, a good, a goodly part
Kept faith inviolate- or else mankind
Long since had been unutterably cut off,
And propagation never could have brought
The species down the ages.
Lest, perchance,
Concerning these affairs thou ponderest
In silent meditation, let me say
'Twas lightning brought primevally to earth
The fire for mortals, and from thence hath spread
O'er all the lands the flames of heat. For thus
Even now we see so many objects, touched
By the celestial flames, to flash aglow,
When thunderbolt has dowered them with heat.