water or fissure be transverse to the line of transit of the earth-wave,
the effect of the arrival of the earth-wave at the watery fissure will
be, at the instant, to compress its walls more or less together, and so
squeeze out the water, which will, for a moment, gush up at the
spring-head like a fountain, and again remain in repose after the
transit of the wave."

_Gradual closing in of fissures._--Sir W. Hamilton was shown several
deep fissures in the vicinity of Mileto, which, although not one of
them was above a foot in breadth, had opened so wide during the
earthquake as to swallow an ox and nearly one hundred goats. The
Academicians also found, on their return through districts which they
had passed at the commencement of their tour, that many rents had, in
that short interval, gradually closed in, so that their width had
diminished several feet, and the opposite walls had sometimes nearly
met. It is natural that this should happen in argillaceous strata,
while, in more solid rocks, we may expect that fissures will remain open
for ages. Should this be ascertained to be a general fact in countries
convulsed by earthquakes, it may afford a satisfactory explanation of a
common phenomenon in mineral veins. Such veins often retain their full
size so long as the rocks consist of limestone, granite, or other
indurated materials; but they contract their dimensions, become mere
threads, or are even entirely cut off, where masses of an argillaceous
nature are interposed. If we suppose the filling up of fissures with
metallic and other ingredients to be a process requiring ages for its
completion, it is obvious that the opposite walls of rents, where strata
consist of yielding materials, must collapse or approach very near to
each other before sufficient time is allowed for the accretion of a
large quantity of veinstone.

_Thermal waters augmented._--It is stated by Grimaldi, that the thermal
waters of St. Eufemia, in Terra di Amato, which first burst out during
the earthquake of 1638, acquired, in February, 1783, an augmentation
both in quantity and degree of heat. This fact appears to indicate a
connection between the heat of the interior and the fissures caused by
the Calabrian earthquakes, notwithstanding the absence of volcanic
rocks, either ancient or modern, in that district.

_Bounding of detached masses into the air._--The violence of the
movement of the ground upwards was singularly illustrated by what the
Acad