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HYDROSTATICAL PARAVOX, WEIGHT OF THE ATMOSPHERE ETC. 5 cases. Hence it follows, that a body im- same nature as the heat proceeding from mersed two inches deep in the seu, will a fiery body. not be pressed on with a greater force "If we suppose, then, that the rays of than if it were immersed the same depth the sun, wherever they shine on our earth, in a basin of water.

possess the property of accumulating the particles of our atmosphere, both questions may be easily answered. In this supposition I must be allowed to differ with C. D. Y., as I think the atmosphere, where the sun shines most, is accumulated, and, consequently, increused both in height and density.

I must yet beg a little more room, just to notice the question on the Syphon (page 286). The reason is, because the depth of the water is greater in the long leg than in the short one; it is, therefore, of greater pressure at the extremity ot, the leg, consequently the fuid descends, because it overbalances the pressure at the extremity of the other leg. As there cannot be a vacuum between the legs,

the weight of the atmosphere pressing I will now endeavour (as briefly as on the surface of the fluid in which the possible) to account for the pheno- shorter leg is immersed, supplies the dismenon in question;-Let a (in the above charge by forcing it up the short leg. figure) be a vessel, bca tube fitted to If I have stated any thing that is incorit, and filled with water to the top, rect, nothing would give me greater pleab; the upper stratum of particles, sure than in being set right by some of from c to d, will be pressed on with the your better-informed Correspondents. same force as those from e to c; because I cannot conclude without bestowing The column bc, meeting with these par my warmest approbation on your valuable ticles at c, presses them outwards or and useful Magazine, for thus encouraging sideways, and, as they cannot escape the useful and scientific inquiry; for directing pressure, on account of the top and sides the attention of the middling and work of the vessel, they must therefore exerting classes to subjects which otherwise, the same force doxonwards as those from perhaps, they would never have thought c to c; consequently the bottom, ee, of;, and for affording, to all, a better will be pressed on with the same force medium through which to express their as it would if the vessel were made of wishes, thoughts, and experience, than the bulk of ee, ff, and filled with water had existed before its commencement. to the top.

I remain, Sir, I will now notice the questiou on the

Yours very respectfully, Weight of the Atmosphere (page 332), as it is, in some measure, connected with

J. E. COOMBS.

Bath. the foregoing subject; I will also include the following one, and endeavour to answer them both together. How is it that the atmosphere is thicker

SIR,-Should the following answers or more dense in warm weather than in to your Correspondent, + W. X. (p. 285, cold, when, from what we know of heat, vol. 111.) appear worthy a place in your it possesses the property of rurefying useful Magazine, I should feel much air?

obliged by their insertion. To answer these questions I will first First. Why an additional pint of water give you my opinion of the nature of the will have the effect of bursting a hogsheat we receive from the sun. I do not head filled with that fluid, if introduced believe that the suu is a body of fire by a small tube of sufficient height ? (which is the opinion of many), but that No part of any contined body of water it is an opaque body, like our earth, sur. (excluding the consideration of its own rounded by a luminons atmosphere, the rays of light from which, mixing with our atmosphere, produce the heat that bypothesis, but will not now take up we feel ;* thus, then, the heat we feel more of your valuable room than what is as proceeding from the sun, is not of the necessary to the explanation of the pre

sent question; however, should any of

your Correspondents deein it requisite, * As I never believe any thing, except I would gladly resume this subject, and I am convinced in my own mind of the give my reasons and arguments, which reasonableness of my belief, I could ad- would, I think, render the truth of what doce many arguments in favour of this I have already said beyond a doubt.

6 HYDROSTATICAL PARADOX, WÉIGHT OF THE ATMOSPHERE, ETC. generally brings with it a quantity facts on their minds, before I proceed to of hydrogen, contaminating the the explanation of one of the most singu

lar properties of fluids : whole mine, and preventing the at

The force of gravity, or the attraction mospheric current from circulating.

of the earth, which constitutes the In these cases, if fire is introduced weight of matter, is only exerted perpenamongst it before the fresh air is dicularly downwards, or in a direction taken from the shaft, an explosion

tending towards the centre of the earth; *is the inevitable consequenceman

this force produces different effects on a

fluid than it does on a solid body, on acexplosion of so tremendous a nature,

count of the different property of the that the ‘Land-drainer's strong box,' particles of which it is composed. The I am afraid, would not be able to particles of a solid body attract each resist it.

