Geological researches in China, Mongolia, and Japan, during the years 1862-1865.

CHINA, MONGOLIA, AND JAPAN. 87
While we were here drops of scalding mud were incessantly thrown out, but
regular mud flows appear to be very rare.
The superintendent of the sulphur works informed me that when new vents
open, mud and large blocks of rock are thrown out with much violence. Such
blocks cover the interior of the crater, and have been already mentioned; they are
frequently almost entirely decomposed by the action of the gases.
From an extinct vent I traced a stream of mud, following the bed of a gully,
for several hundred yards. It is hard, compact, and filled with small crystalline
needles of sulphur, the longer direction of which was found to be invariably at
right angles to the nearest surface, by which either the heat or moisture, or both,
escaped. These crystals occur equally distributed throughout the mass the whole
length of the stream, and produce, on a small scale, a tendency to columnar structure. They cannot, considering their position, have been crystallized until the
mud was quiescent and hardening, and as the solidification depended on the escape
of the moisture that rendered it fluid, it forms, I think, a good illustration of the
fact that columnar structure is not necessarily a result of cooling, but rather of the
escape of the "vehicle of fluidity," whether this be heat or water, or, as here, both
combined.
The stream in question appears to be the result of a single flow filling the
inequalities in the bottom of the gully, and is in places several feet deep.
The government has large sulphur works on this mountain, with which the production of alum was formerly combined. The material used, from which the sulphur is extracted, is the debris formed by the ever-falling walls of the crater, and
which is said to contain from 25 to 50, and even 60, per cent. of the mineral, in
layers and impregnated through the mass.
Without further preparation than being broken with the hammer, this raw
material is put into three iron pots over a fire. Each of these vessels is composed
of two parts, a cylinder and a hemispherical bottom or pot on which it stands, the
whole being about two and a half feet deep and two feet in diameter. After melting, the impurities seem to settle to the bottom, and the top is ladled out into shalFig. 12
U Ub U U U
a Pots. b Fireplaces. c Shallow depressions.
low depressions in the ground. When this is cooled, it is a hardened mud filled
with crystals of sulphur in needles, their longer axes at a right angle to the surface
of the cooled mass, and the whole product differs from the mud described above, as