graph upon which the pretensions of Morland as a contributor to the creation of the steam engine are founded in England:

"Water being evaporated by the action of fire the steam thus produced requires immediately nearly 2000 times greater space than the water occupied before, and sooner than remain confined would burst a piece of ordnance. When subjected, however, to the laws of statics and reduced by science to measure, weight and equipoise, then it will bear its burden like a good horse, and will thus become of great use to the human race, particularly in the raising of water, according to the following table which marks the number of pounds which may be lifted 1800 times an hour at six inches of lift, by cylinders half filled with water, as well as the diameters and depths of the said cylinder."

If Morland's work had preceded those of Solomon de Caus or of Worcester, the passage which I have just read would constitute a true claim. In 1683, that is to say, sixty-eight years after the publication of Raisons des Forces mouvantes, and twenty years after the date of Worcester's patent, Morland's plan could be only considered as a plagiarism. Be it said, however, to the honour of this mechanician, that the numbers which he gives to express the relative bulk of water and of an equal weight of steam, come nearer to the truth than might have been expected from experiments made in 1682.

E

C

Fig.1.

P

B A

F

1690 and 1695. Denis Papin.*

Fig. 2.

P

B

D

Let us imagine a large vertical cylinder A, B, C, D, fig. 1, entirely open on the upper part, and resting upon a metallic base, furnished with a valve capable of opening from below upwards at pleasure. Let us place a movable piston P in the middle of the cylinder closing its opening very exactly. The atmosphere will press with all its weight upon the upper surface of this piston, and will force it from above downwards. If the valve S, is open, that portion of air with which the space D, C, E, F, is filled, will tend, on the contrary, by its reaction to raise the piston again. This second force will be equal to the first, because in a gas, as well as in a fluid, the

various motive powers which the mechanician brings into play, mentions the force of gunpowder and that of steam, without making any remark on this subject, by which we may infer whether he sets himself up as an inventor, or speaks of a thing already proposed by others.

*Denis Papin was born at Blois. In his youth he devoted himself to medicine and took his degrees in Paris; afterwards he crossed over to England where Boyle, who had associated him with some of his experiments, caused him to be nominated a member of the Royal Society in 1681. Being obliged to expatriate himself by the revocation of the edict of Nantes, Papin took refuge in Germany, under the protection of the Landgrave of Hesse, and filled with distinction for many years, the situation of Professor of Mathematics in the university of Marburg; he died in 1710. It must be considered as singular that the academy of sciences at Paris should not have named Papin one of their associates, when we reflect that in 1690 he published a memoir in which is found, as we shall see directly, the most methodical and the clearest description of the steam engine known at present under the name of the Atmospheric Engine, and even of that of steam vessels. A man of genius, no matter in what line, is always despised when he is in advance of the age in which he lives.

pressure in each point is the same in all directions. The piston thus acted upon by two opposing forces, which balance each other, will, nevertheless, descend, but only by its own weight. Any effort then, however small, if superior to this same weight will be sufficient to raise the piston to the top of the cylinder and keep it there. Let us suppose that in fact the piston is thus brought to the end of its course, as it is represented in fig. 2, and let us try to make it descend. A very efficacious way would consist in shutting the valve S, and afterwards, if it were possible, to annihilate suddenly and entirely in the cylinder that portion of air which occupies the space A, B, C, D. Then the piston would only be subject to the action of the outer air by which it is pressed. This impulse would be exercised on its upper surface, from above, downwards, and would be in measure, equal to a cylinder of water of thirty-three feet in height, the base of which would be equal to that of the piston, or, which amounts to the same thing, to the weight of a cylinder of mercury of a similar base, and thirty inches only in height; for such is the weight of the atmosphere. The piston would then descend necessarily, and could even drag with it a weight equal to that of the cylinder of water or of mercury of which I have just spoken. Following still the same hypothesis, let us admit that at the instant in which the descending movement is completely accomplished, the valve S is opened. The air will operate from below and will counterbalance the action of the air above. A trifling impulse will then suffice to force the piston back to the top of the cylinder and to bring back every part of the apparatus to its first position. A second exhaustion of the inner air would cause the piston to descend again, and so on in succession.

