A DIALOGUE
BETWEEN A MINER AND THE AUTHOR.
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Miner . Sir, having been some time concerned in the engines now used for drawing water out of our mines, and hearing so much talk of this wonderful invention of yours, of raising water by fire, I was very desirous to enter into some discourse with you concerning the nature, use, and application of your engine, so strangely differing from all other engines ever yet invented for our works, and which, you positively affirm, will every way tend so much to our advantage in the use of them; and I do not doubt of meeting with that plainness, freedom, and good humour, that your discourse is generally accompanied with. And with the same freedom resolve me in such questions as the general sense of us miners may naturally propose to object against the use of your engine, especially such of us as are yet ignorant of its use and operation, who are more capable to judge of fact, than of the nature and power of that force which raises your water.
Author . Sir, I am extremely obliged to you for your freedom, and shall readily embrace all opportunities to inform and explain to you the true use and nature of my engine; and, therefore, desire you, with all imaginable freedom, to proceed and ask what questions you please, either as to your own thoughts, as well as what has been suggested to you by others. And you may be assured of a plain and candid answer to all your objections.
Miner . Then, sir, which way will you go to work with your engine to clear an old work full of water?
Author . Why, sir, to deal plainly with you, if your shafts are, or may be cut straight, your tub-engines, or chain pumps, may draw forth the water. And the charge, in that respect, is not to be accounted for, because no mine would be thrown up or neglected but on account of the feeders or springs, which being certain, and constantly to be carried off winter and summer, the prospect of being likely to succeed, makes your mine worth working or emptying within twenty feet of the bottom, if ever they were worth sinking, though you work or drain by the common way of tubs or chain-pumps. And could the constant charge of those engines be afforded, numbers of them will empty and keep under any work; but it is the constant charge of carrying off what the springs bring in is the chief thing to be considered in the business of mines, which constant charge is what we lessen very much by this engine of mine.
Miner . What signifies your engine then, sir, if it be not capable of sinking or forking an old mine?
Author . Hold, my good friend, a little patience; I have dealt plainly and impartially with you about the use of your old engines: and for my engine, it will clear an old work, if full of water, as readily as your tub-gins or chain-pumps, provided the shafts are good. The method I propose to clear an old mine, if sixty feet deep, and full of water, the feeders not above two-inch bore, which is done at a very small charge after this manner; viz. I fix my engine on the top of the mine, and only suck and deliver a three and a quarter inch bore; as soon as we have sunk the water as far as our suction will go, which will be some twenty-two, twenty-four, or twenty-six feet deep below the surface, there I make a room fit to receive another engine, which I fix with his force-pipe to go up to the top of the pit; and when I have sunk about twenty-four or twenty-six feet more, then I fix a smaller engine of two inches bore, which, sucking twenty, and forcing forty, does your work and keeps all safe; or let your small engine be kept at work, while you remove the larger engine from the top to the middle station, and then you will have occasion for no more than two engines, the greatest of which may be removed as soon as the smaller is fixed in the lowest or proper station. And that you may be convinced of my impartiality, it is my opinion, that in gaining an old work, or sinking a new one, you use your old engines of tub or chain-pumps: this engine of mine being most proper, when you are come fairly to the bottom either of the ore or coal; for then, if you have but one lift, one station or engine-room will be sufficient. And by having two sumps or bottom cisterns, your water may, in some measure, settle in one of them in its passage to the other. So that the miners working tolerably clean, and suffering as little dead or loose coal or ore as is possible to mix with the water, you may have the water to draw only a little discoloured; for you know, as well as I, that generally the water coming from mines or coal-pits, while they work by the gins now in use, is almost clear water.
Miner . Sir, I thank you for your candour in relation to the clearing of an old work. But supposing that our water arises thick and muddy, which you know will sometimes happen, what shall we do with your engine then?
