Savery now went about the work of introducing his invention in a way which is in marked contrast with that usually adopted by the inventors of that time. He commenced a systematic and successful system of advertisement, and lost no opportunity of making his plans not merely known, but well understood, even in matters of detail. The Royal Society was then fully organized, and at one of its meetings he obtained permission to appear with his model "fire-engine" and to explain its operation; and, as the minutes read, "Mr. Savery entertained the Society with showing his engine to raise water by the force of fire. He was thanked for showing the experiment, which succeeded, according to expectation, and was approved of." He presented to the Society a drawing and specifications of his machine, and "The Transactions"[23] contain a copperplate engraving and the description of his model. It consisted of a furnace, _A_, heating a boiler, _B_, which was connected by pipes, _C C_, with two copper receivers, _D D_. There were led from the bottom of these receivers branch pipes, _F F_, which turned upward, and were united to form a rising main, or "forcing-pipe," _G_. From the top of each receiver was led a pipe, which was turned downward, and these pipes united to form a suction-pipe, which was led down to the bottom of the well or reservoir from which the water was to be drawn. The maximum lift allowable was stated at 24 feet. [23] "Philosophical Transactions, No. 252." Weld's "Royal Society," vol. i., p. 357. Lowthorp's "Abridgment," vol. i. [Illustration: FIG. 11.--Savery's Model, 1698.] The engine was worked as follows: Steam is raised in the boiler, _B_, and a cock, _C_, being opened, a receiver, _D_, is filled with steam. Closing the cock, _C_, the steam condensing in the receiver, a vacuum is created, and the pressure of the atmosphere forces the water up, through the supply-pipe, from the well into the receiver. Opening the cock, _C_, again, the check-valve in the suction-pipe at _E_ closes, the steam drives the water out through the forcing-pipe, _G_, the clack-valve, _E_, on that pipe opening before it, and the liquid is expelled from the top of the pipe. The valve, _C_, is again closed; the steam again condenses, and the engine is worked as before. While one of the two receivers is discharging, the other is filling, as in the machine of the Marquis of Worcester, and thus the steam is drawn from the boiler with tolerable regularity, and the expulsion of water takes place with similar uniformity, the two systems of receivers and pipes being worked alternately by the single boiler.