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cork, Mercury's corresponding nearly to that of lead, and the Sun's to that of water.
4. The figures of the Planets. With regard to superficies, we have no mountains on our earth like those of the moon, far less like those of Mercury, which are supposed to be thrice as high as Chimboraco. According to Schroeter, those of Venus are still higher. Taking into view the different densities of these planets, might we not have expected the results of a physical law or of chemical action, if these must be the causes, to have been more uniform or exhibited a greater degree of similarity ? — The general figure is that of an oblate spheroid, and this is ascribed to the law of gravitation, not however without supposing a certain degree of Huidity in the planets at their formation, the assumption of which is plainly gratuitous. No flattening of the poles in Mercury or Venus has yet been detected. If it be alleged that this was not to be expected in Mercury from the slowness of his rotation on his axis, let it be recollected that Venus moves faster than the earth, and that the moon, which resembles Mercury, is somewhat depressed at the poles. Jupiter, whose diurnal motion is much more rapid than that of Mars and the Earth, is more flattened than either ; but Saturn again, the velocity of whose equatorial parts is less than that of Jupiter, is still more depressed. Supposing this to be accounted for by the greater degree of original fluidity, which is only hypothetic, or by the action of his ring diminishing the gravity of these parts, and thus aiding the flattening at the poles,--still, there are astronomers who doubt the justice of our attributing this figure to the laws of gravitation or centrifugal force.*-Connected with the figures of the planets we
• Dr. PALEY,—who endeavours to show that the Earth must have been made an oblate spheroid at the beginning, and that intention as well as wisdom are manifested in fixing the axis through the shortest diameter, that it might be a permanent axis-bas the following statement,—that on supposition of the Earth's having taken its present shape from spinning on its axis, “ its first fluidity (of which vestiges are found only at a very small depth below the surface, less perhaps than an 8000th part compared with the depth of the centre) must have gone down many hundred times farther than we are able to penetrate, to enable the earth to take its present oblate form,”—and " that calculations were made a few years ago of the mean density of the earth, by comparing the force of its a laction with that of a rock of granite the bulk of which could be ascertained, when 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," he proceeds, “ it cannot be a hollow shell, as some have formerly supposed, nor can its internal parts be occupied by central tire or water. The solid parts must greatly exceed the fluid; and the probability is, that it is a solid mass throughout, composed of substances more ponderous the deeper we go.” Even admitting
may mention Jupiter's belts, and Saturn's ring. If the former be, as is thought, the clouds and vapours of the planet thrown into parallel strata by the velocity of his diurnal revolution, we might expect a similar appearance in Saturn, unless it be somehow prevented by the ring. That ring is supposed to be generated by a common law, as a viscid mass thrown off from the planet. Grant it : still, that there should be such a mass was arbitrary, but much more the inequalities which exist upon it, and which we may afterwards see are clearly demonstrative of design.
5. The rotation of the planets, and the times in which it is performed.—The rotation could not, we have seen, be generated by any physical law, and it is too uniform to be ascribed to chance. At the same time the periods of revolution are regulated by no common standard. Mercury, who twinkles like the fixed stars, takes more than twenty-four days to revolve on his axis. The earth performs her revolution in twenty-four hours, Jupiter in nine, and Saturn in ten with some odds.
We might go on to the atmospheres of the planets, some of an astonishing height compared with others,—the strange fact that some planets have a moon or moons which are wanting to others,-the inclination of their axes to the ecliptic, with the varieties which this presents,-the differences between the comets and planets,—the projection of the former into orbits so dissimilar to those of the latter, with all the diversification of matter in our own globe,-the different orders of beings, and their permanent characteristics. But it is enough to have mentioned these, as constituting with the former the confessedly arbitrary arrangements of one minutely defined, and exceedingly diversified, yet harmonious system. The atheist has no principle by which he may account for these things; the theist, while he beholds them, will lift up his eyes and say, “ Even so, Father, for so it seemed good in thy sight.”
When a fact uniformly takes place, which is not originally the result of any physical law, yet is at the same time
in a certain way that its shape was affected by revolving, yet he shows that the moderating hand of the Creator must be taken into view. The above, he tells us, are among the remarks with which he was furnished by the Andrews Professor of Astronomy in the University of Dublin. Not. Theol. pp. 416, 420.
plainly fitted for the accomplishment of a certain definite purpose, it affords a sufficient indication of design.
1. In selecting a few examples from the system of arbitrary arrangements, and it is but a few we can propose to exhibit, let us begin with Relations.
Although the sun had been an opaque body, we have seen he might have held the place of a centre of revolution to the planets, just as the primaries do to their secondaries or moons. That the central body should be luminous, or that the only luminous body should be the largest to occupy the place of a centre, indicates a relation between him and the planets demonstrative of design in the constitution of the system. He was to be the fountain of light, and they the recipients ; and certainly the fountain could not have been more advantageously placed. Nor is the relation of the earth's position to its structure and inhabitants less remarkable. Let gravity and a projected motion be fitly proportioned, and any planet will freely revolve at any assignable distance from the sun. Was it chance, then, or a divine counsel, that placed the earth in its present orbit, so well adapted to its structure, its atmosphere, and its various productions ? Neither its plants nor its animals are the result of its position, yet the latter is so adapted to the former, that the plants vegetate and attain the requisite degree of perfection in the various climates to which they belong,—the animals live and enjoy the happiness suited to their natures,man can exist in all its regions, not only in the temperate zones, but under the line, and within the polar circles. To have been either nearer the sun, or more distant, it must have had an economy entirely different. We judge in the same manner, by analogy, of the rest of the planets.
