PART I.] REVIEW.-Deism compared with Christianity. A little Work, entitled, The Peasants of Chamouni, has originated from this narrative. It is intended for the juvenile library, and will doubtless be an agreeable acquisition to the young reader. 136. Deism compared with Christianity; being an Epistolary Correspondence, containing all the principal objections against revealed Religion, with the Answers annexed; in which is shown the insufficiency of the arguments used in support of Infidedelity. By Edward Chichester, M. A. Rector of the Parishes of Culdaff and Cloncha, in the Diocese of Derry. 3 vols. 8vo, 1821. THE unphilosophical presumption of Deism has been, we hope, already exposed by us in vol. xc. pt. ii. p. 615. We are glad, however, to see the Clergy exerting themselves; and though we 627 It much doubt the prudence of raking up again the long-forgotten sophistry of Chubb, Toland, and other phantasmagorists in ratiocination, because it is like administering poison in order to try the effect of the antidote, yet we are bound to respect Mr. Chichester and a large portion of his matter. is properly supported by theological reading, and his style is particularly neat and elegant. We are not favourable, however, to the manner in which Deism is treated. In our opinion it should be strictly philosophical; and we particularly recommend the early lectures of Dr. Wheeler, as most logical and conclusive. The necessity of Christianity being there philosophically exhibited, there is no need of resorting to the superstructure to prove the soundness of the foundation, a circuitous and troublesome mode of de monstration. PHILOSOPHICAL ENQUIRIES. ON THE FIGURE OF THE EARTH, AND ITS SUPPOSED CONNEXION WITH THE VIBRATIONS OF A PENDULUM. BY CAPTAIN WALTER FORMAN, R. N.* As my design in writing this essay will develope itself in the progress of it, I shall not fatigue the reader with a tedious preface. It is the nature of fluids to press equally on all sides, and whenever there is a difference in the gravity of any two portions of a fluid, there must necessarily be a fall on one part and a rise on the other, until the weight of the diminished quantity of heavier particles be exactly balanced by the weight of the increased quantity of lighter particles. Upon this principle, if the earth had been wholly fluid, its centrifugal force would undoubtedly have produced a depression of the poles, and a small extension of the equatorial diameter; but it is not suspected by philosophers that the ocean, in any part, extends to a greater depth than fifteen or, at the utmost, twenty miles; and, as it is easy to prove, by actual experiment, that solids are not subject to this law, so we have no warrant, either in scripture or reason, to suppose that the solid parts of the earth were ever in a fluid state. * Author of "Remarks on the Opinions of Philosophers concerning the true cause of the Rising of the Tides." Reviewed in p. 151. Philosophers nevertheless have long entertained an opinion, that, in consequence of its centrifugal force, the earth has changed its figure from a sphere to an oblate spheriod, depressed at the poles; and my design in writing this essay is to shew that the premises upon which they have founded this opinion, will not warrant any such conclusion. It can hardly be necessary to go about to prove that solids are not effected by pressure in the same manner as fluids, because, if they were, a clod of earth would not stand upon a heap, but would sink down by the pressure of its own weight, in the same manner as water does; and, if the earth had originally been formed in a fluid state, it could not, without changing its nature, have become solid in the course of a few days. Those therefore who hold this opinion, if they mean to be consistent, are bound to maintain that the Deity was under the necessity of creating the earth in a fluid state, in order to give it an oblate spheroidical form; and then, by a subsequent miracle, which is not recorded in the works of the creation, of changing the nature of a great part of it, in order to make it fit for the purpose for which it was designed as if the all powerful Being who created 628 Captain Forman on the created matter, could not have given it what form he pleased, without having recourse to such circuitous means. I am aware that some of our geological writers, in order to reconcile scripture with their theories, have dextrously contrived to lengthen the days of the creation by making the earth move slower upon its axis; but though this sophistry may serve for a while to prop up the system of the geologists, it will not serve the purpose here, because the earth's centrifugal force must have diminished in exact proportion with the diminution of the velocity of its motion on its axis; and as, in consequence, the loss of gravity in the equatorial parts would have been all but nugatory, the difference of the pressure in the different parts of the earth would have been too trifling to have produced any sensible effect. The difference which has been observed in the vibrations of a pendulum in different parts of the world is, I believe, the origin and ground-work of this hypothesis. It is found that a pendulum vibrates slower at the equator than it does in the temperate latitudes, and the Newtonian philosophers account for this by supposing that, as the equatorial parts are removed farther from the centre, their gravity must necessarily be diminished, while the gravity of the poles, by being brought so much nearer the centre, must be proportionably increased. Surely any thinking man who heard this argument, would naturally infer that these philosophers believed that the power of attraction resided in some substance that was fixed in the earth's centre; but no such idea was ever entertained by them. According to them, all matter mutually attracts, and with equal power; and yet they maintain that the mere circumstance of being removed further from the earth's centre, by an accumulation of matter, will diminish the gravity of the equatorial parts, although the power of attraction in the centre is not stronger than it is in those substances with which they are immediately in