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885
Divine Interference in Planetary Motions.

886 powerful law, by which all nature is held | 1. There cannot be circular motion at together,

| A or P. That a .planet should require twice in one revolution the divine aid, (for the centripetal and centrifugal forces are equal twice in a revolution) would betray such a want of skill, and such deficiency, in the original, as we cannot attribute to an omniscient and omnipotent Being. I acknowledge that some shadow of an argument, but certainly only a shadow, might be raised in favour of the idea of a divine agency; but not upon the ground which Mr. Jenkins has assumed. We know that all bodies put in motion have a tendency to lose it, however slight be the resistance; and if it could be proved, that the ethereal spaces do offer resistance to the moving Let us suppose a planet to have arrived body, then a divine agency would be at, and to set out from, this point with its necessary to keep up the given quantity of due velocity; in the direction of B M A motion. But as the postulatum cannot be we have the motive force at right angles to granted without proof, and our experience the deflective, a position essential to ciroffers none, the argument has very little {cular motion, but with the radius S A weight.

describe the circular arc A M: now since Mr. Jenkins' first argument is founded by prop. 5, the velocity necessary to make upon his four propositions, which may be the body move in A M is that which resolved to this one, viz. that when the cen- would be generated by an uniformly accetrifugal and centripetal forces are equal, lerated motion over į A S; but the real the body must move in a circle; but as velocity at this point is only that which we find that this circular motion does not would be acquired by the uniformly accetake place, there must be some divine lerated motion į LS, as the focal cord of influence exerted, in continuing the planet curvature to the point A, is equal to the in its former elliptical curve.

perameter (see Bridgestones, page 81,) In opposition to this, I say, that in no and, therefore, since there is a difference of part of the orbit can the body be diverted velocity, the body cannot move in the from elliptical to circular motion. For curve A M, but must fall without it, and this purpose, as I shall avoid mathematical move in the direction A B. In a similar investigations, I shall premise the four fol- manner at P describe the circle P K E, lowing propositions, referring to the works with the radius P S, as also the equicurve where the demonstrations are given. 1. circle whose radius is P O. Now, the

That the planets move in ellipses. 2. That velocity necessary for circular motion at P, all curvilineal motion is caused by the is that which would be acquired by unijoint action of two forces, the deflective formly accelerated motion over { S; but and the original motive force; the former the real velocity at P is that which would in the direction of the centre, and the be acquired over ) L S or } P 0, for P O latter in that of the tangent to the curve. | may be proved equal L S; but PO is 3. That in circular motion, the motive force greater than P S, and hence the velocity is must be at right angles to the deflective. too great. Now, these are the only two (For prop. 2 & 3, see dynamics in any points in the curve where the directions of mechanical work.) 4. That the velocity in the motive and deflective forces are suitable any part of a curve, is equal to that which for circular motion. would be generated by an uniformly acce 2. At B and D there is another essential lerated motion over one fourth of the focal for circular motion, viz. the proper velocity. chord of curvature to that part; (See Ro. It might be shewn by demonstration, that bison's Mechanical Philosophy, or Carr's when the body has arrived at this point, Principia, page 107,) and as in the circle, the velocity has reached that which is the focal chord is the diameter, hence the necessary to make it keep the circular arc; velocity required for circular motion is that but observe the position of the moving which would be acquired by the aforesaid forces; they were at right angles before, motion over one half the radius. I shall but now the motive force forms an acute now proceed to render each of these pro | angle with the deflective, and hence the positions apparent.

