CHAPTER XII.

THOMAS SAVERY- THE MINER'S FRIEND -DESCRIPTION OF HIS STEAM-ENGINEUSES TO WHICH IT COULD BE APPLIED-PAPIN'S INFERIOR IMITATION OF IT ESTIMATE BY HORSE-POWER—SIR SAMUEL MORELAND-NEWCOMEN AND CAWLEY THEIR GREAT IMPROVEMENTS—DESAGULIERS-AMONTONS AND DALESME—SMEATON.

In the contrivance which has thus made the name of Papin, to say the least, quite as famous as it deserves, the vessel in which the steam was tediously generated, and then allowed slowly to condense, was at once boiler and cylinder; and, so long as it continued to fulfil alternately the functions of both of those vessels, it was necessarily unfit to do any really effective work. In order to the accomplishment of that desideratum, it was essential that the steam should, on the one hand, be steadily, continuously, and abundantly produced, and, on the other, that it should from time to time be condensed with at least tolerable rapidity. The honour of making this great step in advance,-the first that in fact led to the attainment of any really useful results from the employment of steam as a motive power of machinery, and which, therefore, it seems impossible too highly to commend,-belongs entirely to an Englishman, Captain Thomas Savery. Of his life and private history but little appears to be known.

But of his steam-engine Savery has luckily left us a very particular description, in a work entitled 'The Miner's Friend, or an Engine to raise Water by Fire described, and the Manner of fixing it in Mines, with an Account of the several other uses it is applicable unto; and an Answer to the objections made against it. By Tho. Savery, Gent. Pigri est ingenii contentum esse his

quae ab aliis inventa sunt. Seneca. London, printed by S. Crouch at the corner of Pope's-head Alley in Cornhill. 1702.' The edition from which we copy this title is of that date; but Mr. Robert Stuart, at p. 34 of his History of the Steam-engine,' published in 1824, says, quoting from Robison, "The fact is, Savery obtained his patent in 1698, after hearing of objections;

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but, besides this, he had erected several of his engines before he obtained his patent;" "and," continues Mr. Stuart, "published an account of his engine in 1696, under the title of The Miner's Friend, and a Dialogue by way of answer to the objections which had been made against it, in 1699. What is most important is, that the letter-press of 'The Miner's Friend' is accompanied by a very clear and sufficiently well-executed engraving, including two figures, each of about twelve inches in height, of which the first represents "The Engine for raising Water by Fire," and the second represents the same engine "working in a mine." In the former, the various parts are all delineated on such a scale, that, with the aid of the particular description accompanying it, it is impossible to mistake either their proportion or their mode of action; and of both figures it may with perfect confidence be asserted that they are the first representations to be met with in the publications of any country, of a real steam-engine doing useful work.

Savery's engine, as so described and delineated, acted by two distinct principles; raising water, in the first place, by the pressure of the atmosphere forcing it into a vacuum formed by the condensation of steam; and, in the second, by the expansive power of steam. The steam from the detached boiler was let into a vessel called a receiver, and, having driven out the air, was condensed by the effusion of cold water, and a partial vacuum formed. A communication being then opened with a suction-pipe, twentyfour feet in height, the lower end of which was placed in a cistern or reservoir of water, that water was forced upwards, by the pressure of the atmosphere, into the receiver. When this was nearly filled, the communication with the suction-pipe was shut off, the

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steam was readmitted into the receiver, and by its expansive power forced the water contained in it up an ascending, or, as he called it, a force-pump. This second operation is similar to one of those experimentally tried by Porta, and indicated by Solomon de Caus; and not only indicated, but perhaps practised, by the Marquis of Worcester. The prior operation,-that of raising the water into a vacuum formed by the condensation of steam, believe to have been original with Savery. For, although both Portia and Papin had described the principle, they applied it in a different manner; and there is no proof, or even surmise, of its having been known to Savery when he invented his engine in 1696, or perhaps sooner. Indeed, Papin, with praiseworthy candour, as quoted by Belidor, ('Arch. Hyd.,' tome ii. p. 309,) writes, “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."

