Young Folks' Library, Volume XI (of 20) / Wonders of Earth, Sea and Sky

by Unknown

Conceive a crowd of mushrooms, of all shapes, from ten to fifty feet across, close together side by side, their tops being kept at exactly the same level, their rounded rims squeezed tight against each other; then conceive water poured on them so as to fill the parting seams, and in the wet season, during which we visited it, to overflow the tops somewhat. Thus would each mushroom represent, tolerably well, one of the innumerable flat asphalt bosses, which seem to have sprung up each from a separate centre, while the parting seams would be of much the same shape as those in the asphalt, broad and shallow atop, and rolling downward in a smooth curve, till they are at bottom mere cracks from two to ten feet deep. Whether these cracks actually close up below, and the two contiguous masses of pitch become one, cannot be seen. As far as the eye goes down, they are two, though pressed close to each other. Messrs. Wall and Sawkins explain the odd fact clearly and simply. The oil, they say, which the asphalt contains when it rises first, evaporates in the sun, of course most on the outside of the heap, leaving a thorough coat of asphalt, which has, generally, no power to unite with the corresponding coat of the next mass. Meanwhile Mr. Manross, an American gentleman, who has written a very clever and interesting account of the lake, seems to have been so far deceived by the curved and squeezed edges of these masses that he attributes to each of them a revolving motion, and supposes that the material is continually passing from the centre to the edges, when it "rolls under," and rises again in the middle. Certainly the strange stuff looks, at the first glance, as if it were behaving in this way; and certainly, also, his theory would explain the appearance of sticks and logs in the pitch. But Messrs. Wall and Sawkins say that they have observed no such motion: nor did we; and I agree with them, that it is not very obvious to what force, or what influence, it could be attributable. We must, therefore, seek some other way of accounting for the sticks—which utterly puzzled us, and which Mr. Manross well describes as "numerous pieces of wood, which, being involved in the pitch, are constantly coming to the surface. They are often several feet in length, and five or six inches in diameter. On reaching the surface they generally assume an upright position, one end being detained in the pitch, while the other is elevated by the lifting of the middle. They may be seen at frequent intervals over the lake, standing up to the height of two or even three feet. They look like stumps of trees protruding through the pitch; but their parvenu character is curiously betrayed by a ragged cap of pitch which invariably covers the top, and hangs down like hounds' ears on either side."

Whence do they come? Have they been blown on to the lake, or left behind by man? or are they fossil trees, integral parts of the vegetable stratum below which is continually rolling upward? or are they of both kinds? I do not know. Only this is certain, as Messrs. Wall and Sawkins have pointed out, that not only "the purer varieties of asphalt, such as approach or are identical with asphalt glance, have been observed" (though not, I think, in the lake itself) "in isolated masses, where there was little doubt of their proceeding from ligneous substances of larger dimensions, such as roots and pieces of trunks and branches," but, moreover, that "it is also necessary to admit a species of conversion by contact, since pieces of wood included accidentally in the asphalt, for example, by dropping from overhanging vegetation, are often found partially transformed into the material." This is a statement which we verified again and again, as we did the one which follows, namely, that the hollow bubbles which abound on the surface of the pitch "generally contain traces of the lighter portion of vegetation," and "are manifestly derived from leaves, etc., which are blown about the lake by the wind, and are covered with asphalt, and, as they become asphalt themselves, give off gases which form bubbles round them."

But how is it that those logs stand up out of the asphalt, with asphalt caps and hounds' ears (as Mr. Manross well phrases it) on the tops of them?

We pushed on across the lake, over the planks which the negroes laid down from island to island. Some, meanwhile, preferred a steeple-chase with water-jumps, after the fashion of the midshipmen on a certain second visit to the lake. How the negroes grinned delight and surprise at the vagaries of English lads—a species of animal altogether new to them; and how they grinned still more when certain staid and portly dignitaries caught the infection, and proved by more than one good leap that they too had been English school-boys—alas! long, long ago.

So, whether by bridging, leaping, or wading, we arrived at the little islands, and found them covered with a thick, low scrub; deep sedge, and among them Pinguins, like huge pine-apples without the apple; gray wild-pines, parasites on Matapalos, which, of course, have established themselves, like robbers and vagrants as they are, everywhere; a true holly, with box-like leaves; and a rare cocoa-plum, very like the holly in habit, which seems to be all but confined to these little patches of red earth, afloat on the pitch. Out of the scrub, when we were there, flew off two or three night-jars, very like our English species, save that they had white in the wings; and on the second visit one of the midshipmen, true to the English boy's bird's-nesting instinct, found one of their eggs, white-spotted, in a grass nest.

Passing these little islands, which are said (I know not how truly) to change their places and number, we came to the very fountains of Styx, to that part of the lake where the asphalt is still oozing up.

As the wind set toward us, we soon became aware of an evil smell—petroleum and sulphureted hydrogen at once—which gave some of us a headache. The pitch here is yellow and white with sulphur foam; so are the water-channels; and out of both water and pitch innumerable bubbles of gas arise, loathsome to the smell. We became aware that the pitch was soft under our feet. We left the impression of our boots; and if we had stood still awhile, we should soon have been ankle-deep. No doubt there are spots where, if a man stayed long enough, he would be slowly and horribly engulfed. "But," as Mr. Manross says truly, "in no place is it possible to form those bowl-like depressions round the observer described by former travellers." What we did see is that the fresh pitch oozes out at the lines of least resistance, namely, in the channels between the older and more hardened masses, usually at the upper ends of them, so that one may stand on pitch comparatively hard, and put one's hand into pitch quite liquid, which is flowing softly out, like some ugly fungoid growth, such as may be seen in old wine-cellars, into the water. One such pitch-fungus had grown several yards in length in the three weeks between our first and second visit; and on another, some of our party performed exactly the same feat as Mr. Manross.

"In one of the star-shaped pools of water, some five feet deep, a column of pitch had been forced perpendicularly up from the bottom. On reaching the surface of the water it had formed a sort of centre-table, about four feet in diameter, but without touching the sides of the pool. The stem was about a foot in diameter. I leaped out on this table, and found that it not only sustained my weight, but that the elasticity of the stem enabled me to rock it from side to side. Pieces torn from the edges of this table sank readily, showing that it had been raised by pressure, and not by its buoyancy."

True, though strange; but stranger still did it seem to us when we did at last what the negroes asked us, and dipped our hands into the liquid pitch, to find that it did not soil the fingers. The old proverb that one cannot touch pitch without being defiled happily does not stand true here, or the place would be intolerably loathsome. It can be scraped up, moulded into any shape you will, wound in a string (as was done by one of the midshipmen) round a stick, and carried off; but nothing is left on the hand save clean gray mud and water. It may be kneaded for an hour before the mud be sufficiently driven out of it to make it sticky. This very abundance of earthy matter it is which, while it keeps the pitch from soiling, makes it far less valuable than it would be were it pure.

It is easy to understand whence this earthy matter (twenty or thirty per cent) comes. Throughout the neighborhood the ground is full, to the depth of hundreds of feet, of coaly and asphaltic matter. Layers of sandstone or of shale containing this decayed vegetable alternate with layers which contain none; and if, as seems probable, the coaly matter is continually changing into asphalt and oil, and then working its way upward through every crack and pore, to escape from the enormous pressure of the superincumbent soil, it must needs carry up with it innumerable particles of the soils through which it passes.