'path is incurvated, and the body moves

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owards P. At L the centripetal and cen- | upon the observations, and hence it follows; rifugal forces are equal, (Carr's Principia, that time will stamp, and has stamped, page 154,) where Mr. Jenkins expects correctness upon the theory also. circular motion; but this cannot take place, What is this theory? It is a simple law for there is neither the right velocity nor of nature-mutual attraction, or universal direction of the forces. Hence we conclude gravitation. If there had been any interthat no body moving in an ellipse can be ference of the Deity, the results could not diverted from that course, except some have agreed with the observations; but in extraneous force be applied, and, if left to order to reconcile the one with the other, itself, it will move in an ellipse for ever. some allowance must have been required

The second argument of Mr. Jenkins is to be made. But no allowance is necestaken from the disturbances of the planets, sary, and therefore we must conclude, that occasioned by their mutual attraction. the Deity has so skilfully performed his That the mutual attraction of matter must work, that it requires no interference on bave considerable effect upon all the orbits his part to make it perform its various of the planets, is agreed on all sides. In functions. some parts of their orbits the motion is “Questions which occur in this departretarded, the path less incurvated, and the ment of the study, (observes Dr. Robison, body drawn more from the sun; in other in speaking of the disturbances of planetary points, the motion is accelerated, the orbit motions,) are generally of the most delicate more incurvated, and the body drawn nature, and require the most scrupulous nearer the sun; whilst in Venus and Mars attention to a variety of circumstances. It the orbits are turned and looped, presenting is not enough to know the direction and a very curious kind of motion. In the intensity of the disturbing force in every inferior planets, these irregularities are point of a planet's motion, we must be able nearly opposite; that is, the retardations to collect into one aggregate, the minute and accelerations nearly compensate each and almost imperceptible changes that have other in the course of a revolution, and the accumulated through perhaps a long tract overplus shews itself in the retreat of the of time, during which the forces are conLine of the apsides; but in these two tinually changing both in direction and in planets, this retreat is very small; in the intensity, and are frequently combined with planets Earth and Mars, it is greater. others. Few things are more pleasing But in the other superior planets, Jupiter than being able to trace order and harand Saturn, we see this irregularity very mony in the midst of seeming confusion remarkably evinced.

and derangement, No where, in the wide Besides the retreat of the line of the range of speculation, is order: more comapsides of Jupiter, and the precession of pletely effected." that of Saturn, we see also a diminution of All the seeming disorder terminates in the time of a revolution. In the time of a the detection of a class of subordinate revolution of Jupiter, we see a diminution motions which have regular periods of of one hour and a half; in that of Saturn, increase and diminution, never arising to a of seven hours. In the moon, the irregu- magnitude that makes any considerable larities are more striking on account of the change in the simple elliptical motions, double motion. According to Mr. Jen- so that finally, the solar system seems cal. kins' idea, the Deity counterbalances the culated for almost eternal duration, without effects of these disturbances; but we find he sustaining any deviation from its present does not; the irregularities take place, and state, that will be perceived by any besides these effects accumulate, and will at some astronomers. The display of wisdom in future time, should our system be so long in the selection of this law of natural action, duration, change the very face of nature. and in accommodating it to the various

But the question is, Do the effects of circumstances which contribute to this these irregularities, as observed by teles- , duration and constancy, is surely one of copes, agree with the results obtained by the most engaging objects that can attract calculation. In all cases the identification the attention of mankind.

J. S. is complete; and more than this, the phi- Manchester, May 7, 1829. losopher has pointed out to the observer, results which he had never suspected, but which were necessary to be taken into

MEPHITIC GASES IN MINES. account in all his observations. If obser- | MR. EDITOR, vations agree with theory, and these obser- SIR,The compliment Mr. Bakewell has vations are correct, the theory must be so paid me in his communication upon hydro100 ; but time has stamped correctness / gen gas, inserted in the number of your

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valuable work for Sept. col. 812, calls upon / Mr. Bakewell's second mode is, “To me, although not in direct terms, to notice have flexible tubes, one end open at the the positions he has there laid down. I place where the gas might accumulate, the owe it equally to several other gentlemen, other end having an air-pump fixed thereto, who, with great urbanity, as well verbally the working of which would draw out the as in writing, have noticed the “Essays on gas." Were a coal mine similar in its Mephitic Gases in Mines," inserted in the dimensions to an apartment in a house, or Imperial Magazine for 1828, to request even to a large hall, this might be practiyou will add, if they meet your approba cable; but in a mine which extends, taking tion, the following remarks to those you in all its sinuosities, a mile, such an appa. have already published upon that impor. ratus would be totally inefficient. But coal. tant subject. ---Sir, respectfully yours, mines exist where ventilations by stoves King Square, London. Wm. ColdweLL.

