. The Popular science monthly . Photo, C. R. Toothaker, Phila. Commercial Asphalt Rising through Water. The surface of the deposit or lake is not a uniform expanse of is grassy along the edges and becomes free from vegetation at somedistance from the center. Shrubs and small trees occur in a fewcases known as islands. These patches move from place to place withthe movement of the pitch at the surface. The main mass of asphalt is abroad expanse of pitch made up of separate areas of irregular outline, butat times quite circular, which are separated by channels, filled with r
. The Popular science monthly . Photo, C. R. Toothaker, Phila. Commercial Asphalt Rising through Water. The surface of the deposit or lake is not a uniform expanse of is grassy along the edges and becomes free from vegetation at somedistance from the center. Shrubs and small trees occur in a fewcases known as islands. These patches move from place to place withthe movement of the pitch at the surface. The main mass of asphalt is abroad expanse of pitch made up of separate areas of irregular outline, butat times quite circular, which are separated by channels, filled with rainwater, which prevents their coalescence. The boundaries are depressedand the center of the areas is always somewhat elevated above theedges, that is to say, they are mushroom-like. The origin of the separateareas evidently lies in the constant movement of the crude material, due. Photo, C. R. Toothaker, Phila. Commercial of Gas in Water. TRINIDAD AND BERMUDEZ ASPHALTS 23 to the evolution of gas at the center, from which point the pitch rollsover toward the edges. This is shown by the fact that pieces of woodwhich emerge erect at the center are gradually carried to the circum-ference, their deflection from the perpendicular increasing as the dis-tance from the center increases. At the channel they topple over and areagain engulfed in the pitch. This illustrates very well the activity ofthe entire surface of the deposit, although it is much more active nearthe center of the lake. As to the depth of the lake, borings made in 1894 at the center,were carried to a depth of 135 feet, by means of a wash drill, the entiredistance being through asphalt of the same character as that at the sur-face. This result shows the great depth of the crater, and the uni-
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