stream of water will be somewhat stronger than before, if you pull the handle of the regulator before any considerable quantity of steam be gone up the clack, _r_; but it is much better to let none of the steam go off, for that is but losing so much strength, and is easily prevented, by polling the regulator some little time before the vessel forcing is quite emptied. This being done, immediately turn the cock or pipe of the cistern, _x_, on _p_, so that the water proceeding from _x_, through _y_, which is never open but when turned on _p_, or _P_; but when between them, is tight and stanch; I say, the water, falling on _p_, causes, by its coolness, the steam, which had such great force just before to its elastic power, to condense, and become a vacuum or empty apace, so that the vessel, _p_, is, by the external pressure of the atmosphere, or what is vulgarly called suction, immediately refilled, while _p_ is emptying; which being done, you push the handle of the regulator from you, and throw the force on _p_, pulling the condensing pipe over _p_, causing the steam in that vessel to condense, so that it fills, while the other empties. The labour of turning these two parts of the engine, viz. the regulator and water-cock, and attending the fire, being no more than what a boy’s strength can perform for a day together, and is as easily learned as their driving of a horse in a tub-gin; yet, after all, I would have men, and those, too, the most apprehensive, employed in working of the engine, supposing them more careful than boys. The difference of this charge is not to be mentioned or accounted of, when we consider the vast profit which those who use the engine will reap by it. The ingenious reader will, probably, here object, that the steam being the cause of this motion and force, and that steam is but water rarefied, the boiler, _l_, must in some certain time be emptied, so as the work of the engine must stop to replenish the boiler, or endanger the burning out or melting the bottom of the boiler.