THE MUSEUM. 



209 



even where quite soft, it will not soil 

 the hands, because the water oozes 

 out and prevents adhesion. 



The pitch is quarried by excavating 

 areas 30 or 40 feet square to a depth 

 of two to four feet. x-Vs soon as the 

 Avork ceases on one of these excava- 

 tions, the asphalt begins to obliter- 

 ate it, the walls not closing in percep- 

 tibly, but the bottom rising up, and in 

 a few days no trace of the opening re- 

 mains. This is one of the many indi- 

 cations of greater fluidity below the 

 surface. 



Toward the center of the lake are 

 several detached areas, a rod or two 

 in breadth, which are softer than the 

 rest of the surface, and yield under 

 the feet, "so that, on standing a few 

 minutes, one feels that he is gradually 

 settling down, and in the course of 

 ten or fifteen minutes, he may find 

 himself ankle deep." "But," as Mr. 

 Manross truly says, "in no place is it 

 possible to form those bowl-like de- 

 pressions around the observer describ- 

 ed by former travelers." Nor is it 

 probable that Kingsley is right in say- 

 ing, "No doubt there are spots where, 

 if a man staid long enough, he would 

 be slowly and horribly engulfed." The 

 inferior density of the human body 

 would prevent its submergence, even 

 if the pitch were quite fluid. 



In the vicinity of these places many 

 small streams of gas escape from the 

 pitch. The evil smell, and the depos- 

 it of sulphur left of the pitch, tell us 

 that the gas is chiefly sulphuretted hy- 

 drogen; but the sulphurous odor ceases 

 to be perceptible at a distance of a 

 few rods, and does not extend for ten 

 or twelve miles, as some writers have 

 asserted. 



The surface of the lake does not 



present a continuous sheet of asphalt, 

 but it is traversed by a net work of 

 channels in which the rain water col- 

 lects. These unite and dmde most 

 curiously, forming one connected sys- 

 tem, and dividing the pitch into nu- 

 merous flat-topped or slightly convex 

 areas or islands, which are usually of 

 quite irregular outline, though some- 

 times nearly circular, and from 10 to 

 100 feet in diameter. A piece of 

 marbled paper would give an excellent 

 idea of the appearance of the lake. 

 The sides of these channels are convex, 

 presenting curves of great regularity 

 and beauty; and, where three or four 

 channels meet, a star-shaped depres- 

 sion is formed. 



Several explanations of this peculiar 

 structure of the lake have been propos- 

 ed. Each of the many hundred areas 

 in which the lake is divided possesses 

 an independent revolving motion, in 

 this wise: In the center of the area 

 the pitch is constantly rising up en 

 masse displacing that which previously 

 occupied the center, and forcing it to- 

 wards the circumference. Where the 

 edge of such an expanding area meets 

 that of the adjoining one, the pitch 

 rolls under, to be thrown up again in 

 the centre at some future period. 



We find unique and conclusive evi- 

 dence of this revolving process in ' 'nu- 

 merous pieces of wood, which being 

 involved in the pitch, are constantly 

 coming to the surface. These frag- 

 ments of wood are of the same recent 

 origin as the leaves and twigs contain- 

 ed in the vehicles of the pitch. From 

 the surrounding forests, or the green 

 islands of the lake itself, they have 

 found their way into the water-chan- 

 nels, become water-logged, sunk to the 

 bottom, and been drawn up again by 



