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,wonderful invention of yours of raising Water by the Fire, I was very desirousto Enter into some Discourse with you, concerning the Nature, Use, and Application of your Engine, so strangely differing from all other Engines ever which you positively affirm will every way tend so much to our Advantagein the use of them; and I will not doubt of meeting with that plainness, Freedom, and good Humor, 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 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 foot of the bottom, if ever they were working sinking, though you work or Drains 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 foot 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 3 inch-bore; as soon as our suction will go, which will be some 22, 24, or 26 foot 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 about 24, or 26 foot more: Then I fix a smaller Engine of two inches-bore, which sucking twenty and forcing forty, does your and keep 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 Oar 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 concerns, your Water may in some measure settle in one of them, in its passage to the other. So that the miners working tolerable clean, and suffering as little dead or loose coal or Oar, as is possible, to mix with the water to draw only a little discolored; for you to 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 Candor in relation to the clearing of an Old Work. But supposing that our water arises thick and muddy, which you know will some times happen, what shall we do with your Engine then?
Author. What you say Sir, I know to be very true, that some times thick muddy gravel and nasty water. To prevent which from coming in to, 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; foe sluge or fine dirt, it will do my Engine no injury. Indeed the clearer our water is in our Boylers, 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, Oar, 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 the water out of my engine above sixty foot high. However, clear water is preferable before the dirty water in the work of mine engine.
Miner. But dear Sir, if 60,70, or 80 foot 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 80 foot, 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 I will raise your water 500 or 1000 foot high, were any pit so deep; and that you could find us a way to procure strength such an immense weight, as a pillar of water a thousand foot high must certainly produce. However, to give you an answer, I must in treat 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 foot a lift at most. And suppose that your engine now in use at twenty foot the lift, and my engine at sixty, seventy, or eighty foot, for at any of these lifts we raise a full bore of water with much ease, Then one lift of my Engine at sixty foot answers to three lifts of your engines at twenty foot, and also to four of your lifts at eighty foot, etc. which you may please to take for a sufficient answer to last your objection. I have known in Cornwall a work with three lifts, of about eighteen foot each lift, and carrying a 3 inch-bore , that cost forty two shillings per diem, reckoning twenty four hours the day, for labor, besides ware and tare of engines; each pump having four men working eight hours at fourteen pence a Man, and the men obliged to rest at least 1/3 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 distillers 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 nice fudge would hardly be able to distinguish, whether the crooked or straight pipe carried off most water in the working. For the flew that carries the smoak, 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 Flew, 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 it sells, that you may take it together again, fit to work in a few hours time; and si contrived, that where a Man can well go down my engine, in several pieces, and fix them below; for the greatest boyler belonging to my engine, is between twenty four and thirty inches Inches Diameter, and may, if occasion require, be made yet 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 ware out and top your work?
Author. No: They cannot fail me; because experience tells us, that brass valves improve, rather than grow worse, by twenty or thirty years. Life in any work force, where constantly worked, and where they rise and fall twenty times more often than my valves will do.
Miner. But what think you, Sir, if you should meet with such corrosive water in some of 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 a 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 oar (I believe) in England. And were there even a tenth part of the aquifer to the 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 celebrity 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 implied on purpose to do it and should any villain be implied 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 suddenly cooling it again, will scale the cooper, yet such heat as is possible for it have or suffer will 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 inside, whereas on the outside there does appear the least bit of 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 vapors 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 closed place, where there is no circulation of air to carry of the esluvia, 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 the powder mill. But it is the work of some time for those vapors to come to perfection; for I have heard several experienced miners say, that it is common to avoid the danger of those as they see the flame of their candles burn longer than ordinary; which may be the difference from times long before the air is thick enough of this combustible matter, to take flame at once, and like gun powder to destroy all. I did hear one say, that from an inch and halt once the flame from his candle grew to two feet long, and yet he escaped. Which makes it plain, that stagnant 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 the furnace, to any part o 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 is the best means to prevent so fatal an accident; and will likewise carry off all unwholesome vapors, damps or steams which may proceed from corruption of air, by stagnation's, or vapors 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 you price too great for these engines of yours?
Author. By what shall I 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 easier on convenience to you and your servants, and also much cheaper than any other engine ever used in your works, without which I could never propose nay advantage to my self by it. And to convince you of ht truth of my assertion, I dare understate the engine shall raise you as much water for eight pence, 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 eight pence saved out of every hundred pound. A brave astute 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 proportional 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, in so much as mine prevents your damps, an the evil effect of them. And as it will be my interest to allow these that first set my engine at work considerable advantages; so I hope I may assure my self 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 implied the best artificers to work on it, was not 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 learned 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 with the contrary, I fear this may prove some hindrance to the promoting of 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 effectual. 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 of 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 law of motion, knows it is an in fallible 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 proportionally less strength will do; if swifter, then the moving cause, as men hands, horses, and dead weight, then must the strength of the moving cause be increased proportional, 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 parts or wheels an engine consists of, and of consequence, the fewer parts or wheels an engine consists of, the easier it works. So that by barely looking on a pump, if it has more parts or wheels then the common work, you may conclude it worse; if a chain work or tub-work the frame. So that all that can be expected, is to make those go easier then 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 hear 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 of designing me; and that any persons may see my engine will perform, before they contract for it; there will be found no ground for the least suspicion in any person interested in implying them in mines. But to the contrary afford us a generous encouragement, in the business so conducive to increasing the mining trade, and thereby enrich themselves and the nation, and increase the king's revenue.
I could heartily with all miners, for their own as well as their countries 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.