[Illustration: A near view of the surface of the lake. Gas emerging through surface water, as shown by ripples and bubbles] [Illustration: Uncovering land asphalt. The difference between lake and land asphalts can be seen readily] [Illustration: The narrow boardwalk, forty feet above the water, and the conveyor cable with loaded buckets of asphalt. Men throwing off the clutch.] [Illustration: The next step—Men releasing the pawl preparatory to emptying the large bucket.] [Illustration: The bucket is tipped up and the asphalt goes tumbling through a hole in the platform, down a chute into the hold of the ship.] The origin of asphalt has been a subject of much discussion in the past, and recent developments in the region of the lake enable one at last to make a definite statement on the subject. Strata of clays and shales that extend from east to west in southern Trinidad, carry asphaltic oil in liquid form. Many wells have been drilled in recent years and quantities of this maltha won. The asphalt lake fills a natural depression into which asphaltic petroleum from one of these strata found its way ages ago. A geologist might say that the origin of the deposit of asphalt is recent, but in saying that he might mean that not more than a few thousand years had gone since its occurrence. The asphaltic petroleum came from the depths, after which such parts of the substance as were light and gaseous volatilized, the heavy base remaining. For practical purposes the asphalt is a perfect commodity for the uses to which it is applied. The amount in the lake has not been calculated with any certainty, but there is unquestionably enough to supply the needs of the whole world for a very long time. The first modern Trinidad Lake asphalt pavement was laid in the United States. Since then it has been used on show streets of the world, including Fifth Avenue, New York; Pennsylvania Avenue, Washington, D. C.; Michigan Avenue Boulevard, Chicago; Broad Street, Philadelphia; Victoria-Thames Embankment, London, England, and countless other streets in the United States, South America, Australia, Egypt, India and Japan. One very frequently now sees motor trucks hauling mixtures of this black material. Almost everybody has seen it dumped smoking hot on the street, paused to watch the men raking it out carefully and the rollers compressing it into a smooth pavement. As laid it contains 10% of asphalt and the rest is sand and stone-dust. [Illustration: Upper Illustration—Wells, derricks, and partial view of Oil Refinery Lower Illustration—A well in operation, with oil running into “sump” shown in foreground] Nevertheless, the asphalt has such cementitious qualities that it solidifies the materials into a sheet as hard as rock.