riment with infinite delight, and modifying and enlarging it to produce some practical application.

In considering these minuter points, we must never lose sight of the extraordinary perseverance shown by the Marquis throughout a long life, in conducting and varying his experimental inquiries. It was the one pursuit of a studious life-time, the heaviest source of expenditure in his private disbursements. Perhaps we should be very much under the mark in saying that he must have expended above a hundred thousand pounds in experiments alone; which would be represented by nearly ten times that amount in our day. And not only was this outlay very great, but he had for above thirtyfive years kept his workman, Caspar Kaltoff, constantly engaged on his models and on practical trials of his variously constructed inventions.

The Act for his Water-commanding Engine received the Royal assent in June, 1663, and the same year he published his "Century of Inventions" (as here reprinted); a pamphlet was next issued, with no other title than the following heading at the top of the first page. "An exact and true definition of the most stupendious Water-commanding Engine, invented by the Right Honourable (and deservedly to be praised and admired) Edward Somerset, Lord Marquess of Worcester, and by his Lordship himself presented to His most Excellent Majesty, Charles the Second, our most gracious Sovereign."-See Appendix C.

This pamphlet appears to have had some connection with means for giving publicity to the formation of a public company for carrying out the great design on a sufficiently large and remunerative scale. The author, or editor, was James Rollock, who here flourishes in a poetical vein, observing, "After the Act of Parliament, there is here set down a Latin Elogium, and an English

Panegirick, both of them composed through duty and gratitude by an ancient servant of his Lordship's." He afterwards adds: "This ancient servant of his Lordship's, hath for forty years been an eye witness of his great ingenuity, indefatigable pains, and vast expences in perfecting for publique service, not onely this most Stupendious Water-commanding Engine, but likewise several other rare, useful, and never formerly heard of Mathematical conclusions, of which he hath owned a Century, and thereunto I refer you: though this alone were enough to eternalize his Name to all Ages and future times."

The "Definition" given in the pamphlet agrees with that which has already appeared in the "Life, Times, &c.," pages 224, 225, from another source, and is here stated as follows:

"The Engine consisteth of the following Particulars; "1. A perfect Counterpoize for what Quantity soever of Water.

"2. A perfect Countervail for what Height soever it is to be brought unto.

"3. A Primum Mobile commanding both Height and Quantity Regulator-wise.

"4. A Vicegerent or Countervail supplying the place, and performing the full force of a Man, Wind, Beast, or Mill.

"5. A Helm or Stern, with Bitt and Reins, wherewith any Child may guide, order, and control the whole Operation.

“6. A particular Magazine for Water, according to the intended Quantity or Height of Water.

"7. An Aquaduct capable of any intended Quantity or Height of Water.

"8. A place for the Original Fountain or even river

to run into, and naturally of its own accord incor

porate 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 stern, 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* on the opposite page from a sectional drawing designed by the author.

* 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

E, the vertical water pipe by means of

F. F', continuations of the same pipe conducted into and nearly touching the bottom of each vessel A, A'.

G, G', are two water supply pipes, with valves a, a', dipping into

H, the well. It is obvious that by uniting these pipes, and placing the valves in