"It is estimated, that an extent of ground, of the mountain itself and its immediate environs, fifteen miles long and full six broad, was by this commotion swallowed up in the bowels of the earth. Several persons, sent to examine the condition of the neighbourhood, made report, that they found it impossible to approach the mountain, on account of the heat of the substances which covered its circumference, and which were piled on each other to the height of three feet; although this was the 24th of September, and thus full six weeks after the catastrophe. It is also mentioned, that forty villages, partly swallowed up by the ground and partly covered by the substances thrown out, were destroyed on this occasion, and that 2,957 of the inhabitants perished. A proportionate number of cattle was also destroyed, and most of the plantations of cotton, indigo, and coffee, in the adjacent districts, were buried under the volcanic matter. The effects of this explosion are still very apparent on the remains of this volcano; but I defer an account of it, till I have had an opportunity of making a more minute examination.
"Guntur.—The whole of the eastern part of this mountain is completely naked, and exposes to view, in a striking manner, the course of the lavas of the latter eruptions: the top is a regular cone, and covered with loose fragments of lava. I shall give a very concise abstract of the observations on the mountain, and on the different streams of lava which have lately flowed from its crater. I could distinctly trace, from the base of the conical top to the roots of the mountain, five different eruptions. The latest stream of lava which I examined (the mountain has since had a later eruption) was thrown out in 1800. Its course along the top cannot be distinctly observed, being completely covered with sand and small fragments of lava, which generally rise towards the end of an eruption. At the place where the stream first appeared distinctly, it was about five yards broad and completely even on the surface: having proceeded about twenty yards further it gradually widened, and was formed into a connected stream, higher in the middle, the sides tapering or inclining towards the top, forming a ridge with a pointed or sharp back. As the stream arrived at the foot of the mountain, it spread more and more, and pursued its course to the eastward, about six hundred yards over the adjacent country. Its greatest breadth, from north to south, is about one hundred and sixty yards, and it terminates abruptly by a rounded margin, consisting of large blocks of lava piled upon each other, nearly perpendicularly, to the height of fifteen to twenty feet.
"This stream of lava, like all the others of later date which I have examined on the island, does not consist of a connected mass of fluid lava, united like a stream of melted metal; at least on the surface where it is exposed to view. It is made up of separate masses, which have an irregular (generally oblong or cubical) shape, and lie upon each other as 'loose disjointed clods,' in an immense variety of disposition. In some of these fragments I think I could observe a tendency to assume the regular basaltic figure. During its course down the steeps of the mountain, the stream, as has been observed, forms the long connected ridge (which has been described above, in the account of the volcanos, as generally covering the sides); but having arrived at the foot and spread more at large, these lumps of lava dispose themselves, in some instances, in plains, bounded by deep vallies: now they rise to a considerable height, and form a steep perpendicular eminence; then again they are piled upon each other more gradually, and appear rising by steps and divisions. But to give an accurate description of the arrangement of these fragments of lava would be unnecessarily prolix, and would require, to be clearly understood, a good drawing. In different places, the sulphureous vapours have forced their way through the interstices of the blocks of lava. The sides of their outlets (whose form is very irregular) is covered with a white calcareous crust; and the heat is so great, that small pieces of paper thrown into them are immediately singed.
"This stream of lava is bounded on the north by another, of the same nature and disposition, thrown out of the mountain (according to an estimate made from the commencement and progress of vegetation upon it) about thirty years ago. In its course along the sides of the mountain it forms the same pointed ridges above described. It affords a plain demonstration of the manner in which the surface of lava is decomposed and rendered fit for vegetation. A third district of lava bounds the new stream first described in the south: it is more extensive than the others, and consists of several distinct regions, probably thrown out during one eruption (which appears to have been more violent than the others), but in successive periods shortly following each other. It extends farther to the eastward than the others, and covers a great portion of the foot of the mountain. Vegetation has already made considerable progress upon it: in the vallies between the separate streams of lava are found not only plants but also small shrubs. At one place, near the termination of this stream, the lava is piled up in two irregular ridges to the height of twenty feet; and at a small distance from its eastern extremity, in a spot which has escaped the effects of the later eruptions, and is covered by pleasant wood, are three different hot wells, within the circumference of a quarter of a mile. In the south, this district of lava is bounded by a recent stream, which appears to have been thrown out in 1800, by the same eruption which produced the first mentioned stream. It differs from the others only in the colour of its lava, which has a reddish hue: it is less considerable in extent than any of the others, and cannot be traced far from the foot of the mountain. The fifth stream of lava which I examined is still farther towards the south, and is one of the oldest which have been discharged from the eastern part of the crater. Near the foot of the mountain, vegetation has made greater progress than in any of the other districts of lava.
