“68. An admirable and most forcible way to drive up water by fire, not by drawing or sucking it upwards, for that must be as the Philosopher calleth it, _Intra sphæram activitatis_, which is but at such a distance. But this way hath no Bounder, if the Vessels be strong enough; for I have taken a piece of a whole Cannon, whereof the end was burst, and filled it three-quarters full of water, stopping and scruing up the broken end; as also the Touch-hole; and making a constant fire under it, within twenty-four hours it burst and made a great crack: So that having a way to make my Vessels, so that they are strengthened by the force within them, and the one to fill after the other, I have seen the water run like a constant Fountaine-stream forty foot high; one Vessel of water rarified by fire driveth up forty of cold water. And a man that tends the work is but to turn two Cocks, that one Vessel of water being consumed, another begins to force and refill with cold water, and so successively, the fire being tended and kept constant, which the self-same Person may likewise abundantly perform in the interim between the necessity of turning the said Cocks.” From this account we gather that the Marquis had contrived a plan for raising water by the expansive force of steam, after the manner of De Caus, but with important modifications and improvements. It had obviously occurred to him, that by generating the steam in a separate vessel, and conveying it by means of a suitable pipe to a second closed vessel, he could thereby make it expel the water which the latter contained by pressing upon its surface, as in De Caus’s apparatus. The admission of the steam could easily be regulated by the turning of two cocks; one to admit the steam from the boiler, and the other to allow the exit of the water. On the expulsion of the water, and the production of a vacuum by the condensation of the contained steam, the empty vessel would at once be refilled by the action of the atmospheric pressure on the surface of the water to be raised. It is probable that this engine was--in the absence of a feed-pump, of which there is no mention--provided with two boilers as well as with the two cisterns in which the “forcing and refilling” went on, so as to maintain the “constant fountain-stream” which the Marquis describes. But the precise arrangement of parts by which he accomplished this object must ever remain a matter of mere conjecture. We have other distinct indications of a steam-engine in the Marquis’s 98th, 99th, and 100th Articles, which ought to be read in connection with the 68th Article: they run as follows:--