Advert next to the inclination of the axis about which the rotation of the earth is performed. Instead of being perpendicular to the plane of the ecliptic, it declines in an angle of more than twenty-three degrees. This we have seen could not be owing to any natural cause; but to this must be ascribed the grateful vicissitudes of the seasons, and those varieties in the length of the days, which befit so well the human constitution and the universal diffusion of mankind over the face of the globe. Take away the inclination, the sun would never approach nearer the northern nations than in March or September. Suppose always the same pole turned to the sun, the yariety of seasons and of days would exist; but if the north were the favoured pole, ever directed to the source of light and beat, then the northern nations would always have long days
and the southern short, the former would bask in a continual summer, the latter mourn under the horrors of perpetual winter. Were the inclination to vary, how destructive to health the oscillations or sudden starts of nutation! “ We might be tossed in a moment from the January of Greenland to the June of Abyssinia.”
By the very great inclination of the axis of Venus to the axis of her orbit, her seasons will vary much more than ours, and be much the same at her tropics and poles.
The axis of the earth is much less inclined to that of its orbit, which is plainly an advantage, as she is less able to bear a varied vicissitude of seasons. Does not the large and very dense atmosphere of Mars, shewn by the occultation of the stars near which he passes and by the redness of his light, compensate for the want of heat so requisite, revolving as he does on his axis in nearly the same time with our world, yet at such a distance from the sun that his annual revolution occupies nearly two of our years ? That he feels accordingly the power of the solar heat just as we do, appears from the phenomena which Dr. Herschell has shewn to arise from the melting of his polar ices. This shews the propriety too of the immense atmosphere of Ceres, nearly 700 miles high and very dense near the planet, and of that of Pallas about 470. Jupiter revolves at the vast distance of 346 millions of miles beyond Mars. His axis, however, is so nearly perpendicular to his orbit that he can have no sensible change of seasons, which is manifestly an advantage. “ If his axis were inclined any considerable number of degrees, just so many degrees round each pole would, in their turn, be almost six of our years in darkness and cold. What vast tracts of land would be rendered uninhabitable !" To the inhabitants of that planet the sun will appear about one twenty-eighth part as large as to us. But not to speak of his moons at present, the defect of solar light and heat is compensated by the quick returns of both, since he revolves on his axis in about ten hours. It is highly probable from observations made on his ring, that the axis of Saturn is also nearly perpendicular to his orbit, and that thus the inconvenience of different seasons to that planet
• Before Seproeter's observations she was supposed to perform only 91 rotations during the time of her annual revolution, 225 of our days nearly. On this supposition the strange appearance of the heavens and gysations of the sun to her inhabitants were ingeniously conceived and described. (Old Encycl. three vols. 410.- Astronomy.) But this state of things, so far out of all relation to that of the other planets, has been clearly disproved. We may transfer the idea, however, to other planetary systems, and learn from it how easily their economy could bave been diversified.
is avoided. The great distance of the Georgium Sidus is in like manner compensated by a rapid diurnal rotation like that of Jupiter and Saturn, and an axis very little inclined to the ecliptic. (Brewster's Encycl.
Astronomy.) Do not the facts with regard to the other planets confirm our position as to design in the inclination of the axis of our own ? And do not all the facts, taken together, clearly prove an originally contemplated relation of the planets to the sun, requiring certain adjustments corresponding to their distances ?
The earth might have revolved in an ecliptic orbit although its perihelion, when in fact it approaches nearest the sun, had coincided with the summer of the northern hemisphere—or the apparent approach of the sun to that half of the globe, occasioned by the inclination of its axis ; but then the temperature of the two hemispheres would not have been properly adjusted, the summer of the one had been much hotter than that of the other. We find that it has been so projected at first, that its perihelion, when it passes nearest the sun, coincides with the winter of the northern hemisphere, where the inhabitants are most numerous, and the largest proportion of land exists to require the amelioration of temperature, while the world of waters in the southern hemisphere counterbalances the increase of summer heat in that department of the globe. We perceive here a relation between the motion of the earth in its orbit, and its external conformation connected with the position and undeviating parallelism of its axis. *
On the surface of the globe, how obvious is the relation between the structure of animals and their respective destinations ! To point out one class of examples, - the length of the neck is duly proportioned to the length of the leg, in all birds formed for wading in the waters, in the flamingo, the crane, the stork, the heron, and in all who are for other reasons mounted very high, as the ostrich, &c. But on the other hand, birds with long necks have not always long legs. The
Might we not specify here the phenomenon of the harvest-moon ? In the autumnal months the full moon seems to rise for several nights succes. sively at the time of sunset. “ This is in consequence of her being placed in an orbit considerably inclined to the plane of the equator, and nearly in that of the ecliptic. When in the beginning of Aries, her orbit is so oblique to the horizon that she must appear to rise about the same time as the portion of her orbit through which she passes from west to east will ascend in about a quarter of an hour.” The same thing takes place once every month, but in the constitution of the system, the arrangement is such that it takes place with the full moon during two of the autumnal months, indicating a relation to the fruits of the earth, and the labours of the husbandman.