Underground Rivers - University of New Mexico

Chapter 10 -- Geophysical, Pnuematic and Electromagnetic Engines
We can look to Thales (Chapter 2) for associations between earthquakes and springflow, but we'll
again pick up the subject in the late 1400s. Da Vinci’s evidence included,
That there are springs which suddenly break forth in earthquakes or other convulsions and
suddenly fail; and this happened in a mountain in Savoy where certain forests sank in and left a
very deep gap, and about four miles from here the earth opened itself like a gulf in the
mountain, and threw out a sudden and immense flood of water which scoured the whole of a
little valley of the tilled soil, vineyards and houses, and did the greatest mischief, wherever it
overflowed.
Unlike many of da Vinci’s hydrologic claims, he would have had personal knowledge of the Alpine
Savoy. No subterranean reservoir, there or anywhere, has ever been rent open by an
earthquake, however. Were such reservoirs to exist and were tremors to rupture them, we'd still
be pressed to explain springs that don't diminish over the long period.
Pneumatics
The atmosphere was also thought to motivate underground rivers, the role variously taken to
come from the suction of wind, a vacuum produced by the outflow of springs, pressure on the
land surface and/or pressure from enclosed cavities.
Da Vinci considered Heron of
Alexandria’s experiment in
which a burning coal is placed
in an inverted vessel inserted
below a water surface. Water
rises within the vessel.
Springs
Ocean
Da Vinci correctly attributed the phenomenon to the rarification of air within the receptacle -- as
opposed to the direct action of the heat -- and was thus willing to reject the hypothesis in which
the heat of the sun draws the water to the heights of mountains.
And if you should say as has been said that the sun sucks up and draws the waters from the
roots of the mountains to their summits, then as the heat draws the moisture to itself the heat
which is more powerful would draw to itself a greater amount of water than the less powerful.
In summer therefore during the fiery heats the springs of the waters would have to rise higher
into the summits of the mountains than they do in winter; but we see it is the contrary seeing
that in summer the rivers lack a great part of their waters.
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