extend, taking in all their complicated

| ramifications, ten miles, and even much · Hydrogen gas exists in water, in coal, | greater lengths; the breadth in some comand in a variety of other mineral sub-partments being very great, and in others stances; and in mines, this gas, as has so narrow as merely to permit the passage been already stated in the essays above of a single miner at once. The quantity of mentioned, is frequently detached from its gas which the largest air-pump could, connexion with oxygen in water, by the through Alexible tubes, draw to the foot of affinity of oxygen for divers minerals, and a shaft in such mines as these, would be from coal by subtile exudations, and by comparatively nothing, the heat generated on the decomposition of The third mode which Mr. Bakewell those mineral, animal, and vegetable sub-recommends is, « to have a perpetual stances, which, in mining operations, con- lamp, burning near the roof of the parts in stitute the refuse of a mine. Mr. Bake-work, so as to consume the gas as it issues well gives us three modes of clearing a from the works." The issues of hydrogen mine from this deleterious gas. The first gas from the surrounding substances, and is “by having openings above every part their entrance into a mine, cannot be calcuin work, where danger is apprehended, so lated upon, much less regulated by the as to give free egress to the gas.” I pre- wisdom of man; they are like the winds sume Mr. B. does not recommend these of heaven, or the vapours of the atmo. openings to extend to the earth's surface, sphere; we feel them, but whence they because such openings would involve the come, and why they come, at any precise miner in expenses too heavy for mining period of time, we know not; and their operations to endure; but he recommends coming and going are equally beyond the indentations in the roof of a mine, to a control of mankind. More subtile than height which would receive all the hydro- atmospheric air, and tremendously more gen gas, and thus clear the mine from this active, hydrogen gas is an enemy to be deadly intruder. On this position. I would shunned when felt; but not to be held observe, it is by no means desirable that under discipline, even by miners. Alas! the roof of a working mine should be for the wisdom of man; it may evade, but injured at all, because it is in general one cannot regulate, the tremendous operations of the most arduous tasks the miner has of hydrogen gas in mines. But, without imposed upon him, during the working of this salutary regulation, a perpetual lamp a coal mine, to keep it up; but these per- immediately beneath the roof of a mine, forations would constitute a broken roof, subject to the infection of this gas, would and increase tenfold the danger of its fall, be the most perilous engine which could whereby the works would be ruined, and by any possibility be introduced therein. the miners buried in the ruins. In coal I cannot see how it could do otherwise mines the works proceed daily; therefore than explode the whole volume of hydroday after day these openings would be gen gas, then in that compartment of the called for; and it would require a set of mine, whenever there was a plenum, or an miners for this specific purpose, which approach thereto; and when and how this would create altogether an expense much plenum introduces itself, whether during a too heavy for the proprietors to bear; and night, a day, or in an hour, or a moment, after all, I conceive it is impossible to per- where is the miner who can furnish inforforate the roofs of many coal mines suffi- mation ? ciently high and wide to furnish apertures Mr. Bakewell informs us, that “hydrocapacious enough to receive all the gas gen gas is quite innocent, if brought into which occasionally issues from the parts contact with a blaze, and the oxygen of adjacent into these mines.

atmospheric air in small quantities, and

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under proper management; and the gas | pipe, so fine that the smallest needle would that emits from coal works may, no doubt, plug it up, let this flame be applied to the be brought to give light to those dreary open end of a main pipe, or to a gasomeregions; at any rate, it might all be con- ter; and what is the immediate consesumed in safety; and, indeed, I am told quence? The consequence is similar to it is consumed in some mines.”

