Page:The American Cyclopædia (1879) Volume VII.djvu/219

 FIKE ENGINE 211 niently used, the water was supplied to the cistern by buckets passed by hand. Modern engines consist essentially of two vertical double- acting force pumps (see PUMP), one under each end of a lever beam (or sometimes four single- acting pumps), to which are attached long brakes for many men to take hold of and work by hand. The pumps discharge into one res- ervoir, the upper part of which contains air, that acts as a spring to cause the water alter- nately introduced by each pump to flow in a uniform current through the discharge pipe. This pipe opens in the reservoir below the sur- face of the water, and leads without to any required distance, according to the number of lengths of leathern hose that may be attached together by the brass couplings with which they are furnished. The water is discharged through a tapering metallic pipe, upon the end of which is screwed a tip of any required bore, which is held in the hand to direct- the stream upon the fire. A suction pipe from the lower end of the force pump is always ready to be used when necessary ; but where a stream of water with sufficient head, as from the aqueduct hydrants, can be introduced, the suction pipe is not re- quired. The machine is attached to a carriage constructed expressly for the purpose, and fur- nished with various implements such as are likely to be wanted in conflagrations. The brakes are long wooden arms extending over the wheels each way beyond the extremities of the engine, or sometimes transversely to the car- riage, and attached at right angles to the lever beams, which are arranged along the horizontal axis placed over the centre of the carriage. They are moved up and down by men standing on the ground each side of the engine, working with Self-propelling Steam Fire Engine. others who take their position on the top. The great modern improvement in fire engines is the application of steam power to work them. This was first attempted by Mr. Brath- waite, in London, in 1830. His first engine was of barely six-horse power, weighing a lit- tle over 5,000 Ibs., was furnished with an up- right boiler, in which steam was generated to a moderate working pressure in 20 minutes, and was capable of forcing about 150 gallons of water per minute from 80 to 90 ft. in height. It had a steam pump of the same form as those now in common use, the steam and water pis- tons being on opposite ends of the same piston rod, the former being 7 in. in diameter and the latter 6 in., and the stroke of each 16 in. A larger engine of the same general construc- tion was built by Brathwaite in 1832 for the king of Prussia ; but though its performances were highly spoken of, this attempt to apply the power of steam for fire-engine purposes cannot be said to have been successful. The time required for raising steam, and the great weight of the apparatus when adequate boiler power was obtained, were undoubtedly the principal difficulties. In New York, after the great fire of 1835, premiums were offered for plans of steam fire engines, and in the year 1841 an engine was built, from plans by Mr. Hodges, under a contract with the associated insurance companies, and was on several occa- sions brought into service at fires with good effect; but though very powerful, its great weight proved to be a fatal objection, and it