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runner keeps the stream always supplied to a before we returned home. They told us in the certain degree, and when the lower hollow, which house that many had been disappointed in this feeds the syphon runner F H, is filled up to manner, and the common people superstitiously O H, both the common runner and the syphon imputed it to I know not what influence which runner feed the stream together, until the lower the presence of some people had over the founhollow is drained.
tain; for which reason they advised, that, in case In some places the most absurd tales are told it did not flow and ebb when we were both and believed by ignorant people respecting such present, one of us should absent himself, to try springs; their flowing and ceasing are ascribed whether it would do so in the presence of the to witchcraft; and designing men have some- other. Upon our return to it, the man, who times taken advantage of the credulity of others, was still at work, told us that it had begun to and gained credit for themselves, by fortelling flow and ebb about half an hour after we went the return of the spring after it had ceased, or away, and had done so ten or twelve times in less pretending to stop it when it was running. than a minute. We saw the stream coming into Some notions connected with superstitions of the basin, and likewise the others on the outside this kind are adverted to in the account given of of the basin began to increase, and to flow with an intermitting, or rather a variable spring, at great violence, upon which the surface of the Laywell, near Torbay, in Devonshire, by Dr. water in the basin rose an inch and a quarter Atwell, the first person who distinctly explained perpendicularly, in nearly the space of two these appearances by a reference to the nature of minutes; immediately after which the stream the syphon. It is a long mile,' says he, dis- began to abate again to its ordinary course, and tant from the sea, upon the north side of a ridge in nearly two minutes time the surface was sunk of hills lying between it and the sea, and making down to its usual height, where it remained two a turn or angle near this spring. It is situated minutes more; then it began to flow again as in the side of those hills, near the bottom, and before, and, in the space of twenty-six minutes, seems to have its course from the south-west flowed and ebbed five times ; so that an increase, towards the north-east. There is a constantly decrease, and pause, taken together, were made running stream which discharges itself near one in about five minutes, or a little more. I could corner into a basin, about eight feet in length, observe by the mark upon the stones, that the and four feet and a half in breadth, the outlet of surface of the water in the basin had risen, before which is at the farthest end from the entrance of we came, at least three quarters of an inch perthe stream, about three feet wide and of a suffi- pendicularly higher than we saw it; and I cient height. This I mention that a better judg- thought that I could perceive some very little ment may be made of the perpendicular rise of abatement each turn, both in the height, and in the water in the basin at the time of the flux or the time of its sinking; but the time of the increase of the stream. Upon the outside of the pause, or standing on the surface at its usual basin are three other springs which always run, height, or equable running of the stream, was but with streams subject to a like regular increase lengthened, yet so as to leave some abatement in and decrease with the former: they seem indeed the time of the rising, sinking, and pause al only branches of the former, or rather channels together.' discharging some parts of the constantly running It should seem, that, in the hill from which water, which could not empty itself all into the this stream comes, there are three hollows, or basin; and, therefore, when by means of the reservoirs, of different sizes, and connected by season or weather the springs are large and high, syphons of different widths. The times of the upon the flux or increase of this fountain, several increase and decrease lengthening, arises from other little springs are said to break forth, both the water sinking in one of the reservoirs, which at the bottom of the basin and without it, which makes it flow more slowly than when it is full. disappear again upon the ebb or decrease of the Having already briefly adverted to the princifountain. All the constant running streams put ple upon which the syphon acts, it will now be together at the time I saw them, were, I believe, necessary for us to show in what manner this more than sufficient to drive an overshot' mill, instrument may be employed as a prime mover. and the stream running into the basin might be The apparatus to which we allude was contrived one-half of the whole. I had made a journey, by Mr. C. A. Busby, the son of Dr. Busby, and purposely to see it, in company with a friend; termed the hydraulic orrery. The original apwhen we came to the fountain we were informed paratus, as described by Mr. Busby, in the forby a man working just by the basin, that the tieth volume of the Transactions of the Society spring had Aowed and ebbed about twenty times of Arts, is exceedingly complicated ; but the folthat morning, but had ceased doing so about lowing arrangement, as constructed by Mr. half an hour before we came. I observed the Partington, and employed by him in his public stream running into the basin for more than an lectures, will be found to possess much greater hour by my watch, without perceiving the least simplicity, and its construction will be easily variation in it, or the least alteration in the understood. A, fig. 7, plate II., represents a tin height of the surface of the water in the basin ; water-tight vessel, placed in a circular trough C. which we could observe with great niccty by The upper vessel of water is furnished with an means of a broad stone laid in a shelving posi- upright stem of wire, supporting a ball S, which tion in the water. Thus disappointed, we were is intended to represent the sun.