what, under the same circumstances, takes Mr. B. here alludes to gas-works, which place in a mine: an explosion ensues; and furnish to the public gas extracted from woe unto those who are within the reach coal, creating a brilliant. light, in private of its tremendous operations ! buildings as well as in public streets, with. I have heard it asserted again and again, out danger; and these are quoted as exam- | by several gentlemen besides Mr. Bakeples to miners; intimating that, instead of well, “that hydrogen gas is consumed in creating danger, perpetual lamps beneath some mines.” But although I have seduthe roof would consume hydrogen gas, lously endeavoured to trace these asserilluminate the mines, and convert these tions to their source, I have never been dreary regions into brilliant habitations. able to go one jot farther than Mr. B. Happy would be such a day! On be- very cautiously does in his essay, viz. I am holding it, how would gratitude to Divine told that this is the case: the where and Providence swell the bosom of the miner. when, I never could to this moment disBut in all gas-works, the first object of the cover. That small jets of gas, issuing engineer is to chain this tremendous lion. through fissures in a stratum of coal then In retorts of iron he is generated, trained being worked, situate in airy places near up in iron tubes, dressed in iron cylinders, the shaft of a mine, are occasionally fired moved from den to den of similar mate- and suffered to burn, even a whole night, rials, and when matured, confined in that and that the miners sometimes light their capacious iron cage denominated a gaso- candles at these flames in the morning, I meter. From this cage, he moves along know perfectly well, because I have seen iron mains and collateral tubes to the them myself; but I always objected to this point of exhibition; and there, through as an abuse on this score, that without minute pores, perspires, in bickering flames, rendering essential service to any one, it brilliances of the most enchanting cast, and unnecessarily filled the mine with annoying far and wide shuts out darkness from his smoke. . But had these jets of gas been amphitheatre. Harmless and innocent be- situated in the interior of the mine, at a neath these iron curbs, if he breathes out distance from the shaft, I should have flame, it is not the flame of destruction, denounced the man who fired them, as but of delight; serene as a lamb, he serves one who endangered his fellow miners his keeper, and thousands flock to gaze without a cause; because, while the burnwith perfect security. Where is the en- ing of these isolated jets would have been gineer who can thus seize upon and con- like a drop to the ocean of gas in a mine, fine this lion amidst his earthly den? Who- they might, and no doubt some of them ever he is, he is the doctor for the miners; would have caused an explosion. I would but if he cannot in the first instance effect travel with great pleasure a considerable this, instead of the physician, he becomes distance to examine a mine wherein hydro. the destroyer. He who can convert this gen gas is consumed effectually, merely to furious lion, this deadly enemy of miners, ascertain the process, and publish it to the into an innocent lamb, and soothe him into | world. a genial friend, is a physician of value be- ! Certain portions of the contents of Mr. yond all estimate; he shall have my best Bakewell's letter are not new. In my thanks, and I doubt not the best thanks of “Essays on Mephitic Gases in Mines," every well-wisher to mankind.

inserted in the Imperial Magazine for 1828, Ilydrogen gas, even in works constructed blowing apparatus and air pumps are recomby first-rate engineers, and conducted by mended, upon a large scale, in columns artisans of the first class, is a substance so 726 to 729; hydrogen gas is described in formidable and destructive, that, through- columns 226 to 230, &c. &c. Sir H. out the whole of the processes to which it Davy's lamps are noted in columns 35, is needful to subject it, the utmost caution 921, &c. From this gentleman, as well is absolutely necessary, in order to prevent as those who have favoured me with comaccidents, some of which might involve in munications upon this subject, I am sorry their action the destruction of both the to differ in opinion; but having one end works and workmen. Instead of treating in view in all my researches and in all I the jet of gas with flame which issues from publish, viz. Truth, this difference will an aperture at the extremity of a small naturally ensue whenever any thing con

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On Newton's Terrestrial Gravitation to the Moon.

