Papin first observed that aqueous vapour furnished a simple means of rapidly creating a vacuum in the space contained in the cylinder.

Papin is the first person who thought of combining in the same machine operating by fire, the action of the elastic force of steam, with the property which steam possesses, and which he has described, of condensing by cooling.*

1698. Captain Savery.

We have no proof that Solomon de Caus ever caused his steam engine * Messrs. Stuart and Partington have explicitly recognized all these claims of Papin to the gratitude of mechanicians; but, by way of equivalent, those who read Dr. Robison's History of the steam engine (see the last edition with the comments of Watt) will there find, p. 49, that the first publication of Papin upon steam machines appeared in 1707; that this machinist did not propose to employ a true piston but a simple float; that he had never dreamed (and here was the important point) of producing the descending motion of the piston by the condensation of steam. These declarations are also made in Dr. Rees' Cyclopedia, article Steam Engine. The author of this article has read in the Acts of Leipsic, a description of the machine in which Papin attempted to produce a vacuum by the aid of gunpowder, for he quotes it; but, by a singular fatality, the mention inserted in the same Acts, of Papin's substituting steam for powder did not attract his attention, since he declares that the apparatus of the French machinist was never intended to be worked by steam.

Mr. Millington is hardly more favourable to our countrymen whose ideas, he says, upon the means of producing a motive power by the aid of steam are all posterior to Savery's patent (p. 255); (Savery's patent was issued in 1698.) Mr. Lardner assures us equally in the lectures which he has recently published, that the French ground their pretensions to the invention of the first steam engine, upon a work of Papin's which did not appear until 1707, nine years after the date of Savery's patent. This remark, he adds, settles the question entirely; Papin has no right to any share in the invention of the steam engine. (Voyez Leçons Sur la machine à vapeur, p. 96, 97, et 101 de l'édition française.)

Is it not really singular that the greater part of the English authors persist in this way in citing only one of Papin's works, that of 1707; that they will make no account of the much more voluminous work from which I have borrowed several passages, and of which two editions appeared in the same year, 1695, one at Cassel in French, and the other at Marburg in Latin; that all the records of this author inserted in the Acts of Leipsic appear to them as if they had never existed!

I will grant, if they will, that there was no piston, properly so called, in the draining machine of 1707; that the condensation of steam had nothing to do with it; that, at all events, the machine is of posterior date to Captain Savery's patent; but these concessions lead to no conclusion, since we do not cite the work of 1707, but a collection of 1695, and the Acts of Leipsic of 1690. Bossut derives his authority, in his Hydrodynamique, for attributing to Papin an important part in the invention of the steam engine, from the work of 1695; Robison answers that this work does not exist! ("The fact is that Papin's first publication was in 1707.") I might conceive of a declaration that he had never seen it, but this flat denial, opposed to the positive assertion of Bossut, was the more strange, because Papin's book is not scarce in England, and because, at all events, the Acts of Leipsic which contain the substance of it, are to be found in the principal libraries, and finally because this work, the existence of which is denied by the celebrated Edinburgh professor, was announced and reviewed in March 1697, in the Philosophical Transactions, a year before any thing was said about Savery's engine. It should not be forgotten that the review of the Philoso phical Transactions gives, in another place, that passage in Papin's work which relates to the employment of steam, in the first place as a means of working the piston, and afterwards as a means of creating a vacuum in cylinders. (See Trans. vol. XIX, p. 483.)

to be constructed. I might say as much of that of the Marquis of Worcester.* Papin's machine, in which the action of steam and its condensation came successively in play, was only executed on a small scale, and only with the view of establishing experimentally the accuracy of the principle upon which it is founded.t

