And lest the winds blew back again, no force
Could rein things in nor hold from sure career
On to disaster. But now because those winds
Blow back and forth in alternation strong,
And, so to say, rallying charge again,
And then repulsed retreat, on this account
Earth oftener threatens than she brings to pass
Collapses dire. For to one side she leans,
Then back she sways; and after tottering
Forward, recovers then her seats of poise.
Thus, this is why whole houses rock, the roofs
More than the middle stories, middle more
Than lowest, and the lowest least of all.

Arises, too, this same great earth-quaking,
When wind and some prodigious force of air,
Collected from without or down within
The old telluric deeps, have hurled themselves
Amain into those caverns sub-terrene,
And there at first tumultuously chafe
Among the vasty grottos, borne about
In mad rotations, till their lashed force
Aroused out-bursts abroad, and then and there,
Riving the deep earth, makes a mighty chasm--
What once in Syrian Sidon did befall,
And once in Peloponnesian Aegium,
Twain cities which such out-break of wild air
And earth's convulsion, following hard upon,
O'erthrew of old. And many a walled town,
Besides, hath fall'n by such omnipotent
Convulsions on the land, and in the sea
Engulfed hath sunken many a city down
With all its populace. But if, indeed,
They burst not forth, yet is the very rush
Of the wild air and fury-force of wind
Then dissipated, like an ague-fit,
Through the innumerable pores of earth,
To set her all a-shake--even as a chill,
When it hath gone into our marrow-bones,
Sets us convulsively, despite ourselves,
A-shivering and a-shaking. Therefore, men
With two-fold terror bustle in alarm
Through cities to and fro: they fear the roofs
Above the head; and underfoot they dread
The caverns, lest the nature of the earth
Suddenly rend them open, and she gape,
Herself asunder, with tremendous maw,
And, all confounded, seek to chock it full
With her own ruins. Let men, then, go on
Feigning at will that heaven and earth shall be
Inviolable, entrusted evermore
To an eternal weal: and yet at times
The very force of danger here at hand
Prods them on some side with thi