“A, is the furnace; B, the boiler; C, two cocks which convey the steam from the bottom in order to discharge it again at the top; D, which convey the steam by turns, to the vessel D. the vessels which receive the water from the bottom in order to discharge it again at the top; E, valves; F, cocks which keep up the water, while the valves on occasion are cleaned; G, the force pipe; H, the sucking pipe; and I, the water.”
Neither at the time nor afterwards does the invention appear to have attracted any further notice in that quarter. The next account we have of it is afforded by “The Miners Friend, or an Engine to raise Water by Fire,” by Thomas Savery, Gent., 1702; in which the invention appears with two furnaces, instead of one, and with other details. In his description he refers to two vessels, marked P, No. 1, and P, No. 2, which correspond with the two receivers above, marked D, D.
Remarking on these, in “The Miners Friend,” Savery says:—“So that P, No. 1, is by the external pressure of the atmosphere, immediately refilled, while P, No. 2, is emptying; which being done, you push the handle of the regulator from you, and throw the force on P, No. 1, pulling the condensing pipe over P, No. 2, 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 tending the fire, being no more that what a boy’s strength can perform for a day together * * * yet, after all, I would have men. * * *”
In the above 68th Article, the Marquis of Worcester says:—“A man that tends the work is but to turn two cocks, that one vessel of water being consumed, another begins to force and refil with cold water, and so successively, the fire being tended and kept constant, which the self-same person may likewise abundantly perform between the necessity of turning the said cocks.”
And in No. 100, he says, “a child’s force bringeth up an hundred feet high, an incredible quantity of water.”
We do not purpose to press any charge against Savery, but simply to relate what is on record respecting the engine he put forward; and to notice here the remarkable coincidence between his description, and that given by the Marquis 32 years before. The Marquis writes in the singular number of “the fire,” thereby indicating a single furnace; and in Savery’s first drawing we find the model represented with one furnace. Then in “The Miners Friend,” we have parts described agreeing precisely with the preceding article, No. 68. And at the particular point just quoted, we have even a closer analogy, in the use of the very same words in reference to the same parts—turning and tending. And while, in No. 100, the Marquis informs us what “a child’s force” can perform; here Savery speaks of “a boy’s strength,” which is enlarged on, however, by recommending a man’s services.
The next earliest notice we find of this engine is given by Richard Bradley, F.R.S., in his “New Improvements of Planting and Gardening,” 8vo. 1718, who, in the third part, at page 175, supplies an engraving of “the late Mr. Savory, F.R.S.,”[N] his engine, as set up by him “for that curious gentleman Mr. Balle of Cambden House.” It is represented as a spherical boiler, capable of holding forty gallons, supported on a tripod, with a fire on the ground underneath. It is connected with a bell-shaped receiver of thirteen gallons capacity, supplied below with a pipe sixteen feet long, and above with a pipe to elevate the water, forty-two feet. The steam pressure is stated to be capable of discharging fifty-two gallons per minute, the pipes being of three inches bore; and the original cost of the whole was £50.
In 1729, Stephen Switzer published his “Introduction to a general system of Hydrostaticks,” in two volumes quarto. He says:—
“Amongst the several Engines which have been contrived for the raising of water for the supply of houses and gardens, none has been more justly surprising than that of the raising of water by fire; the particular contrivance and sole invention of a gentleman, with whom I had the honour long since to be well acquainted; I mean the ingenious Captain Savery, some time since deceased, but then a most noted engineer, and one of the Commissioners of the Sick and Wounded. This gentleman’s thoughts (as appears by a preface of his to a little book, entitled, ‘The Miners’ Friend’), were always employed in Hydrostatics and Hydraulics; and the first hint from which it is said he took his engine, was from a tobacco pipe, which he immersed to wash or cool it, as is sometimes done; he discovered by the rarefaction of the air in the tube by the heat or steam of the water, and the gravitation or impulse of the exterior air, that the water was made to spring through the tube of the pipe in a wonderful surprising manner; though others say, that the learned Marquis of Worcester, in his ‘Century of Inventions,’ (which book I have not seen), see page 68, gave the first hint for this raising water by fire.”—Vol. ii. p. 325.