contact! * In what way do these philosophers account for all substances in a sphere gravi tating towards its centre? Not because the power of attraction is fixed in the centre, for this they will not allow; but because there is a greater quantity of matter, and consequently a greater power of attraction in that * A difference in the centrifugal force must undoubtedly be the cause of a part of this effect; but I cannot help thinking that a difference in the density of the atmosphere is an equally effectual cause; and I am persuaded that if any one who has the opportunity could count the vibrations of a pendulum in a light-house, where the air is highly rarified, he would find that it would vibrate nearly as slow as it does at the equator. direction than in any other; and upon this principle, an accumulation of matter in the equatorial parts, and a diminution of matter in the polar axis, ought to increase the gravity of the equator, and diminish the gravity of the poles. The very ground-work of their hypothesis is, that, in consequence of the centrifugal force taking off a portion of the gravity of the equatorial parts, there must necessarily be a sinking of the poles and an elevation of the equator, in order to restore the equilibrium; and surely, when the equilibrium is restored, the gravity of all parts of the earth ought to be the same:+ so that, unless it can be shewn that the difference in the vibrations of a pendulum is produced by a difference in the state of the atmosphere, this very difference is a demonstrative proof that the earth has not changed its figure; and consequently is a direct confutation of this hypothesis. If we may credit the newspaper reports, Captain Sabine is at this moment employed in measuring the vibrations of a pendulum in different parts of the world, in order to furnish philosophers with the necessary data to enable them to ascertain the true figure of the earth; and I should be glad to learn, from any of these philosophers, in what way they propose to distinguish between the effect, on the vibrations of a pendulum produced by a difference in the centrifugal force, and that which they suppose is occasioned by a change in the earth's figure? The only way by which we can possibly ascertain the quantum of the centrifugal force, as compared with the power of the earth's attraction, is by observing the difference-in the vibrations of a pendulum in different parts of the world; and when two causes are mixed together, both of which are supposed to produce precisely similar effects, though in different degree, I cannot imagine how it can be possible to distinguish between the effects produced by each. The question concerning the earth's figure was formerly considered of such importance, that it was thought advisable by the French Government to send two companies of philosophers to measure the length of two degrees of latitude, one at the equator, and the other under the arctic circle; and it appears by the reports of these philosophers that a degree of latitude near the pole is longer than a degree of latitude at the equator. From these data the Newtonian philosophers have drawn conclusions which they consider as incontestibly proving that their hypothesis is true; but unfortunately, in coming to these conclusions, they have completely lost sight of what ought to be At least upon the principle adopted by the Newtonians, that the elevation of the equator is equal to the depression of the poles. esteemed PART I.] Captain Forman on the Figure of the Earth. esteemed one of the main props of their philosophy, namely, a central attraction: for if they will but allow that all bodies gravitate towards that point in which direction there is the greatest quantity of mat ter, they will immediately perceive the necessity of supposing, with St. Pierre, that the earth must be an oblong spheroid lengthened at the poles, and not an oblate spheroid that is flattened at the poles. If the earth had been a sphere, it is clear that the length of a degree of latitude would have been the same all over the world, because, in that case, equal angles, drawn from the centre, would always mark equal distances on the circumference; and if the earth had subsequently become depressed at the poles and elevated at the equator, the distance of any one point from the nearest pole would have been considerably lessened, while its distance from the equator would have been proportionably increased; so that, if the earth had been an oblate spheroid depressed at the poles, the length of a degree of latitude at the poles would have been less than it is at the equator, and not greater, as appears now to be the case. This appears to me to be so self-evident, that I should hardly have thought it necessary to prove it by a figure, if experience had not convinced me of the difficulty of making even the wisest philosophers comprehend the force of a proposition when their minds are set against it; and that will always be the case, when they are called upon to retract as error what they have formerly held to be sound doctrine. Let PEPE, in the annexed figure, represent the earth, as it was created, a perfect sphere; and p Me the same earth depressed at the poles and elevated at the equator in consequence of its centrifugal force. Now, upon the principle that all bodies gravitate towards the centre, it is clear that a star, which is in the zenith at M, would be just 45o from the zeniths both of the pole and of the equator.