To recapitulate:-in this apparatus, a small expenditure of power is sufficient to raise the piston, whilst its descending motion is capable of producing a considerable effect. If a cord is attached by one end to the centre of the piston, and the other end is passed over a pulley, we may at each descending motion raise a very great weight, equal in amount to the height of the cylinder. With a cylinder one hundred square inches in area the weight raised at each descending stroke of the piston, would be 1500 pounds.

The idea of the machine of which I have just spoken belongs to Papin. It is very clearly explained in the Acts of Leipsic, for the year 1688, p. 644, and subsequently with some new developments in a letter to Count William Maurice. (See the work printed in Cassel, in 1695, and entitled: Recueil de diverses pièces touchant quelques nouvelles machines, p. 38 et seq.) It now remains for us to make known the means by which Papia proposed to exhaust, at the proper moment, the atmospheric air which, collected under the piston, would hinder its descending motion, or, what amounts to the same, it remains for us to explain how he made, at pleasure, a vacuum in the lower part of the cylinder.

This philosopher thought for some time of employing for that purpose a hydraulic wheel which would have set the piston of a common suction pump in motion. When the water course employed to set this wheel in motion should be too far from the machine, he proposed to connect it with the pump by the intervention of a continuous tube, like the gas pipes of our days: this was, he said, a means of transporting water power from a distance. [Un moyen de transporter fort loin la force des rivières.]

In this state, in 1687, the machine was presented to the Royal Society of London, where it gave rise to some difficulties which Papin mentions, without saying, however, in what they consisted. (See Recueil, p. 41.) He VOL. XXV-No. 1.-JANUARY, 1840.

2

had tried previously to make the vacuum under the piston by means of powder; but "notwithstanding all the precautions which have been observed," says he, "there has always remained in the tube about a fifth part of the air which it usually contains, which causes two different inconveniences. One is, that half the power which we ought to obtain is lost, so that we could only raise one hundred and fifty pounds to every foot in height, in place of three hundred pounds which ought to be raised if the tube had been perfectly emptied; the other inconvenience is that in proportion as the piston descends, the power which pushes it down diminishes more and more, etc. (Recueil, etc., p. 52.)

"I tried then, he adds, to succeed in another way; and as water being changed by fire has the property of becoming elastic as air, and afterwards of recondensing itself so completely BY COLD that it retains no appearance of this elastic power, I have thought that it would not be difficult to construct machines in which, by the means of a moderate heat and at little expense, water would create this perfect vacuum which has been fruitlessly attempted by the means of gunpowder,"

This important paragraph is found in the 53rd page of the collection, printed at Cassel in 1695, as extracted from the Acts of Leipsic, of the month of August 1690. It is followed by the description of the little apparatus which Papin made use of to try his invention. The body of the cylinder was only two and a half inches in diameter and weighed but five ounces. At every vibration it raised sixty pounds, however, a distance equal to that of the descending stroke of the piston.

When the fire was removed, the steam disappeared so completely that the piston to which it had given the ascending motion "redescended to the very bottom, so that it could not be suspected that any air remained to act on it from below and resist its descent." (Recueil, p. 55.)

The water which furnished the steam in these first experiments, was not contained in a separate boiler, it was contained in the body of the cylinder itself, resting upon the metallic plate which closed it below. Papin heated this. plate directly to convert the water into steam; and cooled it by removing it from the fire when he wished the steam to condense. He relates that with a moderate fire, a minute was long enough, in the experiments of 1690," to drive the piston in this way to the very top of its tube." (Recueil, p. 55.) But in the experiments which he afterwards made he emptied the tube in a quarter of a minute.

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Moreover, he himself declares that setting out from the principle of the condensation of steam by cold, the end proposed may be attained ferent constructions easy to imagine." (See the Recueil, p. 53.) The machine of Solomon de Caus and that of the Marquis of Worcester were intended for draining. Such also was the principal use which Papin expected to derive from his atmospheric pressure engine; but at the same time he saw perfectly that the reciprocating motion of the piston in the cylinder was capable of other applications and might become an universal motor. We find, in fact, in page 58 and 59 of the Recueil, and even before it in the Acts of Leipsic of 1690, a plan for converting this alternate movement into one of rotation. I will not dwell longer here upon this subject since we shall have to resume it further on in treating of steam vessels, and I will finish with Papin by presenting to the reader the various consequences which appear to me to flow from the extracts which we have just read.

Papin conceived the first steam engine with a piston.

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.

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.)