Author . What you say, sir, I know to be very true, that sometimes you have thick, muddy gravel and nasty water. To prevent which from coming into, or offending our pipes, we have a frame of board made full of holes round about the bottom of our pipe that receives the water, for sluge or fine dirt it will do my engine no injury. Indeed, the clearer our water is in our boilers the better it is for our work; but for our receivers and their clacks you may clear them as you work it from stones, coal, ore, or any other annoyance, though hung in the very clack; for by emptying of one or both the receivers of their water, you cause the motion, either of suction or force, immediately to be so strong, as to clear and blow out all before it to the top of the pit; insomuch, that I have found filings of copper, large bits of metal, considerable quantities of coal and stone, delivered and thrown up with water out of my engine above sixty feet high. However, clear water is preferable before the dirty water in the work of mine engine.
Miner . But, dear sir, if sixty, seventy, or eighty feet be the determinate height for raising of water by your engine, how shall we use your engine in a mine or pit that requires water to be raised three times eighty feet, as you know some of our works do.
Author . I heartily thank you, sir, for this last proposal, because I have now an opportunity to acquaint you, that the force used in my engine is in a manner infinite and unlimited, and will raise your water five hundred or one thousand feet high, were any pit so deep; and that you could find us a way to procure strength enough to support such an immense weight, as a pillar of water a thousand feet high must certainly produce. However, to give you an answer, I must entreat you to give my engine as kind entertainment and fair quarter as you do to your engines now in use: for, I am sure, you are not ignorant of a custom used in very deep mines, (in several parts of England,) of raising their water by several lifts, from cistern to cistern, to a very great height, although some of their lifts may not be above twelve, sixteen, or twenty feet a lift at the most. And suppose that your engine now in use at twenty feet the lift, and my engine at sixty, seventy, or eighty feet, for at any of these lifts we raise a full bore of water with much ease, then one lift of my engine at sixty feet answers to three lifts of your engines at twenty feet, and also to four of your lifts at eighty feet, &c., which you may please to take for a sufficient answer to your last objection. I have known, in Cornwall, a work with three lifts, of about eighteen feet each lift, and carrying a three and a quarter inch bore, that cost forty-two shillings per diem, reckoning twenty-four hours the day, for labour, besides wear and tear of engines; each pump having four men working eight hours, at fourteenpence a man, and the men obliged to rest at least one-third part of that time.
Miner . You have, sir, hitherto given me undeniable answers to my former objections, for which I thank you; but I fancy I shall puzzle you, when I ask you how you will manage your engine to draw up our water, where the shafts are not direct, but turn and wind to and fro?
Author . Sir, this last question is so far from being any hardship put upon my engine, that no engine ever yet invented was so naturally adapted to work in these crooked shafts as mine is; for let the windings or turnings of the shafts be what they will, the perpendicular weight of water is all that my engine has to account for, and is the same as if it made the figure of a distiller’s worm, and went through the straightest pipe imaginable, except a little inconsiderable friction of the water against the side of the pipe that is crooked, more than is in the straight pipe, which is so small a matter, that a very nice judge would hardly be able to distinguish whether the crooked or straight pipe carried off most water in the working. For the flue that carries the smoke, experience sufficiently instructs you, that you may turn and wind it any way you please, and that such windings in their drawing most air do rather improve than prejudice your flue, as any one experienced in building of furnaces can inform you.
Miner . Well, sir, I find that our crooked shafts will not any way incommode your engine: but what think you of accommodating your engine to the service of the lead mines, whose shafts are many times so narrow, that it will be very difficult to get your engine down?
Author . I perceive, sir, you are yet much a stranger to the nature of my engine, which is so furnished with brass screws, and as strong as the very metal itself, that you may take it to pieces, and with ease put it together again fit to work in a few hours’ time; and so contrived, that where a man can well go down, there I can put down my engine in several pieces and fix them below, for the greatest boiler belonging to my engine is between twenty-four and thirty inches diameter, and may, if occasion require, be made yet much narrower and deeper. And that if it be difficult to bring the shaft of the mine to fit my engine, I can, with much ease, make my engine to fit the shaft of any mine.