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trary to my ideas of the nature and fitness intimate connexion of the earth and moon. of things is advanced;. and in this respect, It seemed not improbable that as the earth I conceive I may claim with men in gene- moved the moon, the law of force which ral, a genial mind. To Mr. Bakewell, affected terrestrial bodies might in like manhowever, I must award his meed of praise. ner affect the moon, and really I gave NewNot one, out of the numerous communi-ton credit for the ingenuity of this verificacations with which I have been favoured, tion. As, however, the moon, like a stone or have seen published since the “Essays on the earth, is not carried round by the on Mephitic Gases in Mines” were in- diurnal motion; and as the combination of serted in the Imperial Magazine, embodies, the same forces which deflect terrestrial in so concise and conspicuous a form, the bodies towards the centre does not apply to subjects on which he writes, as his letter; the moon and planets, I have latterly di. although several others contain all the rected some attention to this stronghold of modes of prevention or cure which he pro- those who still have faith enough to believe poses, and some of them additional modes in principles of attraction, repulsion, and in rich abundance; but, alas! all of these gravitation. I conceive are ineffectual remedies.

I take it for granted that all your readers Many gentlemen understand the nature are familiar with Newton's diagram on this of hydrogen and carbon, also their union subject. It is in the Cyclopedias which you and action, as gases, who have not had the publish, and is put forward with emphasis same opportunities of witnessing the ope- in every elementary book on natural philorations of these gases upon the large scale sophy. I have many objections to it, but I in mines, which they have had of making will at present trouble you with no more than experiments upon them in the small way three, and, for the sake of precision, I will in a laboratory, and, therefore, while they give them in numbered paragraphs. write accurately, as to the gases, they rea 1. Those who consult or remember the son inaccurately as to their operations in diagram, will observe, that Newton draws mines; because they reason by a supposed a curve and a tangent, i.e. two lines conanalogy, while the analogy is by no means verging to a point or o distance, and experfect. Yet, I conceive nothing would panding to indefinite distances. Of course conduce to the dissemination of useful the successive distances between two such knowledge, even upon this subject, more lines would somewhere express any re(except frequent descents into, and per- quired quantity. This then is the entire şonal examinations of mines) than friendly secret. , He wanted 15,736 Rhynland feet, discussions in periodical publications. and of course he could easily find them at

the distance of about half a minute of a

degree, or a minute of time.* He could of OBSERVATIONS ON SIR ISAAC NEWTON's

course have found also any other desired ALLEGED PROOF OF THE EXTENSION

quantity at some other points of the said OF TERRESTRIAL GRAVITATION TO THE

diverging lines. We shall not, I trust, be MOON.

told, that there was any charm or sanctity MR. EDITOR.

in a minute, or half a degree. It is true, the SIR.-Finding by the letters of various per- astrologers say that these divisions of space sons, that my papers in your miscellany and time were given from above to Seth, the excite more attention than I supposed this first astrologer; but I don't believe this age of mawkish poetry and sickly romance legend. It seems, however, that Newton could bestow on such subjects, I feel it found that it accorded for a minute, but he necessary to dislodge the advocates of er- omitted to state that it accords only for a roneous philosophy from their supposed

| minute, and not for a second, nor half a impregnable citadel, in Newton's pretended

minute, nor for a degree, nor an hour. The proof that the Moon falls in its orbit lines do not diverge with the law of falling exactly such quantity as a stone falls at the hodies; and, therefore, as there is no charm earth, distances being duly considered. I in a minute, the coincidence at that single

For as I allege that gravis, weight, or point proves nothing, and the attempt to gravitation, is a mere local effect of the two- make it prove any thing is a sophism. fold motions of the earth or any planet, it 2. The arbitrary relations of the lines in is obviously impossible that any body, like the trigonometrical canon, have, and can the moon, which does not partake of both have, no relation whatever to the equable the earth's motions, should be the analogous physical forces in nature. A versed sine, patient of those motions. I had long considered this coincidence

* In the period there are 39676 minutes of time, and in the space 21500 minutes in 360 degrees.

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