954 J.D. Dana on the recent Eruption of Mauna Loa. 
Art. XXX.—WNote on the Eruption of Mauna Loa; by 
} James D. Dana.* ) 
Tue account of Mauna Loa, by Rev. Titus Coan,} together 
with the additional information from letters appended to this pa- 
per, suggests a few thoughts confirmatory of views mentioned in 
another place by the writer. 
I. The eruption described, although so vast in its extent, com- 
menced with no earthquake—no internal thunderings—no pre- 
monitions whatever that were perceptible at the base of the moun- 
tain. In almost all descriptions of volcanoes, these phenomena 
_are set down as essential to the result, especially if the eruption 
be of much extent. Some force is supposed, in one way or an- 
other, to get beneath the column of lava, and by sudden action to 
eject the lavas with violence, amid terrific exhibitions of volcanic 
power. But in the majestic dome of Mauna Loa, where the lavas 
are carried to a height of 14,000 feet, the outbreak is quiet and 
noiseless; the mountain opens, the lavas flow. The vivid de- 
scription of Mr. Coan, marked as it is with the actual terrors of 
the scene, strikingly sustains these statements.. For how unlike 
Vesuvius in her great outbreaks is the Hawaian volcano, when 
the crater, in its intensest eruption, could be approached “ within 
forty or fifty yards on the windward side,” or “ within two miles 
on the leeward,” and the traveller need retire but to the dis- 
tence of “a mile” from the very scene of eruption for his “ night 
vigils.” 
Il. The mobility of the Hawaian lavas is most remarkably ex- 
emplified in this eruption. The fiery rock at the crater formed 
literally an open boiling fountain, instead of appearing in erupuvé 
discharges through a narrow-necked funnel. A jet of clear liquid 
lava shot up in ceaseless flow to a height of 300 feet or more, 
and, with its surrounding jets and falling spray, produced, as Mr. 
Fuller says, the effect of a Gothic structure of molten metal, with 
its shafts and pinnacles and buttresses, in quick incessant change 
—now rising into a tall spire 700 feet in height, now spreading 
into more massy forms, and ever dazzling the sight with} 
brilliancy. The scene of this display, according to Mr. Coad, 
was 5,000 feet below the summit outbreak,t and it would actually 
appear, as he implies, that the hydrostatic pressure of the Socpy 
column of lavas in the mountain was the power that kept the jet 
action. Such a fountain of molten rock is majestic beyond con” 
ception ; and the more wonderful, the more majestic, viewed as 
the effect of simple pressure, with none of the convulsive heavings 
* See farther the author's ters III and VII; als 
this Journal, [2], ix, 347, and Py at - Report The volume, p. 212) 
} Seven thousand feet, or half way to the base, according to Mr. Fuller. 
