fessed desiderata and desideranda, which impede our investigation of the wisdom of the Deity in these the grandest of his works, there are to be found, in the phenomena, ascertained circumstances and laws, sufficient to indicate an intellectual agency in three of its principal operations, viz. in choosing, in determining, in regulating; in choosing, out of a boundless variety of suppositions which were equally possible, that which is beneficial; in determining, what, left to itself, had a thousand chances against conveniency, for one in its favour; in regulating subjects, as to quantity and degree, which, by their nature, were unlimited with respect to either. It will be our business to offer, under each of these heads, a few instances, such as best admit of a popular explication.

And what we say of their forms, is true of their motions. Their motions are carried on without any sensible intermediate apparatus; whereby we are cut off from one principal ground of argumentation, analogy. We have nothing wherewith to compare them; no invention, no discovery, no operation or resource of art, which, in this respect, resembles them. Even those things which are made to imitate and represent them, such as orreries, planetaria, celestial globes, &c. bear no I. Amongst proofs of choice, one is, fixing the affinity to them, in the cause and principle by source of light and heat in the centre of the syswhich their motions are actuated. I can assign tem. The sun is ignited and luminous; the for this difference a reason of utility, viz. a reason planets, which move round him, cold and dark. why, though the action of terrestrial bodies upon There seems to be no antecedent necessity for this each other be, in almost all cases, through the in-order. The sun might have been an opaque mass; tervention of solid or fluid substances, yet central attraction does not operate in this manner. It was necessary that the intervals between the planetary orbs should be devoid of any inert matter either fluid or solid, because such an intervening substance would, by its resistance, destroy those very motions, which attraction is employed to preserve. This may be a final cause of the difference; but still the difference destroys the analogy.

Our ignorance, moreover, of the sensitive natures by which other planets are inhabited, necessarily keeps from us the knowledge of numberless utilities, relations, and subserviencies, which we perceive upon our own globe.

After all; the real subject of admiration is, that we understand so much of astronomy as we do. That an animal confined to the surface of one of the planets; bearing a less proportion to it than the smallest microscopic insect does to the plant it lives upon; that this little, busy, inquisitive creature, by the use of senses which were given to it for its domestic necessities, and by means of the assistance of those senses which it has had the art to procure, should have been enabled to observe the whole system of worlds to which its own belongs; the changes of place of the immense globes which compose it; and with such accuracy, as to mark out beforehand the situation in the heavens in which they will be found at any future point of time; and that these bodies, after sailing through regions of void and trackless space, should arrive at the place where they were expected, not within a minute, but within a few seconds of a minute, of the time prefixed and predicted: all this is wonderful, whether we refer our admiration to the constancy of the heavenly motions themselves, or to the perspicacity and precision with which they have been noticed by mankind. Nor is this the whole, nor indeed the chief part, of what astronomy teaches. By bringing reason to bear upon observation, (the acutest reasoning upon the exactest observation,) the astronomer has been able, out of the "mystic dance," and the confusion (for such it is) under which the motions of the heavenly bodies present themselves to the eye of a mere gazer upon the skies, to elicit their order and their real paths.

Our knowledge, therefore, of astronomy is admirable, though imperfect: and, amidst the con

some one, or two, or more, or any, or all, the planets, globes of fire. There is nothing in the nature of the heavenly 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: nor 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, from eternity. This consequence arises out of the hypothesis with still more certainty, if we make a part of it, what the philosophers who maintain 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 mani

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.

fest, without either plates or calculation, first, that | still more noxious would this translation of climate 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 sys tem; 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.

(*) 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 gone down many hundred times farther than we can 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 compar ing the force of its attraction with the force of attraction of a rock of granite, the bulk of which

(*) 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 short-could be ascertained: and the upshot of the calest diameter is that upon which in fact the earth culation was, that the earth upon an average, turns, and it is, as the reader sees, what it ought through its whole sphere, has twice the density to be, a permanent axis; whereas, had blind of granite, or about five times that of water. chance, had a casual impulse, had a stroke or push Therefore it cannot be a hollow shell, as some at random, set the earth a-spinning, the odds were have formerly supposed; nor can its internal infinite, but that they had sent it round upon a parts be occupied by central fire, or by water. wrong axis. And what would have been the The solid parts must greatly exceed the fluid consequence? The difference between a perma-parts; and the probability is, that it is a solid mass nent axis and another axis is this: When a sphe- throughout, composed of substances more ponderroïd in a state of rotatory motion gets upon a per-ous the deeper we go. Nevertheless, we may conmanent 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 axes, 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 nei ther inured to its rigours, 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;

ceive the present face of the earth to have origi nated 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 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, riz, that a body continues in the state in which it is, whe ther 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 conse quence,) 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

these limits bear so small a proportion to the range compared with that of the body at the centre; the of possibilities upon which chance might equally orbits not much inclined to one another; and have cast it, is not, with any appearance of rea- their eccentricity little. In such a system, the son, to be accounted for by any other cause than a grand points are secure. The mean distances and regulation proceeding from a designing mind. | periodic times, upon which depend our temperaBut our next proposition carries the matter some- ture, and the regularity of our year, are constant. what farther. We say, in the third place, that, The eccentricities, it is true, will still vary; but so out of the different laws which lie within the slowly, and to so small an extent, as to produce no limits of admissible laws, the best is made choice inconveniency from fluctuation of temperature and of; that there are advantages in this particular season. The same as to the obliquity of the law which cannot be demonstrated to belong to planes of the orbits. For instance, the inclination any other law; and, concerning some of which, it of the ecliptic to the equator will never change can be demonstrated that they do not belong to above two degrees (out of ninety,) and that will any other. require many thousand years in performing.

