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worse, lest the advances subsequently made should proceed upon feeble and fallacious foundations. Finally, we shall state both with what object, and what, and how, inquiry ought to be made respecting the heavenly bodies.

CHAPTER VI.

That Philosophical Questions about the Heavenly Bodies, even though they go beyond the common Ideas, and be somewhat difficult, ought to be can- : vassed. And there are proposed five Questions about the System itself: whether it be a System? and, supposing it to be so, what is its Centre, what is its Depth, what is its Connection, and what its Distribution of Parts?

AND now, doubtless, we shall be considered by some as disinterring the ashes of old questions, long, as it were, consigned to the dust of the grave; nay, as evoking their very ghosts, and urging them with fresh interrogatories of our own. But since the philosophy, hitherto in vogue, respecting the heavenly bodies, has no solidity; and since this has been always laid down by us as a sacred and invariable rule, that all must abide the new award of a legitimate induction; and since, if perchance some questions are left behind us untouched, so much the less industry and pains will be exerted in collecting the facts upon them, in consequence of its appearing superfluous to inquire into points on which no question has ever been moved: we hold it necessary to take in hand all questions which the universe may anywhere offer to our consideration. Besides, in proportion as we are less assured of our ability to determine questions by the method we pursue, so much the more confidently do we entertain them. For we see how all must end.

not that the portion of matter which has been assigned to the structure of this our world, lying, as it does, under our own observation, should possess a spherical figure. For, necessarily, each of those worlds must have taken some configuration. For allowing that in infinity there can be no central point, yet in the parts of that infinity there may exist a spherical figure, no less in a world, than in a mortar. Democritus, however, excelled only as an analyzer of the world: in dealing with its aggregates and totality, he was inferior even to ordinary philosophers. The opinion of which we are now to speak, which really destroyed and exploded the notion of a system, was that of Heraclides of Pontus, Eephantus and Nicetas of Syracuse, and particularly of Philolaus, also in our age of Gilbertus, and all (except Galileo) who have held that the earth is a planet, moves, and is, as it were, one of the stars. And this idea has solidity thus far, that the planets and single stars, and the countless number which from their distance baffle our vision, and others also unseen by us, from their being not of a luminous but opaque nature, each in its respective orbit and primary tour through that illimitable expanse which we behold, whether of vacant space or of some subtler and almost indiscernible substance, are dispersed and lie about like islands in a vast ocean, and revolve not upon a common centre, but each upon that of its respective orbit, some absolutely, others with some progressive motion of their own centre. There is one very great difficulty in their opinion, namely, that they altogether banish rest, or an immovable point of nature. Now, it seems that, as there are in nature revolving bodies which are borne along in interminable and ceaseless motion, so, on the contrary, there ought to be some body which is quiescent; between which we place the intermeThe first question, then, is, whether there be a diate nature of those which are carried in a system, that is, whether the world, or universal straight-lined path, since motion in a straight frame of things, be a spherical whole, possessing line is suitable to fragments of spheres, and things a centre? or, rather, whether the single globes of exiled, so to speak, from their natural seats, the earth and stars are placed in dispersion, and which move towards orbs homogeneous with each attached, as it were, by its own root, without themselves, in order that, united with these, they a common middle point or centre? The school may either be rotatory or quiescent. But of this of Democritus and Epicurus, it is true, made a question, whether there be a system, a conclusion boast that their authors had "broken down the will be obtained by means of those which relate walls of the world." Yet that, certainly, is not a to and determine the motion of the earth, whether consequence of the tenets maintained by them. the earth revolve or be at rest, and to the matter For Democritus having laid down his notion of of the stars, whether it be solid or igneous! For, matter, or seminal atoms, infinite in number, limited if the earth stands still, and the heavens perform in their properties and powers,-atoms in agitation, a diurnal revolution, undoubtedly it is a system; and from eternity unfixed in any possible struc- but if the earth be rotatory, it is, nevertheless, not ture or position, was not led, in virtue of that absolutely proved that it is not a system, because opinion, to maintain the existence of a number of we may still fix another centre of the system, worlds, distinguished by variety of form, subject such as the sun, or something else. Again, if to birth and dissolution, some better constructed, the orb of the earth alone is crass and solid, it some more loosely coherent, also of embryo seems as if the matter of the universe was aggloworlds, and agglomerations formed between world merated and condensed into that centre: but if and world. But, were all this assumed, it hinders the moon and other planets are found to be also

