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NEW METHOD OF HEATING GREENHOUSES, &c. Mr. URBAN,
Derby-street, Parlia. unfit communication to make to this
ment-street, April 19. meeting. S of a very cheap,
this heating Green-houses may be accepta
If from the side of any open boiler, ble to many gentlemen who are read- two pipes proceed horizontally, comers of your widely-circulating Miscel-municating at their extremities at any
distance from the boiler; and the lany, I beg to inclose a short paper on
boiler be filled with water to such a the subject, which I read to the members of the Institution of Civil En.' height that the surface of the water gineers at their last meeting.
may be above the orifice of the upper Yours, &c.
pipe, where it joins the boiler; on making a fire under the boiler, the
water will begin to circulate along the On a new Method of healing Green- pipes, and continue so to do whilst houses, Conservatories, &c. By W.
any fire is kept under the boiler; the Cubitt, Civil Engineer, read lefore the Institution of Civil En- from the boiler, and returning by the
water passing along the upper pipe gineers on Tuesday April 10, 1827.
lower pipe to the boiler. The same The object of this communication effect will also take place, if instead of is to explain a mode of heating Green- joining the pipes at their extremities, houses, Vineries, Pine Pits, &c. by they be made to terminate in a cistern means of hot water circulating through of water on the same level with the pipes, instead of the usual method of boiler. The water will still continue brick Aues, or the more improved me- to circulate as before, and continually thod of steam pipes.
keeps changing the water from the During the early part of the last boiler to the cistern, and from the Session, and before I had the oppor- cistern to the boiler, as long as any tunity of regularly attending the meet, fire remain, and at any temperature of ings of this Institution, I understood the water, between the natural temthat this subject had been before the perature at the time, and the boiling Society, and some forms of apparatus point. for the purpose stated and discussed, In describing the apparatus, as used upon
which much difference of opi- by Mr. Bacon, I believe I cannot do nion existed as to the practicability better than qurole the very words of and utility of the plan.
the gardener (Wm. Whall), from a During the last week, I have had letter he had just written with his an opportunity of seeing this inethod master's permission to a gentleman, of warming hot-houses as successfully with information on the subject. In carried into effect by Anthony Bacon, describing one of the vineries, he says, esq. (an associate member of this Institution), at his seat at Elcot Park; wide inside, heated by a boiler placed in a
“ The house is 40 feet long and 10 feet near Newbury; and as this method
recess in the middle of the back wall; the appears to me to be superior to any fire-place under the boiler is got at from a other mode I have yet seen or heard back shed; the boiler is two feet six inches described, I trust that a general de long, one foot six inches wide, and one foot scription of the apparatus, as erected by eight inches deep; from the end of the Mr. Bacon, will not be deemed an boiler four cast-iron pipes proceed horizon
[April, tally of 34 inches diameter; two of them “Steam may do very well on a large are joined to the boiler just above the boto scale, and when there is constant attention tom, and the other two just below the sur- to the fire both day and night; but the ubface of the water ; the house is divided by jections are the great expense of a steam glazed partitions into three compartments, boiler and the apparatus belonging to it, for the convenience of forcing one part with the frequent repairs that are required, and out the other; the middle compartment is the necessary attention to the fire, which is two lights in width, and the extreme com- as great upor a small as on a larger scale, partments four lights wide; the pipes from besides this there is a greater risk of explothe boiler proceed horizontally to the front sion in a hot-house steam boiler, than in wall, where they divide, one upper and one that of a steam engine, for steam engines lower pipe proceeding to the east compart- have generally persons properly instructed ment, and the other two pipes to the west, to manage them, but gardeners or their asand are carried to the ends of the house, sistants cannot be so competent. where they join to cast-iron cisterns or re- “ The heating with hot water has gone servoirs at each end of the house, which of the objections I have mentioned of flues reservoirs are 3 ft. 6 in. long, 1 ft. 6 in. and steam ; the apparatus is simple, and not wide, and 1 ft. 8 in. deep, having loose iron liable to get out of order: the boiler has covers ; these reservoirs are filled with wa- only a loose wooden lid, and no safety valves ter, which communicates by the pipes with are required; the quantity of fuel consumed the water in the boiler,
is very moderate, and when once the water “When the boiler pipes and reservoirs is heated very little attention is required, are filled with water, and a fire lighted under for it retains its heat for many hours after the boiler, the water in heating ascending to the fire is gone out." the top of the boiler, passes along the up
Such are the remarks of a practical per pipes to the reservoirs, the cold water finding its way back to the bottom of the man, and one who has had much ex. boiler through the under pipes, and the cir- perience with flues and the manageeulation continues regular as long as there ment of hot-houses and conservatories is any heat under the boiler ; the hot water on the usual plan. He decidedly preflowing through the upper pipes to the re- fers the plan of heating with hot waservoir, and as it cools returns back to the ter, and has petitioned his master 10 boiler through the under pipes.
