either. It will be our business to offer, under each of these heads, a few instances, such as best admit of a popular explication.

I. Amongst proofs of choice, one is, fixing the source. of light and heat in the centre of the system. The sun is ignited and luminous; the planets which move round him, cold and dark. There seems to be no antecedent necessity for this order. The sun might have been an opaque mass; some one, or two, or more, or any, or all the planets, globes of fire. There is nothing in the nature of the heav enly bodies, which requires that those which are stationary should be on fire, that those which move should be cold; for, in fact, comets are bodies on fire,* or at least capable of the most intense heat, yet revolve round a centre; noi does this order obtain between the primary planets and their secondaries, which are all opaque. When we consider, therefore, that the sun is one; that the planets going round it are at least seven;† that it is indifferent to their nature, which are luminous and which are opaque, and also, in what order, with respect to each other, these two kinds of bodies are disposed; we may judge of the improbability of the present arrangement taking place by chance.

If, by way of accounting for the state in which we find the solar system, it be alleged (and this is one amongst the guesses of those who reject an intelligent Creator) that the planets themselves are only cooled or cooling masses, and were once, like the sun, many thousand times hotter than red-hot iron; then it follows, that the sun also himself must be in his progress towards growing cold; which puts an end to the possibility of his having existed, as he is,

* It may be reasonably doubted whether comets are ever absolutely "on fire," and yet some of them, from their near approach to the sun, must certainly be " capable of intense heat." If we conceive the earth's distance from the sun to be divided into 1000 parts, the comet of 1680 was, at one time, not more distant than six of those parts from the sun. From hence Sir I. Newton calculated that it was exposed to a heat which was 2000 times greater than that of a red-hot iron.-Paxton.

The seven planets here alluded to are Mercury, Venus, the Earth, Mars, Jupiter, Saturn, and the Georgium Sidus: we now know that there are four more, Ceres, Pallas, Juno, and Vesta; the first of these was discovered in 1901, the second was observed in March, 1802, the third was not discovered till 1804, nor the last till 1807. Now Dr. Paley's dedication is dated July, 1802; it is very possible, therefore, that this 22d chapter was written before he had heard of Pallas, and even while it was yet doubtful whether Ceres was a comet or a planet. This will explain the reason for his having qualified the expression, and having said "at least seven."

from eternity. This consequence arises out of the hypoth esis with still more certainty, if we make a part of it, what the philosophers who mantain it have usually taught, that the planets were originally masses of matter, struck off in a state of fusion from the body of the sun by the percussion of a comet, or by a shock from some other cause, with which we are not acquainted: for, if these masses, partaking of the nature and substance of the sun's body, have in process of time lost their heat, that body itself, in time likewise, no matter in how much longer time, must lose its heat also, and therefore be incapable of an eternal duration in the state in which we see it, either for the time to come, or the time past.

The preference of the present to any other mode of distributing luminous and opaque bodies, I take to be evident. It requires more astronomy than I am able to lay before the reader, to show, in its particulars, what would be the effect to the system, of a dark body at the centre, and of one of the planets being luminous; but I think it manifest, without either plates or calculation, first, that supposing the necessary proportion of magnitude between the central and the revolving bodies to be preserved, the ignited planet would not be sufficient to illuminate and warm the rest of the system; secondly, that its light and heat would be imparted to the other planets much more irregularly than light and heat are now received from the sun.

(*) II. Another thing, in which a choice appears to be exercised, and in which, amongst the possibilities out of which the choice was to be made, the number of those which were wrong bore an infinite proportion to the number of those which were right, is in what geometricians call the axis of rotation. This matter I will endeavour to explain. The earth, it is well known, is not an exact globe, but an oblate spheroid, something like an orange. Now the axes of rotation, or the diameters upon which such a body may be made to turn round, are as many as can be drawn through its centre to opposite points upon its whole surface: but of these axes none are permanent, except either its shortest diameter, i. e. that which passes through the heart of the orange from the place where the stalk is inserted into it, and which is but one; or its longest diameters, at right angles with the former, which must all terminate in the single circumference which goes round the thickest part of the orange. The shortest diameter is that upon which in fact the earth turns; and it is, as the reader sees, what it ought to be, a permanent axis; where

as, had blind chance, had a casual impulse, had a stroke or push at random, set the earth a-spinning, the odds were infinite, but that they had sent it round upon a wrong axis. And what would have been the consequence? The difference between a permanent axis and another axis is this. When a spheroid in a state of rotatory motion gets upon a permanent axis, it keeps there; it remains steady and faithful to its position; its poles preserve their direction with respect to the plane and to the centre of its orbit: but whilst it turns upon an axis which is not permanent, (and the number of those we have seen infinitely exceeds the number of the other,) it is always liable to shift and vacillate from one axis to another, with a corresponding change in the inclination of its poles. Therefore, if a planet once set off revolving upon any other than its shortest, or one of its longest axis, the poles on its surface would keep perpetually changing, and it never would attain a permanent axis of rotation. The effect of this unfixedness and instability would be, that the equatorial parts of the earth might become the polar, or the polar the equatorial; to the utter destruction of plants and animals, which are not capable of interchanging their situations, but are respectively adapted to their own. As to ourselves, instead of rejoicing in our temperate zone, and annually preparing for the moderate vicissitude, or rather the agreeable succession of seasons which we experience and expect, we might come to be locked up in the ice and darkness of the arctic circle, with bodies neither inured to its [rigors, nor provided with shelter or defence against them. Nor would it be much better, if the trepidation of our pole, taking an opposite course, should place us under the heats of a vertical sun. But if it would fare so ill with the human inhabitant, who can live under greater varieties of latitude than any other animal; still more noxious would this translation of climate have proved to life in the rest of the creation; and most perhaps of all, in plants. The habitable earth, and its beautiful variety, might have been destroyed by a simple mischance in the axis of rotation.*