Moreover, although, properly speaking, there may be nothing very new in Savery's steam engines, they could not without great injustice be passed over since they are really the first which were probably in operation. Moreover, I do not think it necessary here to give a drawing of them: the reader can, without this assistance, form an exact idea of them if he will recall to mind that of Solomon de Caus and pay some attention to the following considerations. According to de Caus' plan, the steam which was to give the power would be generated in the vessel which contained the water to be raised, and at the expense of this same water. In Savery's machine, there are two separate vessels; one contains the water, the other, which might be called the boiler, contains the steam. This steam, when it is thought to be sufficient in quantity, is admitted into the upper part of the vessel of water through a communicating tube which is opened at pleasure by the aid of a cock. It acts downwards upon the surface of the liquid and drives it into a vertical tube, the lower opening of which ought to be always situated below this surface, otherwise the steam would escape through it. Up to this point the difference between the two machines is insignificant; let us continue the comparison.

sure.

In the machine of Solomon de Caus, as soon as the pressure of the steam has produced its effect, a workman replaces the expelled water by means of an crifice situated in the upper part of the metallic sphere, and which can be opened or closed at pleasure. Nothing more remains to be done then but to increase the fire. In Savery's machine, the vessel which is to contain the liquid is not supplied by a workman, but by means of atmospheric presThe steam driving before it, during the first period of its action, the water which the vessel contained, takes its place; now, the steam, whatever may be its original elastic power, must be condensed, in a great measure, if its temperature be much lowered. It is sufficient for this purpose, and such in fact is the process adopted by Savery, to throw cold water upon the sides of the vessel, containing it. After this operation, the atmospheric pressure easily surmounts the barely perceptible elasticity which the cooling has not annihilated, and if the vessel communicates by a

*The privilege solicited by the Marquis of Worcester was granted him according to Walpole, upon the simple assurance which he gave the commissioners named for this purpose, that he had invented a machine operating by the action of steam. If the machine had been really constructed, the remark relative to the declaration, as Mr. Stuart observes, had not been necessary. I am not ignorant that ultimately, it has been pretended, on the contrary, that the bill solicited by Worcester was the object of a long and minute examination, but to annul the evidence of Walpole it would have been necessary to prove that the commissioners appointed by Parliament had seen a machine in operation, or at least a model, and so far nobody has pretended this to be the case.

+ The Count of Sinzendorff, owner of several inundated mines in Bohemia, wanted Papin to go and drain them with his machine; but the unfortunate circumstances in which Germany was placed at that time prevented him from removing. "I should desire extremely, said he, to render my humble services to your excellency, were it not that the ruined state of the country in our neighbourhood, and the uncertainty of the events of the war, warn me that I ought not to leave my family at such a distance, and at a time like this." (Recueil de diverses pièces, etc., p. 49.)

tube, with a sheet of water, the level of which is not more than from 25 to 30 feet below, it will fill itself by suction. In adding that, to avoid intermissions in the supply of water, Savery employed a third vessel, which filled with liquid, while the second was emptying, and reciprocally, that the second and third vessel were, one after the other, in communication with the boiler, by the assistance of a convenient system of tubes and cocks, I shall have noticed every thing essential in this engineer's machine.

Solomon de Caus' apparatus has been found fault with, for only raising the water while hot. This reproach, it must be admitted, has some weight, in reference to economy, but it applies also, to a certain point, to Savery's engine. In this machine in fact, the steam proceeding from the boiler before acting upon the surface of the water of the second, or the third, vessel, is condensed in considerable quantities. Its elasticity does not becomeefficacious until after the water has acquired a high temperature: therefore when the water begins to rise, it is hot.* Robison said he had ascertained experimentally, that in employing steam as Savery did, at least 11ths is condensed, either by the sides of the second, or third, vessel, or by the water which they contain; even when the pressure is small. In an analogous machine, to avoid the enormous waste of steam, of which I have just spoken, Papin thought of interposing a piston or float, (flotteur.) This contrivance was not adopted, less, I think, on account of the difficulties in executing it, than on account of very serious defects inseparable from this kind of machine. To raise water to the inconsiderable height of 65 metres, (200 feet;) for example, Savery was obliged to raise the steam of his boiler to six atmospheres; hence, the continual derangements of the joints, hence, also, the melting of the cement, and even dangerous explosions. Moreover, in spite of the title of his work, the machines of this engineer served no useful purpose in the mines. They were only used to distribute water through various parts of the palaces, or of country seats, in parks or in gardens, wherever, in a word, the difference of level to surmount did not exceed some forty feet. With the assistance of the machine proposed by Papin, there is no height, on the contrary, to which water might not be carried, even in using a very low pressure of steam: for this purpose it is only necessary to give a sufficiently large diameter to the cylinder.