have all the hot-houses and pits put “I have repeatedly after the water has upon that plan, and by which also a been heated, immersed a thermometer in the reservoirs at the ends of the house, and very large conservatory adjoining the have only found a difference of three or four witness to the correctness of the gar
new house is to be heated. I can bear degrees between that and the water in the dener's description, having seen the boiler ; it is not necessary to make the water boil
, consequently if the fire is judi- thing in operation. ciously managed, no steam will be raised, The great advantages of this method and no water wasted, but it is necessary to
above others, are economy, simplicity, examine the boiler, and add water when any and facility of management; to what is evaporated.
extent it may be possible to carry it “ In Mr. Bacon's two pine pits, a fire- with advantage, remains for expeplace with a boiler over it, is placed between rience to prove; but the very successthem; they are each 30 feet long, and 10 ful manner in which Mr. Bacon has feet wide; the western pit is heated by hot carried it into effect, makes me think water pipes, the eastern one by a common it an object worthy the attention of all Alue, heated by the same fire after it has who are in any way concerned in purpassed under the boiler. During the severe
suits of this kind, and will form a sufnights of last winter, thermometers were
ficient excuse for my trespassing so long suspended in these pits and examined
every morning; when the pits were uncovered, on the attention of the meeting; and as that heated by the hot water was invariably some description may probably arise from 7 to 9 degrees higher than the flued on this subject at future meetings of pits.
the Institution, I shall conclude by “ Brick flues, from the numerous joints proposing the following question for and the mortar cracking, are subject to give consideration, viz. out at times a sulphurous gas, which is in- What is the best form of boiler, and jurious to plants, and even with two fire- proportional size and perpendicular places in a house forty or fifty feet long, it distance of pipes, regard being had to is impossible to keep up an equal tempera- their length, to produce a maximum ture in the whole length; the houses get effect in heating Green-houses, Con. overheated in the neighbourhood of the fire- servatories, &c. on the above plan? place, and it is difficult to keep up a proper temperature at the extremities of the flues.
293 Mr. URBAN,
Poughill, Devon, impossibilities in the attempt to ac
April 12. quire knowledge, and often exaspe. THE
He phenomena of the globe rated with the scanty means afforded
which we inhabit are so interest- it to make the acquisition. It is ening in themselves, and so intimately tertaining to imagine Burnet bringing connected with almost every other up the waters of the Deluge through branch of natural philosophy, that the broken crust in which he fancied their development has occupied the they had been confined during the anattention and exercised the inventive tediluvian period; and after he has ingenuity of the most celebrated philo- perinitted them to effect the universal sophers of every age. Most of the an- devastation, we are still interested to cient as well as the modern cosmogo- find him collecting them into fathomnisis endeavoured to investigate the less oceans, and piling the fragments original condition of the constituent of his shell until they become the parts of the earth, but their duration loftiest mountains. It is pleașing to on an exceedingly confined spot of the let fancy follow Woodward through great theatre of Nature has been too his process of suspending cohesion momentary, and consequently, their amoug the particles of the globe, reobservations have been too limited to ducing all its matter to a soft paste, trace with precision the various changes, and then forming a new earth from combinations, and decompositions, the immense heap of mortar. In pewhich have been effected on the sur- rusing the theory of the extraordinary face of the globe, by the numerous Whiston, who could not make a globe agents that have altered it, an indu- without calling a comet to his assistbitable proof that the attention of a ance, we almost participate in his
promoment, as it were, is not sufficient phetic fear that the near appulse of one to account for operations which have of these harmless celestial visitants may employed the ever-working hand of at some distant period occasion anoNature for ages to produce. Thus ther deluge. Lastly, the celebrated finding their resources too circum- Count de Buffon, surpassing all his scribed to explain the grand pheno- predecessors in vividness of fancy, and mena around them, the imagination all the other system-makers in richwas called upon to supply the requi- ness of language, delights us with the site desiderata, and from this fertile description of his imaginary supposisource they obtained not only an ex- tion that our earth was once only an planation of the different modifications excrescence on the face of the Sun, which are continually occurring on which being dexterously struck off by the surface, but even the materials that the collision of a comet in a state of form the nodule at the centre were liquefaction by fire assumed its present analysed with apparent exactness, or form. His theory, which is the oriin the absence of matter, a description ginal offspring of a fine imagination, of the central cavity was readily sup- is so illusory, that in reading it, it is plied. Although the results of these difficult to retain Reason on her seat reveries which have been commonly we are balf iuclined to forget that had termed theories of the earth, are cal- the earth been struck off from the Sun, culated to give us a better idea of pri- it would move in an orbit that passes meval chaos than can easily be formed through the Sun, instead of having the without them, we must, notwithstand- Sun for its focus, and thus would fall ing, acknowledge ourselves indebted to into the Sun again, and terminate its those ingenious writers who have la- career at the end of the first revoluboured so industriously to form ideas tion. concerning the great phenomena of These are some of the most celethe earth, for the source of rational brated and popular writers who have amusement, if not of sound philoso- favoured us with theories of the earth. phy, which they have left us; it is, Each author has his disciples and adsays an author, an ample compensation vocates, and therefore since their theofor coriosity, even while we want the ries differ so widely from one another, force of conviction. We feel enter- it is not wonderful that there are so tained in perusing their productions, many surmises extant respecting the however fanciful their hypotheses, or constituent parts and original construcimaginary their theories; for in their tion of the earth, especially as they are works we find genius contending with a subject on which every one is privi