*The earth being an oblate spheroid, we may suppose it to be cut by a plane passing through A B, Fig. 3, Plate XXXIX, which may represent its axis, and the common section of this plane with the spheroid will be an ellipse like A D BE; of this ellipse A B will be an axis ; and, from the property of the curve, it will also be the shortest line which can be drawn through the centre C. If now the diameter D E be drawn at right angles to A B, it will be the longest line which can be drawn in the ellipse, and it will represent a diameter of the equator. As the plane

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III. All this, however, proceeds upon a supposition of the earth having been formed at first an oblate spheroid There is another supposition; and perhaps our limited information will not enable us to decide between them. The second supposition is, that the earth, being a mixed mass somewhat fluid, took, as it might do, its present form, by the joint action of the mutual gravitation of its parts and its rotatory motion. This, as we have said, is a point in the history of the earth which our observations are not sufficient to determine. For a very small depth below the surface (but extremely small, less, perhaps, than an eightthousandth part, compared with the depth of the centre) we find vestiges of ancient fluidity. But this fluidity must have hundred times farther than we can gone down many penetrate, to enable the earth to take its present oblate form; and whether any traces of this kind exist to that depth, we are ignorant. Calculations were made a few years ago, of the mean density of the earth, by comparing the force of its attraction with the force of attraction of a rock of granite, the bulk of which could be ascertained: and the upshot of the calculation was, that the earth upon an average, through its whole sphere, has twice the density of granite, or about five times that of water. Therefore it cannot be a hollow shell, as some have formerly supposed; nor can its internal parts be occupied by central fire, or by water. The solid parts must greatly exceed the fluid parts; and the probability is, that it is a solid mass throughout, composed of substances more ponderous the deeper we go. Nevertheless, we may conceive the present face of the earth to have originated from the revolution of a sphere, covered by a surface of a compound mixture; the fluid and solid parts separating, as the surface becomes.quiescent. Here then comes in the moderating hand of the Creator. If the water had exceeded its present proportion, even but by a trifling quantity compared with the whole globe, all

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passing through A B is not confined to one situation more than another, DE may represent_any" one of the longest axes of the spheroid," and will, as well as A B, always be a "permanent axis of rotation." if any other cameter, as G H, is taken, the earth could not continue to revolve permanently about it.-Paxton.

+ The "deep St. John," one of the deepest mines in the Hartz, was found by M. Deluc to sink 1359 feet. This was in 1778, and it may, since that time, have been carried lower, but probably not to the depth of the mine of Valenciana in New Spain, the bottom of which, according to Humboldt, is 1681 feet below the surface. Now the diameter of the earth being about 7912 miles, "the eight-thousandth part of the depth o the centre" must be 2611 feet, or nearly half a mile.—Ibid.

the land would have been covered: had there been much less than there is, there would not have been enough to fertilize the continent.* Had the exsiccation been progressive, such as we may suppose to have been produced by an evaporating heat, how came it to stop at the point at which we see it? Why did it not stop sooner; why at all? The mandate of the Deity will account for this; nothing else will.

IV. OF CENTRIPETAL FORCES. By virtue of the simplest law that can be imagined, viz. that a body continues in the state in which it is, whether of motion or rest; and if in motion, goes on in the line in which it was proceeding, and with the same velocity, unless there be some cause for change: by virtue, I say, of this law, it comes to pass (what may appear to be a strange consequence) that cases arise, in which attraction, incessantly drawing a body towards a centre, never brings, nor ever will bring, the body to that centre, but keep it in eternal circulation round it. If it were possible to fire off a cannon ball with a velocity of five miles in a second, and the resistance of the air could be taken away, the cannon ball would forever wheel round the earth, instead of falling down upon it.† This is the principle which sustains the heavenly motions. The Deity, having appointed this law to matter, (than which, as we have said before, no law could be more simple,) has turned it to a wonderful account in constructing planetary systems." The actuating cause in these systems, is an attraction, which varies reciprocally as the square of the distance; that is, at double the distance, has a quarter of the force; at half the distance four times the strength; and so on. Now, concerning this law of variation, we have three things to observe: First; that attraction, for anything we know about it, was just as capable of one law of variation

* Nearly three quarters of the earth's surface are covered by the sea. Now evaporation is proportionate to the surface of the fluid, and consequently a less expanse of waters would not have afforded a sufficient supply of rain, which does not now fall upon the whole, in greater quantities than are required "to fertilize the earth."-Paxton.

† If a body be projected horizontally from a station A, Fig. 6, Plate XXXIX, which is at a certain height, its weight or the force of gravity will draw it towards the earth. It may be supposed to come down, for example, at B. But from the tendency which the body has to con tinue in the state of motion which is communicated to it, it will be carri ed farther before it falls, if it is projected with a greater force. Hence, if this force be increased it may be made to reach C; by a greater increase, it may be carried to D; or even round to A, from whence it originallv set out.-Ibid.