Underground Rivers - University of New Mexico

Chapter 12 -- Superterranean Metrics
Below is Halley's hydrologic model showing the caverns-springs-rivers route.
Clouds
Ocean
Caverns
We will return to Halley's condensation hypothesis as it relates to caves in Chapter 39, but before
then, we’ll meet the astronomer looking further downwards in Chapter 14, Hollow Earth
Geophysics.
Charles Hutton (1737-1823) was an encyclopedist, striving to sort the
burgeoning set of scientific findings into an objective framework.
Following are several entries from his A Mathematical and Philosophical
Dictionary, Containing an Explanation of the Terms, and an Account of
the Several Subjects (1795).
As to what would become to be today’s common understanding of the
hydrologic cycle,
The most general and probable opinion among philosophers, on the formation of Springs, is,
that they are owing to rain. The rain-water penetrates the earth till such time as it meets a
clayey soil, or stratum; which proving a bottom sufficiently solid to sustain and stop its descent,
it glides along it that way to which the earth declines, till, meeting with a place or aperture on
the surface, through which it may escape, it forms a Spring, and perhaps the head of a stream
or brook.
Regarding Perrault’s 6:1 rainfall/runoff ratio,
Precipitation
Rivers
Springs
Now, that the rain is sufficient for this effect, appears from hence, that upon calculating the
quantity of rain and snow which falls yearly on the tract of ground that is to furnish, for instance,
the water of the Seine, it is found that this river does not take up above one sixth part of it.
Hutton understood enough basic hydraulics to envision the upper slopes of a nearby mountain
feeding a geologic stratum that curves below nearby valleys to rise elsewhere.
And if we sometimes see Springs on high grounds, and even on the tops of mountains, they
must come from other remoter places, considerably higher, along beds of clay, or clayey
ground, as in their natural channels. So that if there happen to be a valley between a mountain
on whose top is a Spring, and the mountain which is to furnish it with water, the Spring must be
considered as water conducted from a reservoir of a certain height, through a subterraneous
channel, to make a jet of an almost equal height.
Hutton, however, perpetuated Halley's subterranean cavern theory.
The tops of mountains usually abound with cavities and subterraneous caverns, formed by
nature to serve as reservoirs; and their pointed summits, which seem to pierce the clouds, stop
those vapors which float in the atmosphere; which being thus condensed, they precipitate in
water, and by their gravity and fluidity easily penetrate through beds of sand and the lighter
earth, till they become stopped in their descent by the denser strata, such as beds of clay,
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