other (called the attraction of cohesion), If I might be allowed to offer a

and it is this property that constitutes

its solidity, while those of a fluid repel few hints to the ventilators of col

each other; consequently they are unable lieries, they would be

to support themselves, and will, if not .). Never allow your air to traverse confined, extend themselves in every too great an extent of workings, direction till they arrive at a level. particularly old ones; but let your downcast and upcast shafts be conpected by shorter ways than is geperally done. Many accidents I could mention have occurred from want of this precaution, and I am afraid the only plea for the neglect

Suppose a body of water to be comthat can be made is the saving of

posed of numerous strata of inconceivably expense.

minute globular particles (see the above 2. Never trust too much to one figure) : as I have shown that these parfurnace. If your mine be foul, ticles repel each other, the attraction of divide your air, place two furnaces

gravitation must exert itself on each near your upcast shaft, and keep

particle, separately; consequently the

particles of stratum a will press on your two currents from communi

those of b with their own weight or cating' till they have passed over gravity only, and those of stratum b will the fire.

press on those of c with the weight of 3. Make all your air-courses large,

both a and l, and so on to the last straand take particular care that your

tum, which will support the weight of

all the others; each particle of stratum stoppings, brattin, * &c. be tight. a pressing on the two inımediately under I am, Sir,

it, and each particle in stratum b partially * Your obedient servant,

pressed on by the two particles above it. E. B. C.

as shown by the figure. Now, any par

ticle in any of these strata may be consiH , Durham...

dered as pressing upwards, sideways, &c. with the same force as it is pressed on by the particles above it, on account of

the resistance occasioned by the repelling ON THE HYDROSTATICAL PARADOX, property of that particle, which makes it

WEIGJIT OF THE ATMOSPHERE, endeavour to escape the pressure. But " THE CENTRE OF GRAVITY, AND

when it presses downwards, its own

weight or gravity must be added; couseTHE SYPHON.

quently it must press downwards the SIR-Seeing that none of your nume. weight of the particle more than it does rous Correspondents have undertaken in any other direction. Hence arises the the solution of the question on the Hy- increased pressure of every stratum from drostatical Paradox, I will venture to top to the bottom. The horizontal exoffer my opinion, and endeavour to ac

our to ac- tent of a body of water has nothing to count for the phenomenon in the most do with this vertical pressure, for, if the concise, simple, and reasonable manner first or top stratum extend many square I possibly can, that it may be fully intel- miles, the particles of which it is comligible to the whole of your readers. I posed cannot press more on the second should wish to impress the following stratum than they would in a small tube,

because a particle in the second stratumi

will only be partially pressed on by the : * Brattin is a deal partition, to direct two above it, and the weight or gravity the circulation of the air.

of these two particles is the same in botlı HYDROSTATICAL PARADOX, WBIGHT OF THE ATMOSPHERE, ETC. 7 : Let A (fig. 1) represeut a tube inserted part of the greater column is imme. into a yessel, B, filled with water, the diately counter-exerted by each of the lower end of which tube circumscribes remaining five parts on the internal surthe space of half an inch. Let A (fig. 2), face of the confining vessel surrounding in like manner, be a tube, enclosing, by the bottom of the tube B, agreeable to its lower end, an area of three inches. the law before mentioned, that no part Now, suppose the two vessels, B, B, to of any body of fluid can be made to suscontain equal quantities of water, and tain a greater preseure than each of the that the tubes, A, A, being of equal remaining equal parts of the same height, height, are also filled with that fluid ; if unconfined, nor of any height (exthen, although the tube A (fig. 2) con- cluding the consideration of its own gra. tains six times as much water as the 'vity) in a confined state. By the interother, the weight of that water being vention of any solid body, as the peg in exerted on six times as much space, fig. 3, between a column of water and both vessels must sustain an equal in- any other mass of water in a confined terpal pressure. Consequently, if the state, though that columy, in a state of greater column were only half as light, free communication, would impress only it could have only half the force of the its natural weight, yet, by such interlesser. But if A (fig. 2) be closed at the vention of a solid body, its force may be bottom, and have a short peg attached increased or diminished in an infinite to it (a3 represented in figure 3), the degree by the diminution or increase of area of the bottom of which peg being that part of the solid intervening body half au inch, and it be properly in which presses on the confined mass of serted into a vessel of equal size with fluid, exactly fitting, as a matter of the two former, then will the internal course, the opening of the confining vespressure sustained by such vessel be six sel into which it is introduced, which, times as great as before the space being however, is only a different modification contracted five-sixths under the same of the experiment described in the first weight. Also, if any given weight be part of this letter. impressed on the water in the tube of "To conclude (which I beg pardon, Sir, fig. 1, and an equal weight on that in I have not doue loug ago), it is not diffithe tube of fig. 2, then will that weight cult to believe that a sphere of water at exert itself with six times greater force the centre, with a sinall columu extended within the former vessel than within to the surface of our earth, need not be the latter, the space it is impressed upon comparatively very great to put it in the being five-sixths less.