The smaller obliged to go and take some little refreshment at balls, E and m, revolve round the larger sphere our inn; after which, we intended to come back in the same time that the earth and moon repolre and spend the rest of our time by the fountain, round the sun, and as such, serve to convey a
tolerably accurate idea of the movements of each lie close, by its own weight, upon the hole those bodies. The syphon B may be considered in the bucket and box, until the engine begins to as the prime mover; as the lateral apertures at work. The valves are made of brass, and coD, by allowing the escape of a small portion of vered underneath with leather for closing the water from the lower extremity of the instrument, holes more exactly; and the bucket D is raised destroy the equilibrium within the tube, and and depressed alternately by the handle F and give a preponderance of power to the side which rod G c, the bucket being supposed at H before is opposed to the jet, and by this simple process the
working begins. an equable rotatory motion is produced : the Take hold of the handle F, and thereby draw whole apparatus Aoating round the central wire up the bucket from A to I, which will make that supports the sun.
room for the air in the pump to dilate itself, by The mode of constructing pumps must next which its spring is weakened, and then its force be examined. The common sucking-pump con is not equivalent to the weight or pressure of the sists of a pipe, open at both ends, in which is a outward air upon the water A : 'and, therefore, moveable piston, bucket, or sucker, in which is at the first stroke, the outward air will press up situated the valve. The piston is leathered the water through the notched foot B, into the round, so as to move freely, but not to admit any lower pipe, about as far as d: this will condense air between it and the pump-barrel. When the the rarefied air in the pipe between d and I to pump is worked, the piston is raised, and causes the same state it was in before ; and then, as its a vacuum between itself and the valve below; spring within the pipe is equal to the force or the external pressure of the air upon the surface pressure of the outward air, the water will rise of the water in the well then forces it up through no higher by the first stroke; and the valve by the lower valve to supply the vacuum, when the which was raised a little by the dilatation of the whole space between the valves is filled with air in the pipe, will fall, and stop the hole in the
At the next stroke of the pump, the box E; and the surface of the water will stand piston is forced down, and the water rises at d. Then depress the piston or bucket from I through the upper valve; when the piston, on to H, and, as the air in the part H cannot get being again raised, in addition to its former back again through the valve b, it will (as ihe operation, lifts up the water which had before bucket descends), raise the valve a, and so make passed through the upper valve, and discharges its way through the upper part of the barrel c, it from the spout of the pump; and this it con into the open air. But, upon raising the bucket tinues to do as long as the pump is worked. D a second time, the air between it and the waThus, every time the piston is raised, the lower ter in the lower pipe at d, will be again left at valve rises, and the upper one falls; and every liberty to fill a larger space; and so, its spring time it is depressed the upper valve opens, being again weakened, the pressure of the outwhile the lower one shuts.
ward air on the water A, will force more water As it is the pressure of the atmosphere which up into the lower pipe from d to e; and when causes the water to rise and follow the piston or the bucket is at its greatest height I, the lower bucket as it is drawn up; and since a column valve b, will fall, and stop the hole in the box E, of water, about thirty-two feet high, is of the as before. At the next stroke of the bucket or same weight as a column of air of equal area, piston, the water will rise through the box E from the earth to the utmost height of the atmo- towards H, and then the valve b, which was sphere, therefore, the perpendicular height of the raised by it, will fall when the bucket D is at its piston or bucket, from the surface of the water greatest height. Upon depressing the bucket in the well, must always be less than thirty-two again, the water cannot be pushed back through feet. For, independently of the inconvenience the valve b, which keeps close upon the hole in most cases of having so long a stroke, if it whilst the piston descends. And, upon raising were ever so much increased, the water would the piston again, the outward pressure of the never rise higher than thirty-two feet (nor indeed air will force the water up through E, where it so high, as it would have the weight of the valve will raise the valve, and follow the bucket to I. to lift), and there would be an empty space Upon the next depression of the bucket D it between the surface of the water in the pump- will go down into the water in the barrel H; barrel and the sucker, and consequently a consi- and, as the water cannot be driven back through derable loss of time and labor. 'But, when the the now close valve b, it will raise the valve a as water has once passed through the upper valve, the bucket descends, and will be lifted up by the it may be lifted by it to any height, if the piston- bucket when it is next raised. And now, the rod be made long enough, and a sufficient degree whole space below the bucket being full, the of strength employed, without ever lengthening water above it cannot sink when it is next dethe stroke.
