Underground Rivers - University of New Mexico

Chapter 10 -- Geophysical, Pnuematic and Electromagnetic Engines
Causes of Blowing Springs and Wells.
The two classes of blowing springs and wells above described appear to be due to two entirely
different causes. Those of the first class, of which the Grant Blowing Spring is a good type,
seem to be due entirely to the difference of atmospheric pressure of the air on the outside and
on the inside of the cave.
It's the pneumatic subterranean engine, the earth's interior air pressure blowing out the water.
In the second class of wells and springs, the constantly outgoing or the constantly ingoing
current is entirely independent of atmospheric conditions. The currents, whether outward or
inward, act with equal energy during high or low barometer and always move in the same
direction. The Boston and the Lester deep wells are excellent examples of wells and springs of
this class. The phenomenon which they exhibit seems to be due entirely to the friction of the
air on a rapidly moving current of water. This phenomenon is beautifully illustrated in Richard's
water air-blast, to be found in many well-equipped chemical laboratories. In the Boston well,
and also in the Lester well, appear almost exactly the same conditions met with in Richard's
water air blast. The well itself forms the inlet for the air, and the rapidly flowing stream in the
subterranean channel below completes the conditions necessary for an ingoing air blast... It
naturally follows that it must escape at some other point as an outgoing current, thus giving rise
to continuously blowing caves or springs. As underground streams frequently pass from one
bed of rock to another in their subterranean course, they, no doubt, often form waterfalls which
possess all the essential conditions necessary for producing an air blast, thus giving rise to
continuously blowing caves and springs.
The two classes of blowing wells and springs
Low
Pressure
High Air Flow
Pressure
McCallie provided additional explanation in A Preliminary Report on the Underground Waters of
Georgia (1908).
It will be seen by the description of the Quitman deep well that not all deep wells penetrating
subterranean channels with swift flowing streams are blowing or sucking wells. This may be
accounted for by the channel being only partially filled with water, and the air being able to
circulate freely within. The essential condition of continuous suction in wells is that the air once
dragged into the underground stream by the friction of the water cannot again reach the point of
intake.
The current of air above noted at the entrance of the cavers at Forest Falls is also due to the
friction of the air and water, but as the air is free to escape into a subterranean chamber and
the accompanying air could not escape by the way of its entrance it would give rise to a strong
blast. As underground streams frequently pass from one bed of rock to another in their
subterranean course, they no doubt often form waterfalls which possess all of the essential
conditions necessary for producing air an blast and thus give rise to continuously flowing caves
or springs,
McCallie's pneumatic theory wasn't confined to scientific publication, as evidenced in the Bend
[Oregon] Bulletin, March 30, 1906
Drafts over deep wells are usually due to changes of temperature or barometric pressure, air
being forced in as the pressure rises and drawn out when the barometer is falling. But in tow
wells in the Vicksburg Jackson limestone of southern Georgia have shown the strange
phenomenon of a continuous in-draft. This has been investigated by S.W. McCallie, who has
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