“8. A place for the Original Fountain or even river to run into, and naturally of its own accord incorporate itself with the rising Water, and at the very bottom of the same Aquaduct, though never so big or high.”
We cannot do otherwise than consider that the articles, Nos. 68, 98, and 100, refer to descriptions of the several parts of his remarkable steam engine. In No. 68, we have the two vessels, with two cocks, connected with a furnace, and so arranged that “one vessel of water being consumed, another begins to force and refil with cold water.” In No. 98, we have intimation of “the primum mobile,” forming the 3rd division of the particulars enumerated above; being some portion of the engine capable of every variety of movement. And in No. 100, we have no mechanical suggestions, but in their place a bare enumeration of results, and of advantages to be derived from the employment of such engines.
What then are we to understand by the preceding list of particulars? “1. A perfect counterpoise,” would suggest that the Marquis had contrived a complete system of pumping; “2. A perfect countervail,” appears to be only a different kind of counterpoise, as though the one were derived from weight, and the other from the action of the steam; 4. “A vicegerent,” may be the force or piston; 5. “A helm or stem, with bit and reins,” can hardly be mistaken for any other than levers, acting on valves, and in some positions connected with chains running over guide pulleys; while the parts 6, 7, and 8, refer wholly to reservoirs, cisterns, and other external arrangements. But this statement is simply made to remind the reader that the Marquis’s Engine was not so entirely simple in its construction as to consist only of a boiler and receiver, and to depend wholly on the effect of the direct action of steam on a large surface of cold water, as generally intimated. It is usual entirely to set aside this full and clear statement of details. So indefinitely has the Marquis’s claim hitherto been stated, that it is always assumed, that while using this early steam engine, he was quite unacquainted with condensation; or, at least, with any mode of employing it to produce a useful effect. On the other hand, it is not only more rational to suppose that he could not be otherwise than fully acquainted with it, but that, having ascertained its various results, he finally succeeded in employing condensation to produce a vacuum for refilling his vessels, and for giving motion to a force or piston. Indeed, we find in the foregoing statement—“6. A particular Magazine for Water, according to the intended quantity or Height of Water.” A particular Magazine, one for a special purpose, for which it was particular to have such a supply; and for size, form, and situation, it had reference “to the quantity and height of water,” for a small cistern would supply sufficient water for condensation, but a larger cistern would be required in proportion to more extended service. Then, “7. An Aqueduct,” might be the vertical main pipe; and “8. A place for the original fountain,” peculiarly arranged reservoirs, with suitable valves, floats, &c.
Uniting his several descriptions, we readily make out a construction of apparatus answering many of the conditions he has stated, as shown in the engraving[W] on the opposite page from a sectional drawing designed by the author.
[[W]] DESCRIPTION OF THE ENGRAVING.
A, A' Two cold water vessels, connected by—
B, B'—the steam pipe, with—
C, the Boiler, set in—
D, the furnace. The cold water vessels A A', also are connected with—