Lucretius, De Rerum Natura
William Ellery Leonard, Ed.

     But now I will unfold
At last how yonder suddenly angered flame
Out-blows abroad from vasty furnaces
Aetnaean. First, the mountain's nature is
All under-hollow, propped about, about
With caverns of basaltic piers. And, lo,
In all its grottos be there wind and air-
For wind is made when air hath been uproused
By violent agitation. When this air
Is heated through and through, and, raging round,
Hath made the earth and all the rocks it touches
Horribly hot, and hath struck off from them
Fierce fire of swiftest flame, it lifts itself
And hurtles thus straight upwards through its throat
Into high heav'n, and thus bears on afar
Its burning blasts and scattereth afar
Its ashes, and rolls a smoke of pitchy murk
And heaveth the while boulders of wondrous weight-
Leaving no doubt in thee that 'tis the air's
Tumultuous power. Besides, in mighty part,
The sea there at the roots of that same mount
Breaks its old billows and sucks back its surf.
And grottos from the sea pass in below
Even to the bottom of the mountain's throat.
Herethrough thou must admit there go...
     . . . . . .
And the conditions force [the water and air]
Deeply to penetrate from the open sea,
And to out-blow abroad, and to up-bear
Thereby the flame, and to up-cast from deeps
The boulders, and to rear the clouds of sand.
For at the top be "bowls," as people there
Are wont to name what we at Rome do call
The throats and mouths.