Switzer, in his 'System of Hydrostatics and Hydraulics,' published in 1729, says, p. 325, "Among the several engines which have been contrived for the raising of water for the supply of houses and gardens, none has been more justly surprising than that for the raising of water by fire, the particular contrivance and sole invention of a gentleman with whom I had the honour long since to be well acquainted; I mean the ingenious Captain Savery, some time since deceased, but then a most noted engineer, and one of the Commissioners of the sick and wounded.

"It was a considerable time before this curious person, who has been so great an honour to his country, could (as he himself tells us) bring this his design to perfection, on account of the awkwardness of the workmen who were necessarily to be employed in the affair; but at last he conquered all difficulties, and procured a recommendation of it from the Royal Society, in Trans. No. 252, and soon after a patent from the Crown, for the sole making this engine. And I have heard him say myself, that

the very first time he played it, was in a potter's house at Lambeth, where, though it was a small engine, it forced its way through the roof.”

Savery, in the second chapter of his 'Miner's Friend,' entitled "Of the uses that this Engine may be applied unto," enumerates-1. The working of mills, by raising water, afterwards to be employed in a steady stream turning water-wheels; 2. The supplying palaces, or noblemen's and gentlemen's houses, with cisternfulls of water, for domestic use throughout the house, for fountains, or in case of fire; 3. The serving cities and towns with water; 4. The draining of fens and marshes; 5. "I believe,” he says, "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 maritain affairs;" 6. The draining of mines and coal-pits: all of which purposes may, he considers, be answered at far less cost by using his engine than by employing horse-power. And with regard to the last, he suggests that in very deep mines there might be a succession of steam-engines placed at various depths in galleries leading from the shafts.

We have already incidentally referred to Papin having, on the appearance of Savery's invention, abandoned his own idea of 1690, and proceeded to make a steam-engine on other principles, with several variations from that of Savery in the construction of the parts. Belidor, quoting from the work of Papin in 1707, says that "from the year 1698," (the date, it will be observed, at which Savery is said to have obtained his patent, and two years subsequent to the first publication of the description of his engine in the first edition of The Miner's Friend,' in 1696,) "he had made a number of experiments by desire of the Landgrave Charles of Hesse Cassel, to raise water by fire, which he had communicated to divers persons, and among others to Leibnitz, who answered that he also had entertained the same idea.

"This work having been interrupted," continues Papin, "would perhaps have been forgotten, had not Leibnitz, in a letter

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of 6th January, 1705, done me the honour to ask my opinion of the machine of Mr. Thomas Savery, of which he sent me the print made in London. Although its construction was a little different from ours, and I had not the description sent me, I saw at once that the English machine and that of Cassel were founded upon the same principle, as I showed to the Landgrave; which caused his Highness to resume the design of pushing on this invention, which, without doubt, is a very useful one, as will be seen hereafter. I can then testify that it has cost much time, labour, and expense, to bring it to its present state of perfection. It would be tedious to particularize all the unforeseen difficulties met with, and all the trials which have turned out contrary to expectation; and, therefore, I shall limit myself to making known how far what we now have is preferable to what we had done at first, and to what Mr. Savery has since done, that the public may not be under any mistake in the choice of these different machines, and may profit, without trouble, by what has proved so expensive; and likewise that they may see that their obligation to his Highness is not solely for having formed the first plan, but for having overcome the difficulties of the first execution, and brought matters to their present state of perfection.”

Belidor, after this long quotation, goes on to observe-"M. Papin then gives the description of the machine he had executed, and forgets nothing to give it value. But, whatever he may say, it is very far from being equally ingenious and complete with that of Mr. Savery, which possesses the advantage of having within itself all the movements it requires, without any one touching it; whereas the other cannot act without the help of several men, one of whom at least is required to give his work uninterruptedly, with contrivances which render this machine as imperfect as that of Mr. Savery is complete. It does not, in fact, appear that the engine improved by Papin, after he was made acquainted with Savery's engine, was ever brought into practical use.

It deserves also to be mentioned that Savery, with the same attention to practical utility by which all of his mechanical pro