Miner . But will not these brass valves that you speak of in your engine, speedily wear out and stop your work?
Author . No: they cannot fail me; because experience shows us, that brass valves improve, rather than grow worse, by twenty or thirty years use in any force-work, where constantly worked, and where they rise and fall twenty times oftener than my valves will do.
Miner . But what think you, sir, if you should meet with such corrosive water in some of our mines, as will, in a little time, eat through your copper vessels.
Author . Truly, sir, this question does a little startle me, because I never expected to meet any water of such a corrosive quality in any mine: and could I find out a mine, whose water abounds with such acid particles, as to destroy or injure the copper vessels of my engine, I would drain that mine for nothing but the water I shall take up; because the water would be more valuable than any ore (I believe) in England. And were there even a tenth part of aquafortis to nine-tenths of common water, which is impossible to suppose it should be, I say, such a water could have no effect on the coppers, were that water to lodge some time in the copper vessels, much less in passing through them with that celerity and rapid motion that always accompanies it.
Miner . But, sir, will not such a continual fire, as must be kept under your boilers, burn them out in two or three months’ time, and spoil the work of your engine?
Author . I can assure you they will not decay in some years, unless some fellow be hired or employed on purpose to do it. And should any villain be employed to burn, break, or destroy any of the engines now used in your works for raising of water, we are then on the same level with you in that point. But I will give you one reason why my engines will not easily decay, and I am sure that will go further with you than all the affirmation I can make. For, first of all, although a white heat will melt copper, and a red heat, and sudden cooling it again, will scale the copper, yet such a heat as is possible for it to have or suffer while water is in the boiler can have no ill effect, or cause any alteration in our copper. A friend of mine has coppers used in sugar boiling of twenty years’ standing. They may be a small matter worn with cleaning on the inside, whereas on the outside there does not appear the least visible decay: for as soon as the fire has thrown a thin coat of soot on the outside of the boiler, the flame has no other effect on it than to cause the water in it to boil.
Miner . But we have often combustible vapours in our mines, which taking fire from the candles used there, do, by a sudden explosion, destroy both the mine and the miner; and therefore I am afraid that the fire used in your engine will be very dangerous, and apt to kindle those combustibles more than our candles.
Author . To answer this objection, I will desire leave to give you my notion of those combustibles, which, in short, is this: that when your miners come into a close place, where there is no circulation of air to carry off the effluvia, or atoms constantly rising like fine dust in a powder-mill, they by knocking and working do increase to be very numerous, like to those loose particles in a powder-mill. But it is the work of some time for those vapours to come to perfection; for I have heard several experienced miners say, that it is common to avoid the danger of those vapours, by retiring as soon as they see the flame of their candles burn longer than ordinary, which may be, discerned sometimes long before the air is thick enough of this combustible matter to take fire at once, and, like gunpowder, to destroy all. I did hear one say, that from an inch and a half, once the flame of his candle did gradually increase to two feet long, and yet he escaped. Which makes it very plain, that stagnation of air is the sole cause of this inconvenience in mines, which may be totally prevented by a pipe going from the ash-pit of our furnace to any part of the mine liable to stagnation. For the air will press with great violence through the pipe into the fire, before the combustible matter can be ready to do any hurt, and passing through the fire, make way for fresh air to descend in the room of it. So that our fire, instead of blowing up of your works, is the best means that can be used to prevent so fatal an accident; and will likewise carry off all unwholesome vapours, damps, or steams, which may proceed from corruption of air, by stagnations or vapours arising from any poisonous earth or mineral.
Miner . This notion of yours carries reason and demonstration along with it, which pleases me wonderfully. But, sir, is not your price too great for these engines of yours?