power of the atom called man, to burst Suppose, again, that the sides of the this stupendous world like a bubble, two first vessels were raised, as repre- provided the matter enclosing the sphere sented by the dotted lines, to the height and projected column Le so compact as of the tubes, and then filled with water not to allow any portion of the fluid to (the tops of the vessels, in the first state, insinuate itselfiuto greater space without being considered as taken away), the rending asut

surroun mass; pressure on the bottoms of the vessels and probably the weight of the columy only on the sides, as high as they were at first, would be equal to such an effect; for, would be precisely the same as before; taking the semidiameter of our globe nor would it be greater were the horizon at 4000 miles, and deducting 250 miles tal dimeosions of the vessels increased for the semidiameter of the sphere six thousand times, or any less if in an of water, the coluinn would impress equal degree contracted; that is, it a weigh: of 9,556,250 pounds upon wonld not be any greater or any less on every inch, and the whole force with equal spaces at equal heights. For if which the sphere would be made to two columns of water, A and B (fig. 4), exert itself, in order to bring the commuuicate at bottom, though Å be column within its own circumference, six times as large as B, yet will B sus- would be 30,130,666,384,696,000,000,000 tain A, because all communicating co pounds, or 13,451,190,351,400,000,000 lumns of water will maintain their level; tons; on which grand hydrostatic princonsequeutly, though B should be made ciple may, probably, be accounted for as great as A, it would still do no more the present geological appearance of our than sustain it. The column A, in the earth. first case, not exerting the whole of its I trust + W. X. will be able to make weight against the column B, but only make up, by his own reflection, for the that of a column equal to B, its remain- brevity with which I am obliged to aning five equal coluinns being sustained swer his two remaining questions. It is by the parts of the confining vessel sur- the change in the centre of gravity that rounding the bottom of the tube B; gives preponderance to the pea of a steelyet, on the other hand, the column B, yard, on removing it further from the though only a sixth part as large as A, fulcrum, and, to recover the equilibrium, does exert a force equal to the weight of either the fulcrum must be placed in the its opposite column, because the force new centre of gravity, or an additional with which it presses upon the sixth weight must be suspended at the other

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end, in order to restore that centre to its which they are covered are unhealttafel old place. The centre of gravity, per- to the operatives, on account of their haps + W. X. is aware, is that perpen- coldness. The plank-floors, though thy dicular line in any body, the product of are both cheaper and firmer than those the weight and distance on each side of on the old plan, have nevertheless their which is equal to the product of the disadvantages ; for though the floor may weight and distance on the other; hence be inade, yet let the timber be ever so what is lost in distance is gained in well seasoned, when the rooms are ready weight, the reason of which is, that ve- for use, and must be kept up to the relocity is power: and the further from quired temperarure, the joists wi the fulcrum the extremity of a lever, the and the floor becomes pervious to both greater its velocity, which velocity gra- dust and water, which, with the tremor dually diminishes to the centre of motion; produced by the machinery at work, consequently the nearer the end of the creeps round the dowels or tongue, and steelyard you suspend the pea, the greater the consequences are serious to the mais the velocity by which you have to mul chinery underneath. Besides, when the tiply its weight. It is the pressure of floor has become so deteriorated as to the air, not gravitation, that causes the require repairing in the passages, the phenomenon of the syphon; the greater whole length of the planks must be weight of water in the longer leg giving taken up, from beam to beam, which the air pressing ou the end of the shorter will be attended with bad consequences a proportional advantage over that press to any machinery that may stand upon ing on the end of the former. It is this, them, or to any fixtures onderneath. + W. X., that “ pulls the water down . These considerations have induced me the good-natured leg."

to turn my attention to this subject. I I am, Sir,

propose that, instead of three - inch Your very obedient servant,

blanks, one and a half shall be used, laid J. W.

upon irou beams, in two courses, one

upon another; they shall both stretch Hirwain Iron Works.