"The colour of the recent lava of this mountain is jet-black or grey: one of the streams only has a reddish colour. Its texture is very loose, and its fracture very porous. The smaller fragments have much the appearance of the scoriæ of a blacksmith's forge: on being thrown against each other, they emit a sound like two bricks coming into contact. The interior crater of this mountain, as it has remained after the eruption of 1800, is less interesting than the others which I have examined. Its shape is somewhat oval, the greatest diameter being about one hundred yards: its depth is not very considerable. Its structure, in general, is similar to that of Tankuban-prahu. It has one remaining aperture, which discharges with great force hot sulphureous vapours."
Batavian Transactions, vol. ix.
[24] Mineral wells, of various qualities, are found in almost every part of the island. As an instance of the hot wells, the following account of those found in Cheribon is selected. "At the village of Bongas (situated about ten miles to the north-east of Karang-Sambong) I directed my route to the large mountain, in order to examine part of the hills along its foot, called the hills of Pana-wangan, and several hot wells which are found near their borders. On approaching these hills, after a very gentle acclivity covered entirely by calcareous stones, I very soon came to the spot of the hot wells. They are found on a gently inclining plain, about one hundred yards in circumference. This plain is perfectly white; and on approaching it, it is perceived at some distance by a sulphureous vapour, arising from the whole neighbourhood. The water springs from several apertures, but their temperatures are not equal; the hottest indicates the degree of one hundred and thirty of Fahrenheit's scale. They all contain a very large quantity of calcareous earth in solution and suspension, which coming into contact with the air, immediately separates, and adheres to the surrounding objects, or is precipitated to the ground. The branches of the shrubs in the vicinity are all enveloped by a stalactical incrustation. The water from the different wells gently descending the white calcareous plain, is collected in a rivulet below. A large number of calcareous rocks are found in the vicinity of the plains; some are covered with elegant crystals of calcareous spar, others have a coralline appearance, and some have the fracture of alabaster. On proceeding up the hills, immense irregular blocks of calcareous rocks are found strewed about in the valleys. About one hundred yards above this district are several wells of naphtha, or petroleum. It rises in small plashes of water, about twelve or eighteen inches in diameter, upon which it drives its black specks, emitting the peculiar odour of the petroleum. The earth in the circumference of these plashes is strongly impregnated with this oil: it is very tough, and from that immediately bounding apertures, the naphtha flows out on its being pressed; some portions exactly resemble asphaltum. A considerable space of ground is occupied by these wells. The stones are all calcareous. A few hundred yards above this spot, the borders of the hills become very steep. I examined them to some extent. They are composed exclusively of calcareous stones. Several extensive stalactitic caves are found at no great distance above the wells; they exhibit the usual appearances of calcareous caves and vaults. The process of incrustation is continually going on. In some places, deep perforations extend into the heart of the hills."—Essay on the Mineralogy of Java, by Dr. Horsfield. Bat. Trans. vol. ix.
Among other objects of curiosity, which can only be illustrated by particular description, are the explosions of mud, situated between the district of Grobogan on the west, and of Blora and Jipang on the east. By the natives they are termed Blédeg, and are described by Dr. Horsfield as salt wells.
"These salt wells," he observes, "are dispersed through a district of country several miles in circumference, the base of which, like that of other parts of the island which furnish mineral and other saline waters, is limestone. They are of considerable number, and force themselves upwards, through apertures in the rocks, with some violence and ebullition. The waters are strongly impregnated with sea-salt, and yield upon evaporation very good salt for culinary purposes. (In quantity not less than two hundred tons in the year.)
"About the centre of this limestone district, is found an extraordinary volcanic phenomenon. On approaching it from a distance, it is first discovered by a large volume of smoke rising and disappearing at intervals of a few seconds, resembling the vapours arising from a violent surf: a dull noise is heard, like that of distant thunder. Having advanced so near, that the vision was no longer impeded by the smoke, a large hemispherical mass was observed, consisting of black earth, mixed with water, about sixteen feet in diameter, rising to the height of twenty or thirty feet in a perfectly regular manner, and as it were pushed up, by a force beneath; which suddenly exploded with a dull noise, and scattered about a volume of black mud in every direction. After an interval of two or three, or sometimes four or five seconds, the hemispherical body of mud or earth rose and exploded again. In the same manner this volcanic ebullition goes on without interruption, throwing up a globular body of mud, and dispersing it with violence through the neighbouring plain. The spot where the ebullition occurs is nearly circular and perfectly level, it is covered only with the earthy particles impregnated with salt water, which are thrown up from below; the circumference may be estimated at about half an English mile. In order to conduct the salt water to the circumference, small passages, or gutters, are made in the loose muddy earth, which lead it to the borders, where it is collected in holes dug in the ground for the purpose of evaporation.