(April, leged to enjoy the opinion that he (vide ubi supra), “however the plachooses to adopt.
nets have been formed while they were Your ingenious correspondent Col. in fluid masses, all the heavier matter Macdonald has recently published subsided to the centre.” The great some articles in this Magazine, in distance of the centre of the earth which he advances an opinion that from its surface, precludes all possithe earth is hollow, and he endeavours bility of our actually ascertaining its to establish his notion on the autbo- constituent central matter, but we rity of some expressions in the sacred may form reasonable conjectures. history of Moses. With a reverential The atmosphere which surrounds and regard for the authenticity of the Mo- revolves with it has been found to be saic relation, and a due deference for much rarer at a considerable altitude, the gentleman whom I have just than it is near the earth's surface, the named, it may be asserted that his densest part of it contiguous to the hypothesis is in direct opposition to earth is much lighter than water, and the opinion of philosophers of the first water is of less density than the matorder, and to the inferences drawn ter composing the surface, and again, from very satisfactory experiments. the materials of the surface are not so Sir Isaac Newton says (Princip. Prop. heavy as those which constitute the 10, Lib. 3), “ Since the common mat- strata of mines ; hence, then, reason. ter of our earth on the surface thereof ing from analogy, and without assumis about twice as heavy as water, and ing too great a license in doing so, are a little lower, in mines, is found three we not justified in concluding that or four or even five times more heavy, there is a greater probability of the it is probable that the quantity of the earth's being denser at the centre than whole' matter of the earth may be five it is at the surface ? or six times greater than water." May Maclaurin, in his Fluxions, $ 868, not a conclusion be fairly drawn from has submitted Dr. Halley's supposithis, that Sir Isaac supposed the matter tion that the earth is hollow, with a of the earth more dense at the cen- nucleus included, to a mathematical TRE than it is at the surface? The investigation, but from the result, he same unrivalled philosopher surmised, does not appear to insist on the conseand experience authenticates the fact, quences that would follow from such a that heavy bodies endeavour to de- constitution of the internal parts of the scend towards the CENTRE of the earth. In the concluding part of the earth. It
be asked, to where do article he says, “When more degrees they tend? The answer is, if Col. shall be measured accurately on the Macdonald's hypothesis be true, to an meridian, and the increase of gravitaempty nothingness: if we admit the tion from the equator towards the pole truth of Newton's established law, determined by a series of many exact and at the same time suppose the observations, the various hypotheses earth a shell, we tacitly acknowledge that may be imagined concerning the that we entertain the strange notion internal constitution of the earth, may that all heavy bodies have an innate be examined with more certainty." propensity to fill the central cavity. Since the above-named celebrated maThe penetrating genius of Newton dis- thematician wrote the preceding pascovered, and the discovery has been sage, many admeasurements have been verified by inany accurate admeasure made in different places by Colonel ments and experiments, that the fi- Mudge, the French academicians, &c. gure of the earth is that of an oblate but perhaps no admeasurements or exspheroid, which is the figure that a ho- periments which have been effected, mogeneous fuid assumes in revolving have afforded so conclusive an inferon an axis : if we admit, then, the sup- ence with respect to the component position of geologists, that the earth matter of the earth, as those made at was in a fluid state at the commence- the mountain Schillellian, under the ment of motion, we must deny that it superintendance the late Dr. Maskeis at present hollow ; for by the laws line. The outlines of the various exof gravitation, the heaviest bodies ar- perimental operations were submitted ranged themselves round the centre, to Dr. Hutton for calculation, to deand the progressively lighter ones on duce from them the real mean density the surface of the foregoing ones. This of the earth, which the Doctor found is almost Newton's language ; he says ' to be to that of water as 9.2, and to
On the Supposition that the Earth is hollow. 295
as 9.5, from which cient to prove the earth a solid body, very considerable mean density, the it would be an interesting communiDoctor says, it may be presumed that cation, were Col. Macdonald to furthe internal parts contain great quan- ' nish us with the exact diameter of the tities of metal. Dr. Hutton's conclu- concavity, and the method of detersion (vide his Mathem. and Philos. mining it. The term “ hollow” is Dict. art. Attraction of Mountains), ambiguous; according to the idea is so very apposite to my present com- which it gives us, the hollow may be munication, that I shall beg to tran- only a foot in diameter, or the earth scribe his own language, and leave the may be a mere shell ; in the latter impartial reader to form his own judg- case, should the venturesome miner ment.
