VOLCANIC ACTION, HAWAII. 22] 
longer than the other. We may therefore comprehend that the two 
legs of the syphon may differ as much in length as at Mount Loa, and 
the lavas, owing to unequal inflation, still balance one another. 
IV. Volcanoes fed by the fresh waters of the Island.—If, then, the 
conduits are separately operated on, as must be admitted, whatever be 
our conclusions with regard to their union or disconnexion below, we 
see additional reason for attributing a large part, if not the whole of 
the action of water to points near the surface, and we may also say, to 
the fresh waters of the land. The difference of action in the pools of 
Kilauea, can have no other cause, as far as we can understand; and 
the explanation of the relative phases of Kilauea and Mokua-weo-weo 
requires none other. Salt water may have some influence. But 
when we consider the facts, that borings, directly on a sea-shore, even 
one comparatively flat, will always bring fresh water ; and on a coral 
island, ten feet is sufficient depth for pure water a hundred yards 
from the beach, we must admit that only deep in the sea will the 
ocean’s pressure force its waters into the volcanic mountain—a depth 
greater, it is believed, than is consistent with the facts above explained. 
The rains that fall over the island, and the waters from the melting 
snows, are, to a very great extent, absorbed by the cavernous rocks, 
and they must make their way down to the fires. If we keep in view 
the area of Mount Loa (at least 3000 square miles), and also its height, 
and consider the great amount of water that flows ordinarily in num- 
berless streams from the surface of such a mountain, we may conceive 
of the extent of the contribution received by the fires below. 
V. Volcanoes no Safety- Valves.—F rom these considerations we may 
doubt whether volcanoes are ever “ safety-valves,” as they have been 
often called, and are almost universally considered by writers on these 
subjects. We may strongly doubt whether action so deep-seated as 
that of the earthquake must be, can often find relief in the narrow chan- 
nels of a volcano, miles in length. ‘The conduit of Mokua-weo-weo is 
almost three miles long, down to the level of the sea. Assuredly if 
while Kilauea is open on the flanks of Mount Loa,—a vast gulf three 
and a quarter miles in diameter,—lavas still rise and are poured out at 
an elevation more than 10,000 feet above it, Kilauea is no safety-valve, 
even to the area covered by the single mountain alone. If lavas may 
be ejected from the very lip of Kilauea 1000 feet above its bottom, 
while the pools are still boiling below, Kilauea, notwithstanding its 
extent, the size of its great lakes of lava, and the freedom of the inces- 
sant ebullition, is not a safety-valve that can protect even its own im- 
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