(*) 1. Whilst this law prevails between each particle of matter, the united attraction of a sphere, coinposed of that matter, observes the same law. This property of the law is necessary, to render it applicable to a system composed of spheres, but it is a property which belongs to no other law of attraction that is admissible. The law of variation of the united attraction is in no other case the same as the law of attraction of each particle, one case excepted, and that is of the attraction varying directly as the distance; the inconveniency of which law, in other respects, we have already noticed.

It has been rightly also remarked, that, if the great planets, Jupiter and Saturn, had moved in lower spheres, their influences would have had much more effect as to disturbing the planetary motions, than they now have. While they revolve at so great distances from the rest, they act almost equally on the sun and on the inferior planets; which has nearly the same consequences as not acting at all upon either.

If it be said that the planets might have been sent round the sun in exact circles, in which case, no change of distance from the centre taking place, the law of variation of the attracting power would have never come in question, one law would have served as well as another; an answer to the scheme may be drawn from the consideration of these same perturbing forces. The system retaining in other respects its present constitution, though the planets had been at first sent round in exact circular orbits, they could not have kept them; and if the law of attraction had not been what it is, or, at least, if the prevailing law had transgressed the limits above assigned, every evagation would have been fatal: the planet once drawn, as drawn it necessarily must have been, out of its course, would have wandered in endless error.

(*) V. What we have seen in the law of the centripetal force, viz. a choice guided by views of utility, and a choice of one law out of thousands which might equally have taken place, we see no less in the figures of the planetary orbits. It was not enough to fix the law of the centripetal force, though by the wisest choice; for, even under that law, it was still competent to the planets to have moved in paths possessing so great a degree of eccentricity, as, in the course of every revolution. to be brought very near to the sun, and carried away to immense distances from him.

We may follow this regulation somewhat farther, and still more strikingly perceive that it proceeded from a designing mind. A law both admissible and convenient was requisite. In what way is the law of the attracting globes obtained? Astronomical observations and terrestrial experiments show that the attraction of the globes of the system is made up of the attraction of their parts; the attraction of each globe being compounded of the attractions of its parts. Now the admissible and convenient law which exists, could not be obtained in a system of bodies gravitating by the united gravitation of their parts, unless each particle of matter were attracted by a force varying by one particular law, viz. varying inversely as the square of the distance: for, if the action of the particles be according to any other law whatever, the admissible and convenient law, which is adopted, could not be obtained. Here then are clearly shown regulation and design. A law both admissible and convenient was to be obtained: the mode chosen for obtaining that law was by making each particle of matter act. After this choice was made, then farther attention was to be given to each particle of matter, and one, and one only, particular law of action to be assigned to it. No other law would have answered the pur-comets actually move in orbits of this sort: and, pose intended. had the planets done so, instead of going round in orbits nearly circular, the change from one extremity of temperature to another must, in ours at least, have destroyed every animal and plant upon its surface. Now, the distance from the centre at which a planet sets off, and the absolute force of attraction at that distance, being fixed, the figure of its orbit, its being a circle, or nearer to, or farther off from a circle, viz. a rounder or a longer oval, depends upon two things, the velocity with, and the direction in which, the planet is projected. And these, in order to produce a right result, must be both brought within certain narrow limits. One, and only one, velocity, united with one, and only one, direction, will produce a perfect circle. And the velocity must be near to this velocity, and the direction also near to this direction, to produce orbits, such as the planetary

(*) 2. All systems must be liable to perturbations. And, therefore, to guard against these perturbations, or rather to guard against their running to destructive lengths, is perhaps the strongest evidence of care and foresight that can be given. Now, we are able to demonstrate of our law of attraction, what can be demonstrated of no other, and what qualifies the dangers which arise from cross but unavoidable influences; that the action of the parts of our system upon one another will not cause permanently increasing irregularities, but merely periodical or vibratory ones; that is, they will come to a limit, and then go back again. This we can demonstrate only of a system, in which the following properties concur, riz. that the force shall be inversely as the square of the distance; the masses of the revolving bodies small,

