This section is from the book "A Library Of Wonders And Curiosities Found In Nature And Art, Science And Literature", by I. Platt. Also available from Amazon: A library of wonders and curiosities.
We shall incorporate in this chapter, the following interesting account of Volcanic Eruptions of Mud and Salt, in the Island of Java; by T. S. Goad, Esq. of the Honourable Company's Bengal Civil Service.
"Having received (says the writer) an extraordinary account of a natural phenomenon in the plains of Grobogan, fifty pals (or miles) north-east of Solo, a party, of which I was one, set off from Solo on the eighth of September, 1815, to examine it.
"On approaching the village of Kuhoo, we saw, between two trees in a plain, an appearance like the surf breaking over rocks, with a strong spray falling to leeward. The spot was completely surrounded by huts, for the manufacture of salt, and at a distance looked like a large village. Alighting, we went to the Bludugs, as the Javanese call them. They are situated in the village of Kuhoo, and by Europeans are called by that name. We found them to be on an elevated plain of mud, about two miles in circumference, in the centre of which immense bodies of salt mud were thrown up, to the height of from ten to fifteen feet, in the form of large globes, which, bursting, emitted volumes of dense white smoke. These large globes or bubbles, of which there were two, continued throwing up, and bursting seven or eight times in a minute At times they throw up two or three tons of mud. We got to leeward of the smoke, and found it to smell like the wash ing of a gun-barrel.
"As the globes burst, they threw the mud out from the centre with a pretty loud noise, occasioned by the falling of the mud upon that which surrounded it, and of which the plain is composed. It was difficult and dangerous to approach the large globes or bubbles, as the ground was all a quagmire, except where the surface of the mud had become hardened by the sun; upon this we approached cautiously to within fifty yards of the largest bubble, or mud pudding, as it might very properly be called, for it was of the consistency of a custard-pudding, and of very considerable diameter: here and there, where the foot accidentally rested on a spot not sufficiently hardened, it sunk, to the no small distress of the walker.
"We also got close to a small globe or bubble, (the plain being full of them of different sizes,) and observed it closely for some time. It appeared to heave and swell, and when the internal air had raised it to some height, it burst, and fell down in concentric circles, in which shape it remained quiet until a sufficient quantity of air was again formed internally, to raise and burst another bubble. This continued at intervals from about one-half to two minutes. From various other parts of the quagmire round the large globes or bubbles, there were occasionally small quantities of mud shot up like rockets to the height of twenty or thirty feet, and accompanied by smoke. This was in parts where the mud was of too stiff a consistency to rise in globes or bubbles. The mud at all the places we came near was cold on the surface, but we were told it was warm beneath. The water which drains from the mud is collected by the Javanese, and by being exposed in the hollows of split bamboos to the rays of the sun, deposits crystals of salt. The salt thus made is reserved exclusively for the Emperor of Solo. In dry weather it yields thirty dudjins, of one hundred catties each, every month; but in wet or cloudy weather, less.
"In the afternoon we rode to a place in a forest, called Ram sam, to view a salt lake, a mud hillock, and various boiling, or rather bubbling, pools. The lake was about half a mile in circumference, of a dirty looking water, boiling up all over in gurgling bodies, but more particularly in the centre, which appeared like a strong spring; the water was quite cold, and tasted bitter, salt, and sour, and had an offensive smell. About thirty yards from the lake stood the mud hillock, which was about fifteen feet high from the level of the earth. The diameter of its base was about twenty-five yards, its top about eight feet, and in form an exact cone. The top is open, and the interior keeps constantly working, and heaving up mud in globular forms, like the Bludugs. The hillock is entirely formed of mud which has flowed out of the top; every rise of the mud was accompanied by a rumbling noise from the bottom of the hillock, which was distinctly heard for some seconds before the bubbles burst. The outside of the hillock was quite firm. We stood on the edge of the opening and sounded it, and found it to be eleven fathoms deep. The mud was more liquid than at the Bludugs, and no smoke was emitted from the lake, hillock, or pools.
"Close to the foot of the hillock was a small pool of the same water as the lake, which appeared exactly like a pot of water boiling violently; it was shallow, except in the centre, into which we thrust a stick twelve feet long, but found no bottom. The hole not being perpendicular, we could not sound it with a line.
"About 200 yards from the lake, were several large pools or springs, two of which were eight or ten feet in diameter. They were like the small pool, but boiled more violently, and smelt excessively. The ground around them was hot to the feet, and the air which issued from them quite hot, so that it was most probably inflammable; but we did not ascertain this. We heard the boiling at the distance of thirty yards from the pools, resembling in noise a waterfall. The pools did not overflow; of course the bubbling was occasioned by the rising of air alone. The water of one of the pools appeared to contain a mixture of earth and lime, and, from the taste, to be combined with alkali. The water of the Bludugs and the lake is used medicinally by the Javanese, and cattle drinking of the water are poisoned.