To sum up, Savery tried to make use of the elastic power of steam, to In fact, merely a thin stratum of hot water is formed by the condensation of the steam, and Savery's engine by no means raises hot water, as asserted by M. Arago; a very similar engine to Savery's, has recently been put up in one of the slaughter houses (abattoirs) of Paris to raise water! TRANS.

† Mr. Robert Stuart believes that in introducing a float in the body of the cylinder, Papin's object was not to hinder the condensation of steam. (Seea Descriptive history, 21 edit. p. 52.) Papin nevertheless explains himself very clearly upon this subject, and we shall even see by the passage, which I find in page 26, of the work published in 1707, how forcibly this defect struck him:

"I remark that the steam which passes into the pump to drive the water out of it, meets in the machine, (Savery's) cold water which condenses it, and makes it lose the greater part of its force. . . . . It is only after the water is heated that we can expel it....; to heat the water in this way a great deal of steam must be consumed. It is necessary, therefore, frequently to replenish the boiler with fresh water, and it requires a great deal of time, and of wood to heat it again. Lut by means of our piston, (flotteur a deux fonds) the steam encounters always the same surface of metal, which soon acquires such great heat that the steam loses little or nothing of its force by the contact."

drive up water in a vertical tube; but Solomon de Caus had done it precisely in the same way, eighty-three years before. Savery filled the vessels in which the steam was afterwards to operate, by suction; but suction was not a new principle in 1698, since the" abhorrence of a vacuum" had been very anciently invented to explain it, and because we find elsewhere applications entirely similar to those of the English machinist, in the Raisons des forces mouvantes; suction at the most, added very little to the value of the machine, for it increased only by some thirty feet the height to which the liquid would have been raised without its aid. Savery, at length, caused the vacuum which produced the suction, by condensing the steam; here the method is important, but Papin had published it long before. The patent granted to Savery is dated 25th July, 1698; the trials of his machine before the Royal Society, took place in the month of June, 1699; the first edition of the Miner's Friend is dated in 1702, thus Papin's titles have a priority of three years, even if setting aside the Acts of Leipsic, we only go as far back as the Recueil, in which several memoirs of this machinist are found, for this work was published in 1695. What then is left to Savery? The honor of having first executed on rather a large scale, a steam draining machine, and if you please, that of having caused condensation by the affusion of cold water on the outside of the metallic vessel containing the steam. In describing for the first time this ingenious method of producing a vacuum, Papin, in fact, neglected to explain the different constructions easy to imagine, (these are his expressions) which may be employed to attain this end. During his experiments with a small cylinder, he contented himself, as we have seen with removing the fire.

1705. Newcomen, Cawley, and Savery.*

The draining machine known to artisans by the name of Newcomen's engine, or, the atmospheric engine, was the first which rendered any essential service to art. I will observe indeed, that in a great many places where coal is not dear, it is still in use, and that it has not been found profitable to replace it. This machine, finally, excepting some details in its construction, which I shall notice farther on, is none other than the machine proposed in 1690, and 1695, by Papin, and which he tried on a small scale. In both, we remark, in fact, a vertical metallic cylinder closed at the bottom, open at the top, and having a well adjusted piston intended to work through its whole length. In both, the ascending motion of the piston works by the effect of a counter-poise, when the steam can come freely into the lower part of the pump and fill it. In the English machine, as well as in Papin's, as soon as the piston reaches the end of its ascending course, the steam which has forced it there is condensed, and in this way a vacuum is made in the space through which it has just passed, and the atmosphere forces it then to descend. Papin announced that this condensation must be effected by cold; and it is by cold that Newcomen, Cawley, and Savery, also get rid of the steam which would counter-balance the atmospheric pressure. Among many different constructions which may