pressed; but, upon its depression, the valve a The construction of pumps is usually ex- will rise to let the bucket go down; and when it plained to the student by glass models, in which is quite down the valve a will fall by its weight, the action both of the pistons and valves may be and stop the hole in the bucket. When the seen. In order to understand the arrangement of bucket is next raised, all the water above it will the common pump, we may refer to fig. 8, plate II. be lifted up and begin to run off by the pipe K. A is a vessel intended to contain water, which must And thus, by raising and depressing the bucket be deep enough to rise at least as high as from B to alternately, there is still more water raised by it; C. The valve a on the moveable bucket D, and which, getting above the pipe K, into the wide the valve b on the fixed box E(which box quite top L, will supply the pipe, and make it run fills the bore of the pipe or barrel at E), will with a continued stream.
The common sucking-pump may, by a small part of the house; and this without hurting or addition, be converted into a lifting-pump, titled obstructing its common uses. All that is necesfor propelling the water to any distance, and sary is, to have a large cock on the upper part of with any velocity. Fig. 9 is a sucking-pump the working-barrel, opposite to the lateral pipe whose working-barrel A B has a lateral pipe, c', in this figure. This cock serves for a spout, connected with it close to the top. This termi- when the pump is used for common purposes ; natein a main, or rising-pipe, furnished, or not, and the merely shutting this cock converts the with a vulve. The top of the workmz-barrel whole into an engine for extinguishing fire, or A B is shut by a strong plate, having a bollow for supplying distant places with water. It is neck terminaung in a small tanch. The piston- scarcely necessary to add, that, for these services, rod passes through this neck, and is accurately it will be requisite to connect an air-vessel with turned and polished. A number of rings of some convenient part of the rising-pipe, in order leather are put over the rod, and strongly com- that the current of water may be continual. pressed round it by another tanch and several It is of considerable importance that as equascrewed bolts. By this contrivance, the rod is ble motion as possible be produced in the mirin closely grasped by the leathers, but may be easily pipe, which diminishes those strains to which it drawn up and down, while all passage of air is otherwise liable. The application of an air arid water is effectually prevented. The piston vessel, at the beginning of the pipe, answers this is perforated, and furnished with a valve open purpose. In great works it is usual to effect ing upwards. There is also a valve T on the this by the alternate action of two pumps. It top of the suction-pipe; and it will be of advan- will be rendered still more uniform if four tave, though not absolutely necessary, to put a pumps be employed, succeeding each other at valve L at the bottom of the rising-pipe. Now, the interval of one quarter of the i mne of a comsuppose the piston at the bottom of the working- plete stroke. barrel; when it is drawn up, it tends to com. But ingenious men have attempted the same press the air above it, because the valve in the thing with a single pump; and many different piston remains shiut by its own weight. The air, constructions for this purpose have been proposer Therefore, is drawn throu in the valve L into the and execute. 11. 10 représents one of the best. rising-pipe, and escapes. In the mean time, It consists of a working-barrel abi, ciosed at the air, which occupied the small space between both ends; the piston c is solid, and the pistonthe piston and the valve T, expands into the up- rod passes through it collar of leathers at the top per part of the working-barrel; and its elasticity of the barrel. This barrel communicates lateis so much diminished thereby, that the atmo rally with two pipes n and fi, the communications sphere presses the water of the cistern into the being as ncar to the top and bottom of the barsaction-pipe, where it rises until an equilibrium rel as possible. At each of the communications is again produced. The next stroke of the piston, are two valves, opening upwards. The two downwards, allows the air which had come from pipes unite in a larger rising-pipe at bi, which the suction-pipe into the barrel durin: the ascent bends a little back, to give room for the pistonof the piston, to get through its valve. ( pon rod. Suppose the piston down close to the endrawin: up the piston, the air is also drawn off try of the lateral pipe hi ; when it is diawn up, through ihe rising pipe. Repeating this process it compresses the air above it, and drives it isrings the water at last into the working-barrel, through the valve in the pipe k, whence it esand it is then driven along the risins-pipe by the capes through the rising-pipe; at the same tine pinton. n.