penetrate to the inner part of the crust, “We may therefore be allowed (says the he may possibly get into the magnum Doctor) to admit this law, and to acknow- inane, from which he might not easily ledge that the mean density of the earth is find his way out again! But an intelabout double of that at the surface; and ligent author observes, that, so far, the consequently that the density of the inter- deepest penetrations which avarice has NAL PARTS of the earth is much greater made in the globe of the earth, are no than near the surface. Hence also the more than the punctures made by the whole quantity of matter in the earth will proboscis of a knat on the body of an be at least as great again as if it had been elephant. all composed of matter of the same density Col. Macdonald has been at some with that at the surface, or will be about 4 pains to prove that the original mean, posed of water. This conclusion is totally ing of Gen. i. 2, implies that the earth
is hollow; but Moses there describes contrary to the hypothesis of some natu
the earth in its chaotic state; and, ralists, who suppose the earth to be only a large hollow shell; supporting itself from therefore, admitting that “'David the property of an arch, with an immense Levy.” is correct in rendering the exvacuity in the midst of it. But were that pression “void and empty," I do not the case, the attractions of mountains, and see how we can infer from it that the even smaller irregularities in the earth's carth was hollow, after “the waters surface, would be very great, contrary to had been gathered together in one experiment, and would affect the measures place, and ihe dry land made to apof the degrees of the meridian much more
pear.” Bp. Patrick (see Mant's Bithan we find they do ; and the variation of ble) expounds the passage to which gravity, in different latitudes, in going from I have alluded thus: "A confused the equator to the poles, as found by pen- indigested heap, without any order or dulums, would not be near so regular as experiments have shown it to be."
shape; having no beast nor trees, nor
any thing else with which we now Col. Macdonald has informed us, see it adorned.". This appears to be a “that the earth's polar diameter is commonly received opinion. Parkless than ils equatorial by about 27 hurst, in his Greek Lexicon, informs miles.”. Taking the earth's diameter us, that Pythagoras and Plato seem to 7958 miles, we have 230 : 229:: 7958: have borrowed their rau (chaotic 7929, which gives 29 miles for the ex- màtter or atoms) from the inn, or uncess of the equatorial above the polar formed mass, of Moses, Gen. i. 2, diameter. Hence the foregoing ratio, whence must also be ultimately dewhich is Newton's, and obtained by duced Ovid's the Theory of Gravity, makes the difference of the earth's diameter only
Rudis indigestaque moles two miles more than that assigned Non bene junctarum discordia semina rerum.” them by Col. Macdonald. I should With respect to the expression in Jike to know the principles from which the 9th verse of the 4th chap. of Ephethe Colonel obtained the difference he sians, to which Col. Macdonald has has given ; I have tried the different adverted in his paper on the Magnetic ratios mentioned by Dr. Horsley in his Poles (page 127, in the Mag. for AuMathematics, and have not met with gust 1826), I have perused Locke on any number that approximates so near the Epistles, Paley's Horæ Paulinæ, in the result to Col. Macdonald's dif- and some other commentators on that ference as that which I have adopted verse, but cannot find that any of them above.
have inferred from it that the earth is If the preceding facts are not suffi. hollow. Poole, in bis Annotations,