Note 32 — Chapter III · Captain Savery—His Fire-engine.

Two boilers, a large, A, and a smaller, B, were fixed in a furnace, and connected together at the top by a pipe, C. The larger boiler was filled two-thirds full, and the smaller quite full of water. When that in the larger one was raised to the boiling-point, the handle of the regulator, D, was thrust back as far as it would go, by which the steam forced itself through the pipe connected with the vessel E, expelling the air it contained through the clack at F. The handle of the regulator being then drawn towards you, the communication between the boiler and the vessel, E, was closed, and that between the boiler and the second vessel, G, was opened, which latter was also filled with steam, the air being in like manner discharged through the clack, H. Cold water was then poured from the water-cock, I, on to the vessel E, by which the steam was suddenly condensed, and a vacuum being thereby caused, the water to be raised was drawn up through the sucking-pipe, J, its return being prevented by a clack or valve at K. The handle of the regulator D being again thrust back, the steam was again admitted, and pressing upon the surface of the water in E, forced it out at the bottom of the vessel and up through the pipe L, from which it was driven into the open air. The handle of the regulator was then reversed, on which the steam was again admitted to G, and the water in like manner expelled from it, while E, being again dashed with cold water, was refilling from below. Then the cold water was turned upon G, and thus alternate filling and forcing went on, and a continuous stream of cold water kept flowing from the upper opening. The large boiler was replenished with water by shutting off the connection of the small boiler with the cold water pipe, M, which supplied it from above, on which the steam contained in the latter forced the water through the connecting pipe, C, into the large boiler, and kept it running in a continuous stream until the surface of the water in the smaller boiler was depressed below the opening of the connecting pipe, which was indicated by the noise of the clack, when it was refilled from the cold water pipe, M, as before.