FIREDAMP

the name applied by miners to coal gas or light carbureted hydrogen. It comes from the crevices in the mines, being formed in the coal, and when mixed with the air in a certain proportion is highly explosive, causing many accidents. FIRE ENGINES. A mechanically operated, mobile pump used to pump water for fire extinguishing purposes. The use of machines of this nature dates back to the Roman and other early civilizations. No description is available of the old Roman machine, but the Egyptians had a crude sort of manually operated two cylinder pump, which delivered the water in a series of impulses or squirts. This intermittent flow was due to the absence of air chambers, which together with hoses made of leather came into use in the 17th century. Paris had fire engines of a sort at the beginning of the 18th century. These were manually operated, and were drawn to the fire by man power. Newsham introduced his English engine, also manually operated, into New York City in 1731. Floating fire engines were in use on the Thames in England at this time (these were the forerunners of the present fireboats). Hand operated fire pumps came into common use after this time; and were superseded only by the advent of the steam engine. In 1850, A. B. Latta of Cincinnati built the first steam fire engine which was dependable and practical. This engine with its steam boiler was mounted on a special truck, drawn by horses, and was used extensively in the larger cities. In 1877 a steam driven, steam propelled engine was proposed, and several were built and used in New York City and Boston. It was not a great succe , horses being much more reliable for the purpose. Motor driven engines, with either steam or motor driven pumps are coming into general use at present, and have completely replaced the older steam engines in the larger cities. The modern steam fire engine consists of a boiler with the nece ary firebox, flues, apparatus for supplying water to the boiler, etc., mounted on a truck with a ‘steam engine and pump. The boiler is usually of the vertical water tube type, and designed for easy steaming The engine generally of the vertical double acting type, has two cylinders. The pump is also of the vertical, double acting type and is in duplicate. Centrifugal pumps are rarely used. The capacity of the pump varies with the size of the engine, and also with the pre ure of the water. The usual range is from 400 to 1300 gallons per minute, or 5000 to 11000 lbs. per hour. The pump draws water from the water main through the ‘fire hydrant,’ and delivers it to one or more hose lines which are directed into the burning building. Many cities have high pre ure water systems which need to be supplemented by a fire engine only when the water is to be used in a very high building. In order that the engine may be ready to pump water immediately upon its arrival at the fire, heaters are installed in the fire house which always keeps the water in the boiler at or near the boiling point; and when the engine leaves the fire house the fire is kindled with oil soaked rags and wooed.