the same way, and the upper boards shall break the joints of the lower ; underneath the upper, and above the

lower joints, slips of sheet iron, about FIRE-PROOF AND PLANK FLOORS.

three inches broad, must be laid, and · SIR,- The imperfection of the old con- kept in their places with a few nails; it struction of Floors for the purposes of will be necessary to screw the boards machinery, has induced some people in together in several places, to give them this neighbourhood to alter the flooring firmness. When this floor is finished, system altogether; and instead of joists, the joints will be good, and remain so, tsooring-hoards, tiering underneath, &c. whatever temperature they may be ex(of wbich they formerly consisted), two posed to. They will have another adplanks, of quite a different nature, have vantage over the present plauk-floors; been adopted, viz. fire-proof and plank when the upper course is done, they may floors.

be renovated without breaking through For the fire-proof floors, the columns the floors. and beam are made of cast iron, and are Another improvement may easily be secured in their places with wrought made in the iron columns. Let their iron bars, that trayerse from beam to diameter be as great as convenient, for beam; upon a margin underside the the purpose of enlarging their internal beams spring the arches of brick-work; capacity, and let these are filled to a level on their upper room have a cock, or any other appliside with rubbish, aud are covered with cation, for the purpose of emission : flags or tiles.

there must be a cistern on the top of the For plauk floors, iron columns and building (in case of accidents by fire, or beams are used; but the beams are flat for any convenient purposes where water ou their upper side for the planks to lay may be wanted), and this cistern must upon; three-inch planks are then jointed be attached to the lifting-pump of the aud ploughed on the edges, for the pur- steam-engine. It will be necessary that pose of admitting slips of sheet-iron each column be connected either at top (called tongues) to enter balf-way into or bottom, so that the water may flow each plank, so that no dust may get through the whole, and they must likethrough from the upper side.

wise have air-pipes attached to them. These are certainly improvements on Now, suppose the columns to be five the old plan, as they possess the advan. inches bore (which is common), and the tages of stability, and deprive vermin of building six stories high, the average their harbours. The advantage of fire- height of the stories nine feet six inches, proof floors are steadiness, durability, length ninety feet by forty-eight feet, it and saving the insurance : but then the will then contain eighteen columns fiftyfirst expense is great ; they take up more seven feet long each, making in the whole bead-room, and the tiles or flags with a colump of water one thousand and

each co

erv

SKETCH OF THE UNDER PART OF A THRER-WHEELED CARRIAGE. 9 twenty-six feet long, and five inches zoutal pipe in the roof (made of sheet diameter. Now, 5 x 5 x , 7854 = 19,635, irou), and of sufficient capacity to give area of bore; 19,635 x 57, length of co- them draft. This pipe niay be inserted lumu, = 13450,34, contents of one co in the chimney, provided it is made to lumn; and 13430,34 x 18,=872, imperial dip a little before it enters, te prevent gallon. Here, then, is a capillary supply sparks or soot descending into the rooms: of water in every part of the building, by this means the rooms may be ventiwhich may be constantly maintained by lated from a great portion of dust, imfeeding the cistern above froin the pure air, and superfluous heat, without engine. The importance of an imme opening the windows. Should this be diate and convenient supply of water in doubted, let it be remembered that the every part, and in such extremities, needs sum of the orifices of the vertical pipes no comment.

amounts tu no less than 353,43 square But they may be made useful in ano- inches. ther way, viz. 'as ventilators. Let there

I am, Sir, be openings in each column, near the Your most obedient servant, ceiling in every room, and let the whole of the columns connect with an hori Mauchester, Feb. 13th, 1825.

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Sir,-May I request you to insert to which the shafts may be attached ; D, the above Sketch of the Under-part one of the hind-wheels. The perch is of a Three-wheeled Carriage in your

fixed on the centre of the hind axle.

The body may be neatly set upon lanceinteresting Magazine. I hope some

wood; and should the above be thought of your numerous readers will please

a practicable plan, I shall furnish you to examine it, and point out any im with a drawing of the carriage complete, provement they may observe.

which will be entirely duty free, and

most likely very acceptable to your readDescription.

ers who have not an opportunity of AAA is the perch, with a rise in front, visiting G. M. in Long Acre (vol. II. to admit of a larger fore-wheel; C, the page 364). fore-wheel, attached to the perch by the

Tam, Sir, iron frame, E, moving in a collar at S, . A TRUE WELL-WISHER. to enable it to turn; B, the splinter-bar, ........, North Britain.

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