But it often happens that the oil is forced up through the pipe by the pressure of gas in the bowels of the earth, and when I was at Balakhani we often used to go out and look at this singular display. With a deafening roar, a thick greenish-brown jet shot up out of the ground and right through the derrick (Plate III.). It was visible from a long distance, for it might be as much as 200 feet high, and the oil was collected within dams thrown up around. If there was a strong wind the jet would be dispersed, and a dark mist would lie like a veil over the ground to leeward. In Balakhani one can hardly look out of the door without one's clothes being smeared with oil, and the odour can be perceived a dozen miles away. Not a blade of grass grows in this neighbourhood; all that one sees is a forest of derricks. Lines of pipes convey the oil from the borings to the "Black Town" of Baku, which is full of oil refineries (over 170 in all) emitting vast volumes of smoke, black and greasy buildings, and pools of oil refuse. When the crude natural oil is purified, it is distributed far and wide in special railway trucks like cisterns, and in special tank steamers, into which the petroleum is pumped, and which carry nothing else. In the Baku oil-fields there are now (1910) no fewer than 4094 bores, of which 2600 are productive. Last year they yielded about eight million tons of raw petroleum, some of them having sometimes given nearly 300 tons in twenty-four hours by pumping, and 2000 when the oil shot out of the ground itself. The value on the spot is now about 20 shillings a ton. The deepest boring is sunk 2800 feet into the earth. [Illustration: PLATE III. OIL-WELL AT BALAKHANI. A fountain of oil forced up by natural pressure.] Late one evening in February, 1886, the dreadful cry of "Fire! Fire!" was heard outside our house. The very thought of fire is enough to raise terror and consternation throughout this oil-soaked district. We hurry out and find the whole neighbourhood illuminated with a weird, whitish light, as bright as day. The derricks stand out like ghosts against the light background. We make for the place and feel the heat increasing. Bright white flames shoot up fantastically into the air, sending off black clouds of smoke. One derrick is in flames and beside it a pool of raw petroleum is burning. A Tatar had gone to the derrick with a lantern to fetch a tool. He lost his lantern, and only just escaped with his life before the oil-soaked derrick took fire. It is vain to fight against such a fire. The fire-engine came, and all the hoses were at work, but what was the use when the jets of water were turned to steam before they reached the burning surface of the oil pool? The chief thing is to keep the fire from spreading, and if that is done, the oil is left to bubble and burn until not a drop is left. ACROSS PERSIA