Talk:Thomas Newcomen/Material from Wikipedia user Dr. Gabriel Gojon/The Savery Hoax

The Savery Hoax Despite the publicity given to Papin's invention, the British Parliament awarded an exclusive patent for "Raising Water by the Impellent Force of Fire" to one Thomas Savery, variously described as a "sea captain" and a "military engineer." The terms of the patent meant that any steam- powered device Papin might invent in England would come under the control of Savery. Although news of Savery's patent reached Germany by 1699, it was not until 1704 that Leibniz, via "Hanoverian envoys" in London, was able to acquire some sort of description of Savery's device. Leibniz forwarded a sketch of the English "engine" to Papin, along with an evaluation of its capabilities. Based on further intelligence reports from his envoys, Leibniz concluded that Savery's device could not work in full size.

Savery's "engine" consists of a chamber connected by a pipe to a source of water below, and by another pipe to a separate boiler. Steam enters the chamber from the boiler; cold water is poured on the chamber, condensing the steam, thus creating a vacuum and drawing water up the pipe from below. The steam enters the chamber again, this time for the purpose of pushing the raised water out of the chamber, and up another pipe. The steam is then forced to condense once again, creating a vacuum, and sucking more water up from below, renewing the cycle (see Figure 7).

For Leibniz and Papin, study of Savery's design provided a unique opportunity to apply and improve their new thermodynamic principles, since Savery was proposing precisely the sort of containment of steam power, within the conceptual and technological boundaries of mechanics, against which Leibniz had warned.

Papin wrote to Leibniz, describing experiments in which he had discovered that, using Savery's design, an increase in the temperature of the steam actually resulted in a decrease of the work performed (July 23,1705):

I am persuaded that it will be useless to try to push water to great heights by the immediate pressure of steam: Because when the expanded steam strongly applies itself against the cold water, as is necessary to make it rise to a great height, it isn't possible to conserve the force of the steam; but it is immediately condensed by the coldness of the water. And the hotter the steam is, the more it violently pushes the valve, in such a way that the valve, being pushed as well by the spring which is behind, causes the water to become very agitated. The water thus agitated is much more likely to cool off a lot of steam than when its surface remains smooth. Thus I firmly believe that this is the reason which makes the elevation of the water decrease when the heat increases .... I therefore believe that the best is to do it so that the steam doesn't directly touch the water, but that it pushes it only by the mediation of a piston which is quickly heated, and which consequently only condenses a little steam. And the surface of the piston which touches the steam always stays the same, the new steam which frequently reaches it easily maintains it in a degree of heat all the more great as the steam is hot. Thus there is no fear that the machine's effect will fail to be augmented in proportion to the increase in heat. Experiment has well confirmed my conjecture....

And the more I go forward, the more I wonder at how a small quantity of wood is capable of furnishing such force.... But... it would be desirable to work at that with more heat than made [now]: seeing principally that the use of this invention isn't limited to raising water, but that it could be applied very well to vehicles and to many other things where force is needed."

Leibniz fully approved of Papin's successful application of his thermodynamics, advising him not to take Savery's claims of success too seriously (Aug. 15,1705): I am delighted that your fire engine advances so well, because when it is brought to perfection, I consider that it will be very useful. Also, it would be a mere trifle if only one-third of the expense would be saved, as the English author believed, since this advantage would be easily absorbed by other inconveniences which such a great alteration of machines would attract. It is very reasonable also to believe that too diffuse steam applied directly to cold water will condense and lose its force. Consequently, it is better to keep them self-contained [renfermees]. According to the Royal Society myth, this sort of reasoning about the steam engine was not supposed to have occurred until about 1769, when James Watt recognized the problem of loss of force because of superfluous cooling of the steam, and invented a separate condenser. Watt was motivated in this invention by the knowledge that the Newcomen engine would operate much more efficiently, if its cylinder was kept constantly hot, while the condenser was kept constantly cold; that is, "it is better to keep them [steam and cold water] self-contained." In effect, Savery proposed to doom steam to play the role of the ancient horse-driven windlass (hoist) and pulley, slowly pulling water up one pipe and pushing it out of another, with one significant difference - Savery's "fire engine" was much more expensive.

Savery's fraud was recognized as such by crafty miners, and his engine was used mostly to raise water for the fountains wealthy aristocrats. As even the British historian A. Wolf admits, "It was costly and dangerous, so the mine owners stuck to horses."

Savery included an interesting comment on ships in his second chapter, "Of the Uses That This Engine May Be Applied Unto," indicating that it apparently had been made clear in England that the authorities would frown on any drastic technological advance in this area. As Robert Fulton later understood, a successful steamship could be the greatest threat to continued Anglo-Dutch commercial and naval superiority.

Savery fearfully noted, "5. I believe it may be made very useful to ships, but I dare not meddle with that matter, and leave it to the judgment of those who are the best judges of maritime affairs."

A few pages later, he added, "As for fixing the engine in ships, when they may be thought probably useful, I question not but we may find conveniency enough for fixing them."

These two timid-passages apparently constitute the totality of published British commentary on the steamship during most of the 1700s. Meanwhile, Leibniz had become fully committed to seeing a steam-powered vehicle perfected and built within his lifetime -whether a steam boat, a steam carriage, or an airplane. But while Savery and his colleagues could obstruct science at their leisure in the relative peace and quiet of Gresham College, Leibniz and Papin struggled to advance science as rapidly as possible, living in the direct line of march of an invading French army.