it rarefies the air below it. Therefore the weight This is one of the best forms of a pump. The of the atmosphere huts the valve m, aud causes rarefacuon may be very perfect, because the the water in the cistern to rise through the valve piston can be brought so near to the bottom of 11, and fill the lower part of the pump. When the working barrel; and, for forcing water in the piston is pushed down again this water is opposition to great pressures, it appears prefer- fresh driven through the valve m, because it imable to the common forcing-pump; because in mediately shuts; and then most of the air which that, the piston-rod is compressed and exposed was in this part of the pump at the beginning to bendins, which greatly hurts the prind, by goes up through it, some of the water coining wearing the piston and barrel on one side. This back in its stead. In the mean time the air soon ren leis it less tight; and much water squirts which remaivel in the upper part of the pump out by the sides of the piston. But in this after the ascent of the piston, is rarefied by iis pump the piston-rod is always drawn, or pulled, riescent; because the valve o shuts as soon as the ivhich keeps it straight, and rods exort a much piston begins to descend, the valve p opens, the greater force in opposition to a pull than to com- wir in the suction-pipe h, expands into the pression. The collar of leather round the piston- barrel, and the water rises into the pipes by the rod is found by experience to be very impervis pressure of the atmosphere. The next rise of ous to water; and, though it needs but little the piston mit bring more water into the repair, yet the whole is very accessible; and, lower part of the barrel, and must drive a little in this respect much preferable to the common more air through the valve (), namely, part of pump in deep rrines, where every fault of the that which had come out of the suction-pipeh; piston obliges us to draw up some hundred feet and the next descent of the piston must drive of piston-rods. By this addition, 100, any com- more water into the rising-pipe k, and along mon pump, for the service of a house, may be with it most, if not all, of the air which remained converted into an engine for extinguishing fire: below the piston, and must rarefy still more the or may be made to convey the water to every air remaining above the piston; and more water
will come in through the pipe h, and get into convenience, and procuring a stream nearly the barrel. It is evident, that a few repetitions equable. At any convenient part of the rising wili at last fill the barrel on both sides of the pipe, beyond the valve S, there is annexed a piston with water. When this is accomplished, strong and capacious vessel V, closed at top by there is no difficulty in perceiving how, at every a small pipe T fixed into it, which reaches nearly rise of the piston, the water of the cistern will to the bottom of the vessel. When the water is come in by the valve nl, and the water in the up- forced along the rising-pipe, S, it gets into this per part of the barrel will be driven through the vessel, and rises above the lower part of the pipe valve 0; and, in every descent of the piston, the T. The air, which is above the water in the veswater of the cistern will come into the basrel by sel, being now confined, and being condensed the valve p, and the water below the piston will into a smaller space by the admission of more be driven through the valve m; and thus there water at each action of the piston, presses by its will be a continual influx into the barrel through elasticity upon the surface of the water, which the valves n and p, and a continual discharge cannot return by the valve S, and forces it up the along the rising-pipe l, through the valves m pipe T in a continued stream. This air-vessel
must be so large, that the change of bulk of the This machine is certainly equivalent to two compressed air, during the inaction of the piston, forcing-pnmps, although it' has but one barrel may be inconsiderable, otherwise the stream will and one piston; but it has no sort of superiority. not continue until the next stroke.
