Underground Rivers - University of New Mexico

Chapter 9 -- Thermodynamic Engines
Mt. Vesuvius
Stromboli
Mt. Etna
To speculators steeped in classical history, the earth's igneous power seemed more than
sufficient to pump hillside fountains. Da Vinci argued initially that water is drawn upwards through
subterranean passages by the heat of the sun, but the heat source did not please da Vinci for two
reasons.
As mountain crests are closer to the sun, flowing water shouldn’t be frigid.
The solar engine should work best in the summer when water is warmer, but the summer is
often when springs diminish.
Aware of the 1494 Mt. Etna eruption and the 1500 event of Mt. Vesuvius, da Vinci turned toward
an interior fire as a better explanation of spring water.
Now the same heat which holds up so great a weight of water as is seen to rain from the
clouds, draws them from below upwards, from the foot of the mountains, and leads and holds
them within the summits of the mountains, and these finding some fissures, issue continuously
and cause rivers.
And this water, which passes through a closed conduit inside the body of the mountain like a
dead thing, cannot come forth from its low place unless it is warmed by the vital heat of the
spring time. Again, the heat of the element of fire and, by day, the heat of the sun, have power
to draw forth the moisture of the low parts of the mountains and to draw them up, in the same
way as it draws the clouds and collects their moisture from the bed of the sea.
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