|with the following label indicators:|
a, a, The furnaces.
b, B, the two fire-places.
c, the funnel or chimney.
d, the small boiler.
e, the pipe and cόck of it.
f, the screw that covers and confines its force.
g, a small cόck, a pipe going within eight inches of its bottom.
h, A larger pipe going the same depth.
i, a clack on the top of the said pipe.
k, a pipe going from the box of the said clack or valve, into the great boiler, about an inch into it.
l, the great boiler.
m, the screw with the regulator.
n, a small cόck and pipe going half way down the great boiler.
0, O, steam-pipes, one end of each screw to the regulator, and the other ends to the receivers.
p, P, the vessels called receivers.
q, q, the screws which bring on the pipes and clacks in the front of the engine.
r, r, R, R, valves or clack of brass, with screws to open and come at them upon occasion.
s, the force-pipe.
t, the sucking-pipe.
v, a square frame of wood, with holes round its bottom in the water.
x, a cistern with a buoy-cόck coming from the force-pipe.
y, a cόck and pipe coming from the bottom of the said cistern.
z, the handle of the regulator.
The operation of which is described as follows:
“The first thing is to fix the engine in a good double furnace, so contrived that the flame of your fire may circulate round and encompass your two boilers to the best advantage, as you do coppers for brewing. Before you make any fire, unscrew g and n, being the two small gauge-pipes and cόcks belonging to the two boilers, and at the holes, fill l, the great boiler, two-thirds full of water, and d, the small boiler, quite full; then screw in the said pipes again as fast and tight as possible; then light the fire at b.
When the water in l boils, the handle of the regulator, marked z, must be thrust from you as far as it will go, which makes all the steam rising from the water in l pass with irresistible force through o into p, pushing out all the air before it, through the clack, r, making a noise as it goes; and when all is gone out, the bottom of the vessel, p, will be very hot; then pull the handle of the regulator to you, by which means you stop o, and force your steam through o into the p, until that vessel has discharged its air through the clack, r, up the force-pipe. In the meantime, by the steam's condensing in the vessel p, a vacuum or emptiness is created, so that the water must, and will, necessarily, raise up, through t, the sucking-pipe, lifting up the clack, r, and filling the vessel, p.
In the meantime, the vessel, p, being emptied of its air, turn the handle of the regulator from you again, and the force is upon the surface of the water in p, which surface being only heated by the steam, it does not condense it, but the steam gravitates or presses with an elastic quality like air; still increasing its elasticity or spring, till it counterpoises, or rather exceeds the weight of the water ascending in s, the forcing-pipe, out of which, the water in p will be immediately discharged when once gotten to the top, which takes up some time to recover that power; which having once got, and being in work, it is easy for anyone that never saw the engine, after half an hour's experience, to keep a constant stream running out the full bore of the pipe, s; for, on the outside of the vessel, p, you may see how the water goes out, as well as if the vessel were transparent; for, as far as the steam continues within the vessel, so far as the vessel dry without, and so very hot [hot body], as scarce to endure the least touch of the hand; but as far as the water is, the said vessel will be cold [cold body] and wet, where any water has fallen on it; which cold and moisture vanishes as fast as the steam, in its descent, takes place of the water; but if you force all the water out, the steam, or a small part thereof, going through r, will rattle the clack, so as to give sufficient notice to pull the handle of the regulator to you, which, at the same time, begins to force out the water from p, without the least alteration of the stream; only, sometimes, the stream of water will be somewhat stronger than before, if you pull the handle of the regulator before any considerable quantity of steam be gone up the clack, r; but it is much better to let none of the steam go off, for that is but losing so much strength, and is easily prevented, by pulling the regulator some little time before the vessel forcing is quite emptied.
This being done, immediately turn the cόck or pipe of the cistern, x, on p, so that the water proceeding from x, through y, which is never open but when turned on p, or P; but when between them, is tight and stanch; I say, the water, falling on p, causes, by its coolness, the steam, which had such great force just before to its elastic power, to condense, and become a vacuum or empty space, so that the vessel, p, is, by the external pressure of the atmosphere [atmospheric pressure], or what is vulgarly called suction, immediately refilled, while p is emptying; which being done, you push the handle of the regulator from you, and throw the force on p, pulling the condensing pipe over p, causing the steam in that vessel to condense, so that it fills, while the other empties.
The labor of turning these two parts of the engine, viz the regulator and water-cόck, and attending the fire, being no more than what a boy's strength can perform for a day together, and is as easily learned as their driving of a horse in a tub-gin; yet, after all, I would have men, and those, too, the most apprehensive, employed in working of the engine, supposing them more careful than boys. The difference of this charge is not to be mentioned or accounted of, when we consider the vast profit which those who use the engine will reap by it.
