It was the engine fire of which the foreman spoke, and he was pointing to one of the magnificent steam fire-engines at the headquarters of the London Brigade. [Illustration: HEADQUARTERS, METROPOLITAN FIRE-BRIGADE, SOUTHWARK.] "Here is a steam-match," he continued, "kept in readiness on the engine. It is like a very large fusee, and is specially made for us. Water won't put it out." He strikes the match, and it burns with a large flame. He plunges it into some water near by, and it still continues to burn. It evidently means to flame until the engine fire is burning fast. The wood also is carefully prepared, being fine deal ends, specially cut to the required size; while the coal is Welsh--the best for engine-boilers. These details may seem trivial; but they assist in the rapid kindling of the engine fire, which is not trivial. But the rapid kindling of the fire is not the only reason why the brigade raises steam so quickly in its engines; in addition, a gas-jet is always kept burning by the boiler, and maintains the water at nearly boiling-point before the fire is lighted. This was a method adopted by Captain Shaw. But even this arrangement does not explain everything. [Illustration: SECTION OF A STEAM FIRE-ENGINE BOILER.] To fully understand the mystery, we must leave this smart engine, shining in scarlet and flaming with brass, and go upstairs to the instruction-room for recruits. Here we can see a section of the engine fire-box and boiler. It is very interesting and very ingenious. But probably a novice would ask, "Where is the boiler? I see little else but tubes." That is the explanation. The tubes chiefly form the boiler; for they are full of water, and they communicate with a narrow space, or "jacket," also full of water, and which reaches all round the fire-box. This fire-box is held in a hollow below the tubes, which are placed in rows, one row across the other, just at the bottom of the funnel and above the fire-box. When, therefore, the flaming steam-match is dropped down the funnel, it finds its way straight down between the crossed mass of tubes to the shavings beneath; and the tubes full of the hot water are at once wrapped in heat from the newly-kindled and rapidly-burning fire. Every particle of heat and smoke and flame that rises must pass upward between the tubes. Furthermore, the hot water rises and the colder falls, so that there is a constant circulation maintained. The colder water is continually descending to the hottest tubes; and when bubbles of steam are formed, they rise with the hot water to the top. A space is reserved above the tubes, and around the funnel, called the "steam-space" or "steam-chest," where the steam can be stored; the steam pressure at which the engine frequently works being a hundred and twenty pounds to the square inch. The result of all these ingenious arrangements is that, starting with very hot water, a hundred pounds of steam can be raised in five minutes.