The

have been carried to their proper distances, before they were projected.*

orbits are, nearly circular; that is, ellipses with i small eccentricities. The velocity and the direction must both be right. If the velocity be wrong, To conclude: in astronomy, the great thing is no direction will cure the error; if the direction to raise the imagination to the subject, and that be in any considerable degree oblique, no velocity oftentimes in opposition to the impression made will produce the orbit required. Take for exam- upon the senses. An illusion, for example, must ple the attraction of gravity at the surface of the be gotten over, arising from the distance at which earth. The force of that attraction being what we view the heavenly bodies, viz. the apparent it is, out of all the degrees of velocity, swift and slowness of their motions. The moon shall take slow, with which a ball might be shot off, none some hours in getting half a yard from a star would answer the purpose of which we are speak-which it touched. A motion so deliberate, we may ing, but what was nearly that of five miles in a second. If it were less than that, the body would not get round at all, but would come to the ground; if it were in any considerable degree more than that, the body would take one of those eccentric courses, these long ellipses, of which we have noticed the inconveniency. If the velocity reached the rate of seven miles in a second, or went beyond that, the ball would fly off from the earth, and never be heard of more. In like manner with respect to the direction; out of the innumerable angles in which the ball might be sent off (I mean angles formed with a line drawn to the centre,) none would serve but what was nearly a right one: out of the various directions in which the cannon might be pointed, upwards and downwards, every one would fail, but what was exactly or nearly horizontal. The same thing holds true of the planets: of our own amongst the rest. We are entitled therefore to ask, and to urge the question, Why did the projectile velocity and projectile direction of the earth happen to be nearly those which would retain it in a circular form? Why not one of the infinite number of velocities, one of the infinite number of directions, which would have made it approach much nearer to, or recede much farther from, the sun?

think easily guided. But what is the fact? The
moon, in fact, is, all this while, driving through
the heavens, at the rate of considerably more than
two thousand miles in an hour; which is more
than double of that with which a ball is shot off
from the mouth of a cannon.
Yet is this prodi-
gious rapidity as much under government, as if
the planet proceeded ever so slowly, or were con-
ducted in its course inch by inch. It is also diffi-
cult to bring the imagination to conceive (what
yet, to judge tolerably of the matter, it is neces-
sary to conceive) how loose, if we may so express
it, the heavenly bodies are. Enormous globes,
held by nothing, confined by nothing, are turned
into free and boundless space, each to seek its
course by the virtue of an invisible principle;
but a principle, one, common, and the same in
all; and ascertainable. To preserve such bodies
from being lost, from running together in heaps,
from hindering and distracting one another's mo-
tions in a degree inconsistent with any continu-
ing order; h. e. to cause them to form planetary
systems, systems that, when formed, can be up-
held, and most especially, systems accommodated
to the organized and sensitive natures which the
planets sustain, as we know to be the case, where
alone we can know what the case is, upon our

tion, because it can be demonstrated concerning
it, that it requires an adjustment of force, dis-
tance, direction, and velocity, out of the reach of
chance to have produced; an adjustment, in its
view to utility, similar to that which we see in
ten thousand subjects of nature which are nearer
to us, but in power, and in the extent of space
through which that power is exerted, stupendous.

But many of the heavenly bodies, as the sun and fixed stars, are stationary. Their rest must be the effect of an absence or of an equilibrium of attractions. It proves also that a projectile impulse was originally given to some of the heavenly bodies, and not to others. But farther; if attraction act at all distances, there can only be one quiescent centre of gravity in the universe: and all bodies whatever must be approaching this centre, or revolving round it. According to the

The planets going round, all in the same direc-earth: all this requires an intelligent interposition, and all nearly in the same plane, afforded to Buffon a ground for asserting that they had all been shivered from the sun by the same stroke of a comet, and by that stroke projected into their present orbits. Now, beside that this is to attribute to chance the fortunate concurrence of velocity and direction which we have been here noticing, the hypothesis, as I apprehend, is inconsistent with the physical laws by which the heavenly motions are governed. If the planets were struck off from the surface of the sun, they would return to the surface of the sun again. Nor will this difficulty be got rid of, by supposing that the same violent blow which shattered the sun's surface, and separated large fragments from it, pushed the sun himself out of his place; for, the consequence of this would be, that the sun and system of shattered fragments would have a progressive motion, which, indeed, may possibly be the case with our system; but then each frag* If we suppose the matter of the system to be accument would, in every revolution, return to the mulated in the centre by its gravity, no mechanical surface of the sun again. The hypothesis is principles, with the assistance of this power of gravity, also contradicted, by the vast difference which sub-could separate the vast mass into such parts as the sun and planets; and, after carrying them to their different sists between the diameters of the planetary distances, project them in their several directions, preorbits. The distance of Saturn from the sun (to serving still the quality of action, and reaction, or the say nothing of the Georgium Sidus) is nearly state of the centre of gravity of the system. Such an five-and-twenty times that of Mercury; a dispa- exquisite structure of things could only arise from the contrivance and powerful influences of an intelligent, rity, which it seems impossible to reconcile with free, and most potent agent. The same powers, thereBuffon's scheme. Bodies starting from the same fore, which, at present, govern the material universe, place, with whatever difference of direction or and conduct its various motions, are very different from velocity they set off, could not have been found at nothing, or to have disposed it in the admirable form those which were necessary to have produced it from these different distances from the centre, still in which it now proceeds."-Maclaurin's Account of retaining their nearly circular orbits. They must Newton's Philos. p. 407. ed. 3.