Sir Hugh Plat, in his “Jewel House of Art and Nature,” 1594, gives an account of the ordinary fire-blowing Æolipile. He says:—“A round ball of copper or lattin, that will blow the fire very strongly, only by the attenuation of water into air; which device will also serve to perfume with.—A round ball of copper or lattin, of the bigness of a small bowl—a round pipe or neck, of 3 or 4 inches in length, less than a goose quill—and an elbow of a less pipe no bigger than a straw, whose vent in the end must be no bigger than a pinhole.” “Heat the same well in the fire, and then put it into a vessel of cold water, and it will suck some of the water into it, you may heat the same so often, till by the peize (poise?) thereof you may be assured that it is more than half full. Then set this ball on a few glowing coals, and you shall find the same to give a very strong blast.... I make no question but that the same may be made so large as that they will blow one whole hour together without any intermission.”—Page 25.
In the second edition of Dr. French’s “Art of Destillation,” 1653, page 150, he describes the “Philosophicall Bellowes:” one is to blow a furnace fire; another a candle, serving as a blow-pipe; and the third for a common fire. He notes “that these kind of vessels must be made of copper, and be exceedingly well closed, that they may have no vent but at their noses.” He recommends, in preparing them for use, that “you must first heat them very hot, then put the noses thereof (which must have a very small hole in them, no bigger than a pin’s head may go in) into a vessel of cold water, and they will presently suck in the water, of which being then full turne the noses thereof towards the candle or fire which you would have blown.”
The third figure, instead of being a copper ball is formed like the human face, and is held by a long stick or handle attached to the back. It is represented and described by Schwenteri, in his “Deliciæ Physico-Mathematicæ,” 1638, along with two tubulated balls for similar use.
Such then were the suggestions the Marquis had before him to excite his experimental inquiries, independent of other sources. But whatever he may have known on the subject of these applications of steam, however much he may have experimented on them, there are two things, of which no one has yet given him the credit of possessing any knowledge whatever, the one is, condensation; the other, a piston. How the Marquis of Worcester could have been experimenting at the cost of £50,000, and upwards, at Vauxhall, and been occupied in this particular class of experiments during a large portion of thirty-eight years, in perfect ignorance that cold water will condense steam, is past all comprehension. Nay, such ignorance would be a greater matter of surprise, than the exhibition of his utmost ingenuity in the mechanical contrivances connected with his engine. Condensation was no mystery. Every work on distillation spoke on the subject, and supplied the forms of refrigeratory worms, and refrigerating heads for alembics. His very allusion to the strength of his vessels must have had reference, first to internal distension, as well as to collapse from external pressure.
John Bate, in his first book, “Of Water Works,” describes a kind of weather glass, which he calls, “the moveable perpendicular glass;” for the construction of which his directions are—“First prepare the glass A, B, fill it almost top full of water, provide also the glass K, L, having a loop at the top of it: divide it into so many equal parts as you would have degrees, and on the mouth thereof fasten a thin board, that will easily slip in and out of the bottom glass; make then a weight of lead or brass somewhat heavier than both the glass and board fastened thereunto; and then tie a little rope to the loop of the glass A, B, and the weight at the other end thereof. Rarifie the air contained in the glass L, and reverse it into the glass A, B, filled with water, and hang the plummet over two little pulleys fastened in a frame made for the purpose; and as the glass K, L, cooleth, the water will ascend the same, and so by the change of the outward both the glass and water will move accordingly.”—Pages 42–43.
From all that has been advanced, an impartial reader must feel satisfied that there existed abundant sources of popular information, highly suggestive to such an inquisitive and inventive mind as the Marquis possessed. Van Etten mentions the filling of a cannon with water, the plugging it up, and exploding it by the action of fire applied to its trunnion. And here John Bate suggests an experimental apparatus on a small scale, which the Marquis would be almost certain to test, and in so doing to vary the construction and application. Rarefaction too is here recommended; and the effect of cooling or condensation is particularly noted, the stated result being, “the water will ascend.” We can readily imagine the Marquis varying such an experiment 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 thirty-five 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 stupendous 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.]