* The an It can hardly be necessary to inform the philosophical reader, that, as the stars 629 gle z pm is just equal to the angle z e m, and consequently there must be just as many degrees of latitude between p and M as there are between e and M; but the measured distance between M and P is a great deal less than it is between M and e. If the earth had been a sphere, the distance between M, in the latitude of 45o, and the pole would have been just equal to its distance from the equator; but in the present instance, the same number of degrees of latitude towards the pole are so much shortened (in consequence of the sinking of the pole) as the line M p is shorter than the line MP, while, towards the equator, they are so much lengthened as the line M e is longer than the line M E. The Newtonian philosophers, in direct opposition to the principles which at allother times they acknowledge, have conceived the singular notion that the zenith of every place is directly perpendicular to the earth's surface, but they might, with equal propriety, have supposed that the zenith, on the side of a hill, was also perpendicular to its surface. A plummet suspended by a line will always shew the direction of the zenith, and, if this must necessarily be perpendicular to the surface, why is it not so at the side of a hill? Upon their own principle of universal gravitation, the zenith of every place is directly opposite the point where the power of the earth's attraction is strongest, and if that point be not in the centre, it is at least in that direction where the greatest quantity of matter is to be found. Now, as there is more matter in the direction M C N than there is in the direction M n, which is perpendicular to the surface, it evidently folfows that the zenith M must be at Z, and not at k; and consequently, if the admeasurements of these philosophers can be depended upon, the earth's figure must be directly the reverse of what has heretofore been supposed. I shall here take the liberty of making a few observations upon the principle, by which these philosophers have endeavoured to ascertain the exact length of a degree of latitude in different parts of the world. For my own part, I readily allow that it may be sufficient to enable us to give a near guess at the number of miles comprised within the earth's circumference; but when so nice a calculation is required as the difference in the length of any two degrees of latitude, I do not think that the least de pendence can be placed upon so uncertain a principle. It is acknowledged in a paper lately sent forth by the Astronomical Ŝociety, that our tables of refraction are not to be depended upon in very low altitudes; have no sensible parallax, the direction of the star, both at the pole and the equator, must be parallel to the line M Z. and 630 Captain Forman on the Figure of the Earth. and how a correct trigonometrical survey can be performed, without making allowance for refraction, is beyond my comprehension. The spirit level can be of no service, unless we know what to allow for refraction, and we are informed by the highest philosophical authority, that our tables of refraction are not to be depended upon! Those philosophers, that were sent out to measure the degrees of latitude, either did make allowance for refraction, or they did not. If they did not, their calculations, in both places, must have been erroneous; if they did, as they could only have guessed at the proper quantity, they may not have allowed enough; and, in both cases, as the refraction is always greater in high latitudes than at the equator, a mistake must necessarily have produced a greater error in a high than in a low latitude. If they were right, they could only have been right by chance, and chance is not to be admitted into a mathematical demonstration. My own opinion is, that the earth is a sphere, because, as that figure appears to me to be most convenient, it is most likely that it was so formed at the creation; and the supposed differences in the lengths of the degrees of latitude may fairly be attributed to a mistake in the above-mentioned calculations, owing to the want of a correct table of refractions. I give this however merely as an opinion, for I have no means of proving it; and, as the discovery of truth is the sole object I have in view, I shall not attempt to conceal, that, if the fact may be depended upon, the speroidical appearance of Jupiter, furnishes a powerful argument in opposition to this opinion. If it can be satisfactorily made out that the spheroidical appearance of Jupiter is real, and not the defect of some optical deception, analogy will certainly be in favour of the Newtonian theory; but I contend that all the other premises of these philosophers either prove nothing of the kind, or directly prove the contrary. By their own principles, a change in the earth's fi gure, from a sphere to a spheroid depressed at the poles, instead of increasing, ought to diminish the differences, in the vibrations of a pendulum, that must necessarily be produced by the centrifugal force; and the length of the degrees of latitude, instead of increasing as these philosophers have reported, would have decreased all the way from the equator to the poles. As I have never had an opportunity of measuring the proportions in Jupiter's figure, I shall not presume to give an opinion on the subject, but I know, by my own experience, that, without intending any deceit, we are all very apt to fancy facts which have no existence, whenever these facts are necessary to prop up our hypothesis. Let the figure of Jupiter however be what it may, it does not necessarily follow that the solid parts of the earth must therefore have been created in a fluid state; and if not, the centrifugal force could have had nothing to do with the effect. * If it had been necessary that the earth should have taken the form of an oblate spheroid, the all-powerful Being, who created matter out of nothing, had only to have willed, and it would have taken that or any other form he pleased. The Newtonian philosophers however are determined that the earth shall be indebted for its form to natural means alone, and thus, in order to get rid of a seeming difficulty, they run into a real absurdity. If the solid parts of the earth had ever been in a fluid state, the heaviest substances would naturally have sunk nearest the centre, and yet we always find that lead, gold, and all the heaviest metals, are resting upon substanees that are lighter than themselves. Here no doubt I shall be referred to the systems of the geologists, and told of violent irruptions that have torn the earth up even from its centre. But in spite of all that has been said by the geologists upon this subject, the appearance of the different strata, even as they represent them in their treatises, indicate none of these commotions with which they are so fond of astonishing