8. F. Pechham—The Pitch Lake of Trinidad. 419 



one to eight rods in diameter. The intervening spaces are Ml of 

 water. These channels (or spaces) have heretofore been described 

 as crevices or cracks in the pitch. This description, however, is 

 incorrect, for the material, though apparently almost as hard 

 as stone, is yet far too plastic to admit of anything like a fissure 

 remaining open in it. The channels are produced and maintained 

 by the following singular process. Each of the many areas into 

 which the lake is divided possesses an independent revolving 

 motion in this wise : at the center of the area the pitch is constantly 

 rising up, not breaking out in streams, but rising en masse. It 

 is thus constantly displacing that which previously occupied the 

 center, and forcing it towards the circumference. The surface 

 becomes covered with concentric wrinkles and the interior structure 

 somewhat laminated. When the edge of such an expanding area 

 meets that of the adjoining one the pitch rolls under, to be thrown 

 up again at the center at some future period. The material is nearly 

 soft enough to meet and form a close joint at the top, but descends 

 with a rounded edge and at a considerable angle. The conclusion, 

 then, to which a close observation leads us in regard to the present 

 condition of this singular lake is, not that it has suddenly cooled 

 down from a boiling state, as heretofore described, but that, as the 

 material is, it is still boiling, although with an infinitely slow motion. 

 As the descent of the glacier may be considered the slowest instance 

 of flowing in nature, so the revolutions of the scarcely less solid 

 bitumen of this lake may be set down as the slowest example 

 of ebullition." 



" Towards the center of the lake several detached areas are met 

 with, the surfaces of which yield under the foot. On standing 

 ten or fifteen minutes one may find himself ankle deep. A person 

 standing long enough would undoubtedly sink and perhaps disappear 

 in it; but in no place was it possible to form those bowl-like de- 

 pressions around the observer as described by former travellers." 



"The water which filled the crevices of the pitch is clear and 

 very pure. It is the favourite resort of all the washerwomen for 

 miles around. As the water is flowing now, the pitch has formerly 

 flowed from the lake in all directions. The entire surface covered 

 by it is estimated at 3000 acres. The pores of the pitch are full 

 of water, which oozes out on the slightest pressure, and by moistening 

 the skin prevents adhesion. Streams of gas issue, sometimes rising 

 through the water, but more frequently from small openings in the 

 pitch above watei'-level." 



" In one of the star-shaped pools of water, a column of pitch 

 had been forced up from the bottom, expanding into a sort of 

 center-table about four feet in diameter. Pieces torn from the 

 edge of this table sank readily, showing that it had been raised by 

 pressure and not by buoyancy." 



" About a mile and one-half south of the lake I observed numerous 

 beds of indurated clay filled with the remains of leaves and vege- 

 tation. A little further on appears a bed of brown coal and lignite, 

 about twelve feet thick. It has such a dip and direction that, if 



