The Caspian is filled with various kinds of fish, and while bathing one might reasonably have the impression that he was swimming in an aquarium. In fact, this place is an ideal one for an Izaak Walton. On the islands beyond the peninsula, projecting out from the Baku section, petroleum gas has flamed for centuries, lighting the heavens at night with a lurid glare that is visible far out at sea. In Baku Bay, between two peninsulas, there was a spot, now commercialized into a producing oil well, where the gas came to the surface with sufficient force to upset small boats. Many of the oil wells are spouters for a long time after they are first bored, and when they cease to spout they can frequently be made to renew their activity by deeper boring. Wells have been pumped for years without the level of the oil being lowered in the slightest. Some of the wells which have caught fire accidentally have burned for years, sending up their pillars of fire to a great height. In a few instances the richest wells have made the owners practically bankrupt by overwhelming the buildings on adjoining property with sand and petroleum, spreading ruin far and wide before the flow could be checked. A majority of the great oil wells are about ten miles from Baku, and a dozen pipe-lines convey the petroleum from them to Black Town, a suburb of Baku, where it is stored and refined. From one well alone the escaping oil would have brought more than five million dollars had it been saved. Seemingly the crust of the earth for hundreds of miles around acts like a huge gasometer pressing down on the pent-up gases with its weight. Since the Caspian Sea is eighty feet below sea level, it is probable that the land bordering the sea has sunk since the gases and oil were formed. And this would, in part at least, account for the enormous pressure. The spouting oil wells are called fountains. Some of them have yielded two million gallons each day for months, sending up jets three or four hundred feet high with a roar that could be heard several miles away. Great difficulty was found at first in stopping the flow when necessary by capping or gagging the wells, but after a time a sliding valve-cap was invented, capable of checking the flow of the most violent well. In order to prevent the enormous pressure from bursting the pipe and tearing up the ground, as soon as the pipe has been sunk part way the earth is excavated around it and the excavation is filled with cement. [Illustration: Landing-place for commerce on the Caspian Sea] It is said that one of these gushers threw up in a day more oil than is produced by all the wells in the United States. One well spouted oil for months before it could be gagged, and in the meantime flooded the surrounding country. Millions of gallons were burned to get rid of it and millions more were diverted into the Caspian Sea. Two wells are reported to have thrown up in less than a month thirty million gallons each.