their readers. Where are the chasms reaching In the biographical sketch of the late Sir William Herschel, which has lately appeared in the Edinburgh Philosophical Journal, it is stated that that eminent philosopher ascertained that the proportion which the polar axis of Mars bore to its equatorial diameter was as 15 to 16. Now the velocity of the centrifugal force in Mars is not more than half what it is in the earth, and yet we are told that the difference in the proportions of our polar and equatorial diameter is only as 289 to 290! Every one surely will allow, that effects are always proportioned to the power that produces them, and, in that case, I shall be glad to be informed in what way a minor power can produce a greater effect? One of two things then is evidently certain, either this supposed spheroidical appearance of Mars is deceptive, and, in that case, we have a right to infer the same in Jupiter's appearance, or their centrifugal forces have nothing to do with the formation of their figures. Again, if we may trust to appearances, Saturn is more flattened at the poles than Jupiter, and yet its centrifugal force is not near so great: but what is still more extraordinary, the late Sir William Herschel discovered that there is a great dissimilarity in the figures of these two planets, which certainly proves, either that these appearances are altogether deceptive, or else that their centrifugal forces have nothing to do with their production, for it is morally impossible that the same cause could produce dissimilar effects. down PART 1] Captain Forman on the down even to the centre, which must have been the necessary consequences of these commotions? Why do the strata, for the most part, always incline in one direction, as if they had been gently lifted up by design, and not torn up by violence? These effects, if necessary, might possibly have been produced by earthquakes; but the same violent commotion that would have been requisite to lift the metals out of their beds, and toss them over those substances, which, in the order of things, must have been so much higher than themselves, would have broke these strata and scattered them in all sorts of directions, and it certainly is not in the nature of things that the chasms, in all parts of the world, have been closed up. The question concerning the true figure of the earth is of very great importance, especially to the Newtonian philosophers; for not only is it interesting in itself, but another of their hypotheses, by which they account for the precession of the equinoxes, solely depends upon this supposed change in the earth's figure. The Newtonian philosophers account for the precession of the equinoxes, by supposing that the accumulation of matter about the equator, which is occasioned by the earth's rotatory motion, is some how or other (for none of their hypotheses is intelligible,) acted upon by the sun's and moon's attraction, by which means the equator is brought "sooner under them" than would otherwise have been the case. "It has already been observed," says Ferguson, "that, by the earth's motion on its axis, there is more matter accumulated all around the equatorial parts than any where else on the earth. The sun and moon, by attracting this redundancy of matter, bring the equator sooner under them, in every return towards it, than if there was no such accumulation." * Now I have already shewn that, with the exception of one analogous case, all the LITERATURE, ROMAN ANTIQUITIES. Some splendid remains of antiquity have been recently discovered in a field, on the estate of W. Greenwood, esq. of Brookwood, in Hampshire. Six tesselated pavements have been already cleared, two of which are of the most intricate and beautiful workmanship; the smallest of these contains representations of eight of the heathen gods (four of which are perfect), round a * Dr. Brewster, in his Supplement to this work, has attempted to explain in what way this is brought about, but I confess that I am unable to comprehend him. premises, upon which the Newtonian philosophers have grounded their hypothesis, directly prove the contrary position; but admitting, for the sake of argument, that there may be an accumulation of matter about the equatorial parts, that fact will not at all assist them in accounting for the precession of the equinoxes. Let any one turn to the foregoing figure, and suppose the sun or moon to be placed in any direction he may think proper, and he will immediately perceive that, in the same proportion that any portion of matter in the earth is brought nearer either of these bodies, a similar portion will be carried further off. The loss of attraction on one side will just equal the increase on the other: the sum of both will be precisely the same, the centre of gravity in the earth will be in the same place, and how, in the name of common sense, can such a change produce any change in the power of the sun or moon's attraction? The only effect that could be produced by a change in the earth's figure, would be a diminution of the angle which the equator makes with the ecleptic, but that would not produce any change either in the places or the times of the equinoxes; which any one may convince himself of, if he will take the pains to represent it on paper by a figure; and consequently the Newtonian philosophers have endeavoured to account for this phenomenon by a cause, the existence of which is very doubtful, and which is altogether inadequate, even if it do exist. SCIENCE, &c. Medusa's head as a centre piece. The larger has a very beautiful octagonal centre piece, representing Hercules and Antæus, and a reclining armed figure extending her hand to the wrestlers. This is surrounded by four large heads and an intricate arrangement of highly-ornamented squares, forming octagons, diamonds, &c. This last room appears to be built on arches, and the hollow beneath it is connected with the upper air by flues at equal distances in the walls. The remainder of the pavements (except a very small mutilated imperfect pattern in a sort of passage) are plain, and very perfect, and composed of bricks about an inch square. Workmen are continually removing the rub |