Denis Papin

"I have endeavoured to attain this end (viz. the production of a vacuum in the cylinder) in another way. As water has the property of elasticity, when converted into steam by heat, and afterwards of being so completely recondensed by cold, that there does not remain the least appearance of this elasticity, I have thought that it would not be difficult to work machines in which, by means of a moderate heat and at a small cost, water might produce that perfect vacuum which has vainly been sought by means of gunpowder."

"Turning a small surface of water into vapour by fire, applied to the bottom of the cylinder that contains it; which vapour forces up the plug (or piston) in the cylinder to a considerable height, and which, as the vapour condenses, (as the water cools when taken from the fire,) descends again by air's pressure, and is applied to raise water out of the mine."

"What I say here is not to give room for believing, that Mr. Savery, who has since published this invention at London, is not actually the inventor. I do not doubt that the same thought may have occurred to him, as well as to others, without having learnt it elsewhere."

"In the machine for a new use of gunpowder, which is described in the 'Acta Eruditorum' for the month of September, 1688, the first desideratum was, that the gunpowder fired in the bottom of the tube AA 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 BB. But there it was mentioned, that the desired effect could not be sufficiently attained... 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 AA."

"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 me to be the most suitable."

"AA 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 EE, 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 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 AA, 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 AA; to the depth of 3 or 4 lines; then the piston is inserted, 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 MM. Next the lid II, pierced with the apertures requisite for that purpose, is put on, and a moderate fire being applied, the tube AA 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 BB, till the groove H of the handle DD appears above the lid II, 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 DD to descend, the piston BB is forthwith 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 2 ½ 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. I therefore have little doubt but that tubes may be manufactured, the weight of each of which would scarcely amount to 40 lbs., and yet which could raise, at each operation, two thousand lbs. to a height of four feet. ...If any one now will consider the magnitude of the forces to be obtained in this way, and the trifling expense at which a sufficient quantity of fuel can be procured, he will certainly admit that this my method is far preferable to the use of gunpowder above spoken of, especially as in this way a perfect vacuum is obtained, and so the inconveniences above recounted are avoided."

"In what manner that power can be applied to draw water or ore from mines, to discharge iron bullets to a great distance, to propel ships against the wind, and to a multitude of other similar purposes, it would be too long here to detail; but each individual, according to the particular occasion, must select the construction of machinery appropriate to his purpose."

"About the year 1761, or 1762, I tried some experiments on the force of steam in a Papin's digester, and formed a species of steam-engine by fixing upon it a syringe, one-third of an inch diameter, with a solid piston, and furnished also with a cock to admit the steam from the digester, or shut it off at pleasure, as well as to open a communication from the inside of the syringe to the open air, by which the steam contained in the syringe might escape..."

"Dr. Denys Papin, a native of Blois, a man of great ingenuity, and of considerable acquirements as a philosopher, is considered by his countrymen to be the true inventor of the Steam Engine: a claim strongly contested by some English authors of eminence who have written on the subject,—but on grounds which appear to have been taken from very erroneous and prejudiced statements. It is due to Papin, to state, that no one, whose labours have produced so many important results, has in his writings shewn so little of the vanity and absurd enthusiasm proverbially characteristic of an inventor."

"The first machine of Papin was very similar to the gunpowder-engine... of Huyghens. In place of gunpowder, a small quantity of water is placed at the bottom of the cylinder, A; a fire is built beneath it, "the bottom being made of very thin metal," and the steam formed soon raises the piston, B, to the top where a latch, E, engaging a notch in latch engaging the piston rod, H, holds it up until it is desired that it shall drop. The fire being removed, the steam condenses, and a vacuum is formed below the piston, and the latch, E, being disengaged, the piston is driven down by the superincumbent atmosphere and raises the weight which has been, meantime, attached to a rope... passing from the piston rod over pulleys... The machine had a cylinder two and a half inches in diameter, and raised 60 pounds once a minute; and Papin calculated that a machine of a little more than two feet diameter of cylinder and of four feet stroke would raise 8,000 pounds four feet per minute—i.e., that it would yield about one horse-power."

"In 1680, Robert Boyle published the Second Part of his Continuation of New Experiments Physico-mechanical, Touching the Spring and Weight of the Air. ...According to Boyle's preface, the experimental work... was mainly done by a remunerated technician... Denis Papin. The air-pump with which the experiments were performed was... of Papin's own design... At least some, and perhaps the greatest part, of the design of the experimental project was also owing to the technician. ...It seems also that the technician was partly, if not mainly, responsible for the composition of the experimental narratives."