The ingenious reader will, probably, here object, that the steam being the cause of this motion and force, and that steam is but water rarefied, the boiler, l, must in some certain time be emptied, so as the work of the engine must stop to replenish the boiler, or endanger the burning out or melting the bottom of the boiler.
To answer which, please to observe the use of the small boiler, d, when it is thought fit by the person tending the engine to replenish the great boiler, which requires an hour and a half, or two hours' time to the sinking one foot of water; then, I say, by turning the cόck of the small boiler, e, you cut off all communication between s, the great force-pipe, and d, the small boiler, by which means d grows immediately hot, by throwing a little fire into b, and the water of which boils, and in a very little time it gains more strength than the great boiler; for the force of the great boiler being perpetually spending and going out, and the other winding up, or increasing, it is not long before the force in d exceeds that in l, so that the water in d being depressed in d by its own steam or vapor, must necessarily rise through the pipe, h, opening the clack, i, and so go through the pipe, k, into I, running till the surface of the water in d is equal to the bottom of the pit, h; then steam and water going together, will, by a noise in the clack, i, give sufficient assurance that d has discharged and emptied itself into l, to within eight inches of the bottom; and inasmuch as, from the top of d to the bottom of its pipe, h, is contained about as much water as will replenish l, one foot, so you may be certain I is replenished one foot of course; then you open the cόck, i, and refill d immediately; so that here is a constant motion without fear or danger of disorder, or decay.
If you would, at any time, know if the great boiler, l, be more than half exhausted, turn the small cόck, n, whose pipe will deliver water, if the water be above the level of its bottom, which is half way down the boiler; if not, it will deliver steam.
So, likewise, will g show you if you have more or less than eight inches of water in d, by which means nothing but a stupid and willful neglect, or mischievous design, carried on for some hours, can any ways hurt the engine; and if a master is suspicious of the design of a servant to do mischief, it is easily discovered by those gauge-pipes; for if he come when the engine is at work, and find the surface, c, of the water in l, below the bottom of the gauge-pipe, n, or the water in d below the bottom of g, such a servant deserves correction, though three hours after that, the working on would not damage or exhaust the boilers; so that, in a word, the clacks being in all water-works always found the better the longer they are used, and all the moving parts of our engine being of like nature, the furnace being made of Stourbridge, or Windsor brick, or fire-stone, I do not see it possible for the engine to decay in many years; for the clacks, boxes, and mitre-pipe, regulator, and cόcks, are all of brass; and the vessels made of the best hammered copper, of sufficient thickness to sustain the force of the working the engine.
In short, the engine is so naturally adapted to perform what is required, that even those of the most ordinary and meanest capacity may work it for some years without any injury, if not hired or employed by some base person on purpose to destroy it; for after the engine is once fixed, and at work, I may modestly affirm that the adventurer, or supervisor of the mine, will be freed from that perpetual charge, expense, and trouble of repairs, which all other engines ever yet employed in mines for the raising of water, are continually liable unto.”
The following are the
The following are related quotes:
“When a comparison is made between Savery’s engine  and those of his predecessors, the result will be in every respect favorable to his character as an inventor, and as a practical engineer; all the details of his invention are made out in a masterly style, and accidents and contingencies are provided for, so as to render it a real working engine; whereas De Caus [Caus engine, 1615], the Marquis of Worcester [Worcester engine, 1663], Sir Samuel Morland [Morland engine, 1683], and Papin [Papin engine, 1690], though ingenious philosophers, only produced mere outlines, which required great labor and skill of subsequent inventors to fill up, and make them sufficiently complete to be put in execution.”
— John Farey (1827), Treatise on the Steam Engine; cited by Dionysius Larder (1840) in The Steam Engine (pg. 58) 
● Carnot engine
1. Savery, Thomas. (1701). The Miner’s Friend: an Engine to Raise Water by Fire. Publisher.
2. (a) Farey, John. (1827). A Treatise on the Steam Engine: Historical, Practical, and Descriptive. Longman.
(b) Lardner, Dionysius. (1840). The Steam Engine: Explained and Illustrated – With an Account of its Invention and Progressive Improvement and its Application to Navigation and Railways; also Including a Memoir of Watt. Taylor and Walton.
3. Thurston, Robert. (1878). A History of the Growth of the Steam-Engine (txt) (pgs. 31-35). Appleton and Company.
● Savery engine – GSU.edu.