prodigious exaggerations; as, for example, when discussing the subject of steam-boats, he hesitates not to call Papin their "inventor," and to describe the English and American nations as a couple of thieves, who have robbed his country of her glory, and then quarrelled about the spoil! We therefore turn with great satisfaction to the work of another French author, which gained a prize proposed by the Imperial Academy of St. Petersburg, and in which it is said, "It appears that one of those to whom we owe the first idea of "the steam-engine is Papin, a French physician, Professor of Experimental Philosophy at Marburg, and Fellow of the Royal Society of London; for, besides showing the power "of steam by the famous experiment of his digester, he proposes, in a little work printed in 1695, the construction of "a new pump, the pistons of which will be moved by the "steam of boiling water:" but it is added, with equal justice and modesty, "It was a great thing even to suggest this idea, "but it remained to realise and execute it in a simple and "convenient manner. The English are the first who have "succeeded in that."*

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Of the ingenuity of Papin's idea of forming a vacuum by the condensation of steam, as well as of the real worthlessness in practice of his contrivance for producing it, we have repeatedly, in former works, expressed our opinion ;—an opinion in which we have the pleasure of believing that the best informed and most impartial mechanicians of either country will concur. Papin undoubtedly appears to have been a person who displayed very considerable ingenuity on those matters of physical inquiry to which his attention was directed; and if, in the history of the steam-engine, justice was for a time measured out to his name and works with rather a sparing hand, we must confess that in later times that deficiency has been fully compensated.

In the meantime, both as an act of justice to the memory of the ci-devant Secretary to the Royal Society, and for the

Théorie des Machines mûes par la force de la Vapeur de l'Eau. Par M. de Maillard, Capitaine - Lieu

tenant au Corps Impérial et Royal' 'du Génie.' 1784; pp. 8-10.

convenient reference of our readers, we think it right to give a translation of the paper published by Papin' in the 'Acta Eruditorum Lipsia' for 1690, in which we have endeavoured to convey very literally the sense of the original; together with a fac-simile engraving on wood of the figure, with letters of reference, by which the paper in the Leipzig Transactions is accompanied. On this paper, Papin's claims to be considered one of the early inventors of the steam-engine, so eagerly urged by his countrymen, principally depend; and it is, at all events, an interesting record of very considerable ingenuity on his part. Thus all may have it in their power to judge for themselves how far, without justifying the extravagant conclusions which have sometimes been deduced from it, it warrants the praise which we think is due to its author.

"A NEW METHOD OF OBTAINING VERY GREAT MOVING "POWERS AT SMALL COST. BY DENYS PAPIN.*

"IN the machine for a new use of gunpowder, which is "described in the Acta Eruditorum' for the month of Sep"tember, 1688, the first desideratum was, that the gunpowder "fired in the bottom of the tube A A should fill the whole

cavity with flame, so that the air might be entirely expelled "from it, and the tube remain a perfect vacuum beneath the "piston B B. But there it was mentioned, that the desired "effect could not be sufficiently attained; but that, notwith

standing all the precautions there specified, there always "remained in the tube about a fifth part of the air usually "contained in it. Whence a twofold inconvenience arises: "viz. 1st, that in this way we lose half of the desired effect, "so that scarcely can 150 lbs. weight be raised to the height "of one foot, when otherwise 300 lbs. ought to have been raised, if the tube A A had been perfectly emptied; and 2ndly, that as the piston gradually descends, the force

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*Translated from the Acta Eru'ditorum Lipsia' for 1690, pp. 410-414. The paper is also reprinted in the original Latin, in the Origin

' and Progress of the Mechanical Inventions of James Watt,' 1854, vol. iii. pp. 139-154.

"which makes it descend is itself diminished, as was also "observed in the passage already referred to. Thus we "have to provide, by some contrivance, that, as the moving "force decreases, the resistance may in like manner de"crease, so that it may be overcome by the aforesaid moving "force until the end: just as in watches the unequal force "of the main-spring, which moves the whole machine, is "so regulated by art, that through the whole of its running "down it overcomes the resistance of the wheels with equal 66 ease. But it would be far more convenient if the moving "force were to remain always the same, from the beginning "to the end. Some attempts have, therefore, already been "made to ascertain how a perfect vacuum could be obtained 'by the help of gunpowder; for in this way, were there no "air to offer resistance beneath the piston, the whole column "of the atmosphere pressing upon the said piston would press "it with an equable force down to the bottom. But hitherto "such attempts have been in vain; and always, after the "flame of the gunpowder is extinguished, about a fifth part "of the air remains in the tube A A.

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"By another way, therefore, I endeavoured to attain the "same end; and, since it is a property of water that a small "quantity of it, converted into steam by the force of heat, "has an elastic force like that of the air, but, when cold supervenes, is again resolved into water, so that no trace "of the said elastic force remains; I felt confident that "machines might be constructed, wherein water, by means "of no very intense heat, and at small cost, might produce "that perfect vacuum which had failed to be obtained by "aid of gunpowder. But of the various constructions which " can be contrived for this purpose, the following seemed to 66 me to be the most suitable.

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"A A is a tube of uniform diameter throughout, close shut " at the bottom; BB is a piston fitted to the tube; DD a "handle fixed to the piston; EE an iron rod moveable “round an axis in F; G a spring, pressing the cross rod E E,

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so that the said rod must be forced into the groove H as "soon as the piston with the handle has arrived at such a

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"height as that the said groove H appears above the lid II; "L is a little hole in the piston, through which the air can escape from the bottom of the tube A A, when first the "piston is forced into it. The use of this instrument is as "follows:-A small quantity of water is poured into the tube "A A, to the depth of 3 or 4 lines; then the piston is in"serted, and forced down to the bottom, till a portion of the "water previously poured in comes through the hole L; then "the said hole is closed by the rod M M. Next the lid I I, pierced with the apertures requisite for that purpose, is put “on, and a moderate fire being applied, the tube A A soon grows warm, (being made of thin metal), and the water "within it, being turned into steam, exerts a pressure so "powerful as to overcome the weight of the atmosphere and "force up the piston B B, till the groove H of the handle "DD appears above the lid I I, and the rod EE is forced, "with some noise, into the said groove by the spring G. "Then forthwith the fire is to be removed, and the steam in "the thin metal tube is soon resolved into water, and leaves "the tube entirely void of air. Next, the rod EE being "turned round so far as to come out of the groove H, and "allow the handle D D to descend, the piston B B is forth" with pressed down by the whole weight of the atmosphere, " and causes the intended movement; which is of an energy "great in proportion to the size of the tube. Nor is it to be " doubted that the whole weight of the atmosphere exerts its "force in tubes so constructed; for I have established by experiment, that a piston, raised to the top of the tube by "the force of heat, shortly afterwards descends again to the "bottom, and so on alternately for a number of times, so "that no suspicion can arise of air pressing beneath. Now "my tube, the diameter of which does not exceed 24 inches, "yet raises sixty lbs. aloft with the same velocity as the "piston is forced down into the tube, and the tube itself "scarcely weighs five ounces.

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"I therefore have little doubt but that tubes may be manu"factured, the weight of each of which would scarcely amount "to 40 lbs., and yet which could raise, at each operation,"