* Thomas Newcomen and John Cawley, both lived in the town of Dartmouth, in Devonshire. The first was an iron monger or a black smith, for he is mentioned as exercising both of these trades in the English biographies; the latter was a glazier. Newcomen was a man of some education, and was in correspondence with Hooke, Secretary to the Royal Society, and one of the most ingenious Savants of whoin England may boast. We are ignorant whether the two associates took an equal part in the various experiments which led to the construction of the first large atmospheric engine.

be imagined for this purpose, (this is the expression contained in the Recueil de pieces, p. 53,) the English machinists have adopted one, much preferable in a large machine, to that which Papin himself used in the experiments made with his little model. In the place of removing the fire as Papin did, Newcomen, Cawley, and Savery, caused an abundant quantity of cold water to flow into the annular space comprised between the outside of the cylinder and a second cylinder rather larger in size, which enveloped it. The cooling communicated itself in this way gradually to the whole thickness of the metal, and soon reached the steam itself.

Papin's machine, thus modified as to the mode of cooling the aqueous vapor, excited the attention of proprietors of mines in the highest degree, and appeared, from the beginning, to furnish an unhoped for solution of the problem of which the fruitless attempts of Savery had particularly shown the difficulty. Newcomen, and Cawley, solicited a patent. Savery objected that he was already in possession of an exclusive privilege with regard to the means of producing a vacuum by condensing the steam. To avoid all dispute, the patent was taken out in the name, and for the advantage of the three competitors, who in this way attributed to themselves, in the plan borrowed from Papin, the two first the idea of the steam engine with a piston, and the third that of condensation.* At the commencement of the 18th century, the art of constructing large and perfect cylinders, and the art of fitting to them movable pistons, which close them hermetically, had made very little progress. Thus, in the machine made in 1705, to prevent the steam from escaping through the interstices comprised between the surface of the cylinder and the piston the upper surface of this piston was continually covered by a layer of water which penetrated into, and filled all the hollows.

One day while a machine of this description was in operation under the eye of the constructors, they saw, with extreme surprise, the piston descend several times in succession much more rapidly than usual. This rapidity appeared the more strange to them, as the refrigeration produced by the current of cold water which descended along the outside surface of the body of the cylinder, had so far been rather slow in producing the condensation of the steam on the inside. Upon verifying the fact, it was proved that on this occasion, the phenomenon was attributable to an entirely different cause: the piston having accidentally a small hole in it, the cold water which covered it, passed into the inside of the cylinder itself, in a jet, across the stream, cooled it, and consequently condensed it faster.

From this period, atmospheric engines were provided with an opening like the mouth of a watering pot; from this proceeded a shower of cold water, which spread in the interior of the cylinder, and there condensed the steam at the moment in which the piston was about to descend. The exterior * In the arts, as in the sciences, the last comer is supposed to be acquainted with the labors of those who preceded him. All denial in this respect is without value. The publication of the memoirs written by Papin upon the atmospheric engine, being much anterior to the patents granted to Savery and Newcomen, I shall have no motive for investigating whether the English machine is, or is not a copy: according to rale, it is a copy since it is like Papin's machine, and because it followed it. But we know moreover, in this particular instance, that Newcomen was acquainted with the plans of our countryman! It results, in fact, from various notes found among Hooke's papers, that the Dartmouth artist had consulted this famous Savant before beginning his experiments, and then, in the confidence of intimacy it was really the French engine which he wanted to construct. (See Robison A System, &c. vol. 11, p. 58.)