We must It is not even more economical, in most cases; not imagine, that because the stream produced because, probably, the expense of the additional by the assistance of an air-vessel is almost perworkmanship will equal that of the barrel and fectly equable, and because as much water runs piston, which is saved. There is, indeed, a sav out during the returning of the piston as during ing in the rest of the machinery, because one its active stroke, that it therefore doubles the lever produces both motions. It therefore can- quantity of water. No more water can run out not be called inferior to two pumps; and there than what is sent forward by the piston during is undoubtedly some ingenuity in the contriv- its effective stroke. The continued stream is
produced only by preventing the whole of this The forcing-pump represented at fig. 1, plate water from being discharged during this time, III., consists of a barrel A B, and a piston or and by providing a propelling force to act during forcer C. It is also provided with an air- the piston's return. It is, however, a matter of vessel v.
fact, that a pump, furnished with an air-vessel, When the forcer is first moved upwards in the delivers a little more water than it would do barrel, the air between that and the water below, without it. having room to dilate, by its natural spring, will În forcing-pumps it is of the utmost conseof course be rarefied; the pressure of the atmo- quence to avoid all contractions in the pipes. sphere being intercepted by the force of the barrel A The main, which leads from the forcing-pumps, Bon one hand, and by the upper valve at S in the should be equal to the working barrel. If branching-pipe, on the other, the water will rise it be only half the diameter, it has but onefrom the spring into A B, for the reason already fourth of the area; the velocity in the main is given; and repeated strokes of the piston will four times greater than that of the piston; and fetch
up the fluid to the forcer, and fill the cavity the force necessary for discharging the same of the pipes between the fixed valves D and S. quantity of water is sixteen times greater. It is The water in this manner raised, being hinderer not, however, possible to avoid these contracfrom going down again by the lower valve, will tions altogether, without making the main wider be pressed by the forcer every time it descends, than the barrel ; for if only so wide, with an entry and be thereby obliged to make its way where of the same size, the valve makes a considerable there is least resistance, viz. through the upper
obstruction. Unskilful engineers endeavour to valve at S. And whenever, on the rising of the obviate this, by making an enlargement in that forcer, this pressure intermits, the valve at S will part of the main which contains the valve. If immediately close under the weight of the upper this be not done with great judgment, it will water, and prevent its return that way, while increase the obstruction; for, if this enlargement the piston is rising with a fresh supply; and be full of water, the water must move in the dithis is repeated at every stroke of the forcer. rection of its axis with a diminished velocity;
It is evident that the operation of a pump is and, when it comes to the main, it must again be by starts, and that the water in the main remains accelerated. In short, any abrupt enlargement, at rest, pressing on the valve during the time which is to be afterwards contracted, does as that the piston is withdrawn from the bot- much harm as a contraction, unless it be so short tom of the working-barrel. It is in most that the water in the axis keeps its velocity until cases desirable to have this motion equable, and it reach the contraction. All angular enlargein some cases it is absolutely necessary. Thus, ments, all boxes into which the pipes, from difin the engine for extinguishing fires, the spout of ferent working-barrels, unite their water before water, going by jerks, could never be directed with it goes into a main, must therefore be avoided by a certain aim, and half of the water would be an artist who would execute a good machine; lost by the way ; because a body at rest cannot and the different contractions, which are unin an instant be put in rapid inotion; and the avoidable at the seats of valves, and the perforafirst portion of every jerk of water would have tions of pistons, &c., should be diminished, by put a small velocity. A very ingenious contris- giving the parts a trumpet shape. In the airance has been fallen upon for obviating this in- vessel, for producing a constant stream, this is of
very great consequence. The throat, or the end laid over the trunk, observing to break the joints. of the tube throngh which the water is forced by A third layer of boards, nailed firmly to the first the expansion of the confined air, should be and second layer, will complete the body of the always formed in this manner. A neglect of this pump, if of a common size (say five inches); but, seemingly trifling circumstance will diminish if the pump is larger, it may be strengthened by the performance at least one-fifth.
