FIRE ENGINE

This most useful machine is construct ed in a variety of forms, which nil, however, agree in one principle. It generally consists of a double forcing pump communicating with the same air ve el: and instead of a force-pipe a flexible leathern hose is used, through which the water is driven by the pre ure of the condensed air in the air ve el. The annexed diagram represents a section of the apparatus. The pipe T descends into a receiver or ve el containing a supply of wate i. " This pipe communicates with two sucP tion valves V, which open into the pump barrels of two forcing pumps A, B. in which solid pistons P, are placed. The piston rods of these are connected with a working beam F, elongated so that n n number of persons may work at both ends of it at once. Force-pipes t, t. pro ceed from the sides of the pomp barrel above the valves V, and they communicate with an ail ve el M, by means of forcing valves V, which also open *pwards. The pipe descends into the air ve el near the bottom. This pipe is connected with the flexible leathern hose L, the length of which is adapted to the purposes to which the machine is to be applied. The extremity of the hose may be carried in any direction, and may be introduced through the doors and windows of buildings. By the alternate action of the pistons, water is drawn through the suction valve, and propelled through the forcing valves, until the air in the top of the ve el M is highly compre ed. The pres sure acts on the sin face of the water in the ve el, and forces it through the leathern hose in a continued stream, so as to [s. 470]