In January 1417, Gian Francesco Poggio Bracciolini (1380–1459) - an Italian humanist, historian, scholar in the Papal Court and book-hunter - discovered in a monastery library in the southern Germany (probably the Benedictine abbey in Fulda) a manuscript that was missing for 1000 years, the only surviving copy of Lucretius's De Rerum Natura ("On the Nature of Things").
De Rerum Natura was a Latin poem of 7400 lines, divided into six books, in which the Roman poet and philosopher Lucretius (c. 99 BC–c. 55 BC) describes the Epicureanism, a system of philosophy based on the teachings of the Greek philosopher Epicurus (341–270 BC). In the poem, Lucretius argue, amongst other things, that the Universe functioned without the aid of gods, that the Earth is the center of the Universe and that the fundamental constituents of the world were very small invisible particles (atoms) in eternal motion colliding and swerving with no purpose or plan behind their motions. Lucretius devoted the Book 6 of the De Rerum Natura to meteorology. Of particular interest for one of my projects (on the evolution of the theories on tornado formation in Europe) where the lines 422–451:
“For the rest is easy now to understand
How what the Greeks named ‘presteres’* from above
Are sent down on the sea. Sometimes you know
A pillar, so to speak, is let right down
From sky to sea, round which the surges boil
Lashed by the blowing winds, and ships that are
Caught in that turmoil come in greatest risk.
And this takes place sometimes when the wind’s force
Can t burst the cloud it aimed at, but can urge
It downwards, like a pillar that is set
’Tween sea and sky, coming by slow degrees,
Pushed and extended as t were from above
Over the waves by strength of arm and hand :
And when the cloud is rent, the force of wind
Bursts forth upon the sea, and raises up
A wondrous surging in the waves around:
The eddy whirling round descends and brings
Yon cloud of pliant body down with it :
And having thrust it, heavy as it is,
Down to the level of the sea, the eddy then
Plunges itself entire into the waves,
And stirs the ocean with terrific noise,
And makes it boil. It chances too sometimes
That the eddying wind wraps up itself in clouds,
And gathering from the air the seeds of clouds,
As though let down from heaven, imitates
The prester. And when it has reached the earth
And burst, it vomits forth a whirling storm
Of vast dimensions, but as it is rare,
And mountains must obstruct its way on land,
More frequent it is seen in the wide expanse
Of ocean and beneath the spreading sky.”
The title page Lambin's 1563 edition of De Rerum Natura (source)
Thus, Lucretius describes two mechanisms for the formation of waterspouts and whirlwinds. In the first one, similar with mechanism described by Aristotle for the formation of whirlwinds, the wind cannot break the cloud, and it is forced down in the shape of a pillar to the sea where it bursts and causes a furious boiling and surging. In the second mechanism, the whirlwind form outside the cloud by gathering "the seed of clouds" (or atoms of cloud) and wrap them round to imitate a real prester that is observed sometimes over land, but often on the sea. Through the Middle Ages till the end of the 17th Century, authors generally repeated Lucretius's theories to explain the formation of tornadoes and waterspouts.
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(*) In Greek in the original text (i.e., πρηστήρες) meaning a meteor or exhalation formerly supposed to be thrown from the clouds with such violence that by collision it is set on fire. (source)