Then canst thou know their mighty masses, then Canst view their caverns, as if builded there Of beetling crags; which, when the hurricanes In gathered storm have filled utterly, Then, prisoned in clouds, they rave around With mighty roarings, and within those dens Bluster like savage beasts, and now from here, And now from there, send growlings through the clouds, And seeking an outlet, whirl themselves about, And roll from 'mid the clouds the seeds of fire, And heap them multitudinously there, And in the hollow furnaces within Wheel flame around, until from bursted cloud In forky flashes they have gleamed forth.
Again, from following cause it comes to pass That yon swift golden hue of liquid fire Darts downward to the earth: because the clouds Themselves must hold abundant seeds of fire;For, when they be without all moisture, then They be for most part of a flamy hue And a resplendent. And, indeed, they must Even from the light of sun unto themselves Take multitudinous seeds, and so perforce Redden and pour their bright fires all abroad.
And therefore, when the wind hath driven and thrust, Hath forced and squeezed into one spot these clouds, They pour abroad the seeds of fire pressed out, Which make to flash these colours of the flame.
Likewise, it lightens also when the clouds Grow rare and thin along the sky; for, when The wind with gentle touch unravels them And breaketh asunder as they move, those seeds Which make the lightnings must by nature fall;At such an hour the horizon lightens round Without the hideous terror of dread noise And skiey uproar.
To proceed apace, What sort of nature thunderbolts possess Is by their strokes made manifest and by The brand-marks of their searing heat on things, And by the scorched scars exhaling round The heavy fumes of sulphur. For all these Are marks, O not of wind or rain, but fire.
Again, they often enkindle even the roofs Of houses and inside the very rooms With swift flame hold a fierce dominion.
Know thou that nature fashioned this fire Subtler than fires all other, with minute And dartling bodies,- a fire 'gainst which there's naught Can in the least hold out: the thunderbolt, The mighty, passes through the hedging walls Of houses, like to voices or a shout,-Through stones, through bronze it passes, and it melts Upon the instant bronze and gold; and makes, Likewise, the wines sudden to vanish forth, The wine-jars intact,- because, ye see, Its heat arriving renders loose and porous Readily all the wine- jar's earthen sides, And winding its way within, it scattereth The elements primordial of the wine With speedy dissolution- process which Even in an age the fiery steam of sun Could not accomplish, however puissant he With his hot coruscations: so much more Agile and overpowering is this force.
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Now in what manner engendered are these things, How fashioned of such impetuous strength As to cleave towers asunder, and houses all To overtopple, and to wrench apart Timbers and beams, and heroes' monuments To pile in ruins and upheave amain, And to take breath forever out of men, And to o'erthrow the cattle everywhere,-Yes, by what force the lightnings do all this, All this and more, I will unfold to thee, Nor longer keep thee in mere promises.
The bolts of thunder, then, must be conceived As all begotten in those crasser clouds Up-piled aloft; for, from the sky serene And from the clouds of lighter density, None are sent forth forever. That 'tis so Beyond a doubt, fact plain to sense declares:
To wit, at such a time the densed clouds So mass themselves through all the upper air That we might think that round about all murk Had parted forth from Acheron and filled The mighty vaults of sky- so grievously, As gathers thus the storm-clouds' gruesome might, Do faces of black horror hang on high-When tempest begins its thunderbolts to forge.
Besides, full often also out at sea A blackest thunderhead, like cataract Of pitch hurled down from heaven, and far away Bulging with murkiness, down on the waves Falls with vast uproar, and draws on amain The darkling tempests big with thunderbolts And hurricanes, itself the while so crammed Tremendously with fires and winds, that even Back on the lands the people shudder round And seek for cover. Therefore, as I said, The storm must be conceived as o'er our head Towering most high; for never would the clouds O'erwhelm the lands with such a massy dark, Unless up-builded heap on lofty heap, To shut the round sun off. Nor could the clouds, As on they come, engulf with rain so vast As thus to make the rivers overflow And fields to float, if ether were not thus Furnished with lofty-piled clouds. Lo, then, Here be all things fulfilled with winds and fires-Hence the long lightnings and the thunders loud.
For, verily, I've taught thee even now How cavernous clouds hold seeds innumerable Of fiery exhalations, and they must From off the sunbeams and the heat of these Take many still. And so, when that same wind (Which, haply, into one region of the sky Collects those clouds) hath pressed from out the same The many fiery seeds, and with that fire Hath at the same time inter-mixed itself, O then and there that wind, a whirlwind now, Deep in the belly of the cloud spins round In narrow confines, and sharpens there inside In glowing furnaces the thunderbolt.