The following details relative to the volcanic springs of boiling mud in
Java are extracted from the Penang Gazette.
Having received an account of a wonderful phenomenon in the plains of
Grobogna, a party set off, from Solo, in September, 1814, to examine it.
On approaching the place, they saw what at first appeared like the surf
breaking over the rocks, with a heavy spray falling to the leeward.
Alighting, they went to the “Bluddugs,” as the Javanese call them, which
they found to be an elevated plain of mud, about two miles in
circumference, in the center of which immense bodies of soft mud were
thrown up to the hight of ten or fifteen feet, in the form of large
bubbles, which bursting, emitted great volumes of dense white smoke. The
largest bubbles, of which there were two, rose and burst some seven or
eight times a minute, throwing up from one to three tuns of mud, the
smell of the smoke from which was very offensive, like the washings of a
gun-barrel. It was both difficult and dangerous to go near the large
bubbles, as the surface, except where it had been hardened by the sun,
was all a quagmire. They went, however, close to a small bubble, (the
plain was full of them, of all sizes,) and observed it for some time. It
appeared to heave and swell, and when the air within had raised it to
some hight, it burst, and the mud fell down in concentric circles, and
then remained quiet till again it was raised, again to burst; which was
at intervals of from one to two minutes. The water drained from the mud
was collected by the Javanese, and being exposed to the sun deposited
crystals of salt.
Next morning the party rode to a place in the forest, to view a salt
lake, a mud hillock, and various boiling pools. The lake was about half
a mile in circumference, of dirty-looking water, boiling up all over in
gurgling eddies; the water being cold, bitter and salt, with an
offensive smell. The mud hillock, which was near, was about fifteen feet
high, in the form of a cone, with a base of eighty, and a top of eight
feet diameter. The top was open, and the interior, which was full of
boiling and heaving mud, was found to be eleven fathoms deep. Every rise
of the mud was attended by a rumbling noise from within; and the mud was
more liquid than at the bluddugs, and unattended by smoke. Near the foot
of this hillock was a small pool of water, like that of the lake,
boiling violently; and some two hundred yards distant, two larger pools
or springs of the same general description, the smell of which was very
offensive, and the boiling of which could be heard at quite a distance,
resembling the noise of a small waterfall. The water both of the
bluddugs and of the lake, is used medicinally by the Javanese, and also,
as stated above, for the making of salt, which is gathered in
considerable quantities, and the government income from which adds not a
little to the public revenues. The general cause of the phenomena here
witnessed, is supposed, beyond all question, to be volcanic; the salt
water being thrown up by this agency in a heated state, and thus
mingling with the soil to produce the boiling and heaving mud above
described.