adding more layers of boards. The substitute for The requisites of a valve are, that it be tight, the upper box of the common pump consists of and of sufficient strength to resist the pressure to two isosceles triangular valves, the sides of which wliich it is exposed ; that it afford a free passage are double the length of the base, jointed with to the water; and that it do not allow much to leather to two square pieces of wood (hard wood, go back whilst it is shutting. The clack-valve is if convenient). These two pieces of board, to of all others the most obvious and common. It which the valves are jointed, play diagonally in consists merely of a leather flap, covering the the pump: Between these two pieces of board aperture, and having a piece of metal on the is fastened, with nails, the pump rod, which is upper side, both to strengthen and to make it also made of deal board : the leather which forms heavier, that it may shut of itself. Sometimes the joint should be extended over the sides of the hinge is of metal. The hinge being liable to the valves, so as to form the stuffing, as the be worn by such incessant motion, and as it is valves lie oblique?y in the angles of the pump. troublesome, especially in deep mines and under The inside of the valves may be loaded with water, to undo ihe joint of the pump, in order to sheet lead, if convenient; at any rate, they should pat in a new valve, it is frequently annexed to a be filled with as many nails as the valves will box like a piston, made a little conical on the hold without weakening them. The upper
valves outside, and dropt into a conical seat made for are furnished with a check string, to prevent the it in the pipe, where it sticks fast; and, to draw friction of the valves on the sides of the pump; it up again, there is a handle, like that of a basket, this check, which may be made of small line, is fixed to it, which can be laid hold of by a long very important to the ease of working the pump. grappling-iron. The only defect of this valve is, It should be so adjusted as to prevent the valves that, by opening very wide, when pushed up by from resting on the sides of the pump; the the stream of water, it allows a good deal to go leather only should touch the pump. The back during its shutting again.
lower valves, which are fixed to the bottom of The butterfly-valve is free from most of these the pump, are made similar to the upper valves, inconveniences, and seems to be the most perfect with the exception of the rod and check. Between of the clack-valves. It consists of two semi- the lower valves a piece of hard wood, for hookcircula flaps revolving round their diameters, ing up the valves, 'if no sheet iron or copper is which are fixed to a bar placed across the open- at hand, should be fastened. ing through the cistern. Some engineers make This pump works very easily, owing to the their great valves of a pyramidal form, consisting water-way by the valves being much greater than of four clacks, whose hinges are in the circum- the water way through common boxes. It is not ference of the water-way, and which meet with liable to choke, in consequence of the water not their points in the middle, and are supported by being wire-drawn below the boxes or valves; four ribs, which rise up from the sides, and for the water-way below the valves may be so unite in the middle. This is a most excellent contracted as to draw up even iron; but, by enform, affording a more spacious water-way, and larging the bottom of the pump, this will be shutting very readily.
remedied. There is another form of a valve, called the Plate III., HYDROSTATICS and HYDRAULICS, hutton, or tail-valve. It consists of a plate of fig. 2, is a side section of the pump; and fig. 4 the Icetal turned conical on the edge, so as exactly upper end of the trunk. AA, body of the to fit the conical cavity of its box. A tail pro- CC, pump rods: DD, upper valves: E E, lower jects from the under side, which passes through valves. a cross bar in the bottom of the box, and has a We may now notice the ingenious pump conlittle knob at the end, to hinder the valve from trived by Mr. Aust, for which he was rewarded rising too high. This valve, when micely made, by the Society of Arts. The advantages which it is unexceptionable. It has great strength, and is possesses over pumps of the ordinary constructherefore proper for all severe strains; and it tion depend on the curvilinear form of the barmay be made perfectly tight by grinding. Ac- rel, which allows, and indeed obliges, the rod, cordingly, it is used in all cases where tightness the handle, and the lever, on which it works, to is of indispensable consequence. It is most
be all in one piece.
Hence results, not only a durable, and the only kind that will do for pas- much greater simplicity in the workmanship, sages where steam or hot water is to pass through, and consequent cheapness, but a greater steadi
Mr. Perkins has contrived an ingenious and ness and precision of action, whereby more valuable ship's pump, which may be constructed water is discharged, and the leathering of the by sea-faring people while at sea, from materials valve will last a much longer time without wantthat are always found on board ; viz. deal boards ing repair. or planks, leather, nails, canvas, and tar.
Plate III., fig. 3, is a view of the pump, This pump is constructed as follows: take aa, the barrel, forming a curve of a quarter four strips of deal boards, of suitable width and of a circle, fixed at the upper end to the head length, nail them firmly together, so as to form a f, and at its lower to the pipe b: 66, the square trunk: this trunk is next covered entirely pipe that conducts the water into the barrel; it with tarpawling; then another layer of boards is is made curvilinear, in order that as little ob