Author . By what I shall offer to you, as to my price, I am sure to have you a friend to me and my engine for ever. For I must tell you, that I would never have sent my engine into the world, if it would not raise your water with more ease and conveniency to you and your servants, and also much cheaper than any other engine ever used in your works, without which I could never propose any advantage to myself by it. And to convince you of the truth of my assertion, I dare undertake the engine shall raise you as much water for eightpence, as will cost you a shilling to raise the like with your old engines in coal-pits. By this one article the miner will save one-third part of his former charge, which is thirty-three pounds six shillings and eightpence saved out of every hundred pounds. A brave estate gained in one year out of such great works, where three, six, or it may be eight thousand pounds per annum is expended for clearing their mines of water only, besides the charge and repair of gins, engines, horses, &c. I hope you will not now account my engines dear under such conditions as I now offer; but if I should, with you, suppose my engine proportionably dear, or as dear as the engines you now use for drawing up your water, which is impossible, my engine will be preferable before yours in many respects, insomuch, as mine prevents your damps, and the evil effect of them: and as it will be my interest to allow those that first set my engine at work considerable advantages, so I hope I may assure myself of due encouragement from the ingenious, who are ever studious to promote all inventions useful and beneficial to the public; for they must conclude, that an engine which for some time has daily employed the best artificers to work on it, was not to be brought forth in one day: and to bring it to that perfection you now find it, must have cost me and my friends not a little money to make the workmen capable of their work with that certainty and exactness they now do. And for working the engine any person may have his servant taught it, it being to be learnt in a very short time by one of an ordinary capacity.
Miner . But there are people who pretend to do great things in the improvement of engines to work by hand or horses, the hope and expectation of which has hindered some of us in our work and tired others, so as to make them out of love with all engines, and almost with the trade of mining. And though I wish the contrary, I fear this may prove some hinderance to the promoting your interest.
Author . True, sir, I own that time out of mind there have been mountebanks and impostors in all faculties who pretend to great things, but do perform nothing effectually. And it would be hard if that should be drawn into consequence, that because some are knaves, therefore none are honest. I know the notions of the perpetual motion, or self-moving engine, and many such like whims are pretended to by designing men, and believed by ignorant ones: but the judicious man, who considers the laws of motion, knows it is an infallible rule, that whatsoever matter is to be removed upward, must have a force superior to the weight to be lifted up, if its motion be required as swift as the motion of the moving cause; if slower, proportionably less strength will do; if swifter, then the moving cause, as men’s hands, horses, or dead weight, then must the strength of the moving cause be increased proportionably, or no motion can be produced. And the experience of ages shows us this to be a most sure rule, allowing for friction, which is larger, the more wheels or parts an engine consisteth of; and, of consequence, the fewer parts or wheels an engine consisteth of the easier it works; so that by barely looking on a pump, if it has more parts or wheels than the common crank-work, you may conclude it worse; if a chain-work or tub-work the same. So that all that can be expected is, to make those go easier than they are now made to go by ingenious workmen expert in making them. And if you try how small a matter will move those engines when not loaded with water, you will find the friction so small as not worth any mending, could it be done, especially the tub-gin, whose friction increases the least in being loaded of any; but the others are vastly increased by the leathers of their suckers being forced broader, and rubbing with much greater force against the barrel they work in, according to the height the pipes are raised.
And I hope, when it is considered how far this engine of mine differs from the bare pretensions of ignorant or designing men, and that any persons may see what my engine will perform before they contract for it, there will be found no ground for the least suspicion in any person concerned to employ them in mines; but, to the contrary, afford us a generous encouragement in a business so conducive to the increasing the mining trade, and thereby enrich themselves and the nation, and increase the king’s revenue.
I could heartily wish all miners, for their own as well as their country’s interest, were good mechanics, and truly understood the nature, use, and application of all kinds of engines; for, I am sure, those that do will be my best friends, without expecting that horses, or men, or any other strength, can or will do more than what nature and the laws of motion has allowed them.