the supposition of the earth's motion is not new, but, as we have already said, echoed from the ancients; but that of the sun being the centre of the world, and immovably fixed, is entirely new, (if we except the supposed mention of it in an ill translated verse,) and was first promulgated by Copernicus.

composed of crass and solid matter, it seems that | a system with the sun for its centre. And the dense bodies do not unite in any centre, but lie consent of later ages and of antiquity has rather dispersedly, and, so to speak, at random. Finally, anticipated and sanctioned that idea than not. For if in the interstellar spaces we place a vacuum coacervatum, then the several orbs should seem to have round them, first, the envelope of certain subtle effluvia, and then the vacuum. But if these spaces are a plenum, there should seem to be a union of the denser in the centre, and an expulsion of the rarer substances, to the circumference. Now, it contributes materially to science to know the connexions of questions with one another, because under some of them there is found history or inductive matter to furnish their solution, under others none.

A third question follows with respect to the depth of the system, not that any exact measure of it can be taken, but that it may be set down for certain whether the starry heaven is, so to speak, one region, or, as it is commonly expressed, orb, But, granting a system, next comes our second or whether the stars which are denominated fixed, question, What is the centre of the system? For, are higher than the others, in a sort of abysmal if to any of the orbs ought to be assigned the central profound? For it cannot be that they are of equal place, there appear first to be two orbs which pre- height, if we understand this strictly; for the stars sent the character of a middle point or centre- are undoubtedly not arranged as in a plane, having the earth and the sun. In favour of the earth a certain measurable size on a superficies, like there are our senses, an immemorial opinion, and spots or embedded gems, but are entire globes, most of all this circumstance, that as dense bo- large, and lying deep in the profound. Wheredies contract into a narrow, and rare are diffused fore, when they are found of such disproportionate over a wide space, and the area of every circle magnitude, it is by all means requisite that some contracts towards its centre, it seems to follow of of them should come out more than others, either necessity that the contracted part should be placed upwards or downwards; nor can it be that, either at the centre of the world, as the appropriate, and, in the upper or lower part of them, they are joined as it were, the only place for dense bodies. For in one continuous layer. Were this true of certhe sun again this reason makes, that to a body tain portions of the stars, it would be rash to assert whose functions in the system are greatest and it of them in the aggregate, that the stars are not most potent, that place ought to be assigned from higher placed the one than the other; but even which it can best act upon, and diffuse its influ- though this were true, still we can affirm a defined ence over the entire system. To this we may and very perceptible depth or thickness of that add that the sun evidently has as his satellites region which is called the sphere or starry heaven, Venus and Mercury, and, in the opinion of Tycho, containing such projecting points and varieties of also the rest of the planets; so that the sun plainly altitude; for we see, from the apogees and perigees appears to possess the nature, and to perform, in of the planets, that there belongs to their several some instances, the office of a centre. Therefore heavens a certain distinguishable depth through we are brought so much nearer the determination which they mount and descend. But that questhat it is the centre of the universe, which was the tion only regards this point, whether there are assertion of Copernicus. But in the system of stars one above another, as planet above planet, Copernicus there are many and great difficulties: and, as it were, in different orbits? And that first, there is something revolting to belief, in en-again is in like manner collateral to the other quescumbering the earth with three motions, in de- tion, regarding the motion or condition of the taching the sun from the group of planets with earth. For if the stars revolve with a diurnal which it has so many common properties, in intro- motion about the earth, since they are all carried ducing so much immobility into the system of with the like celerity, and, as it were, with the one nature, (particularly by making the stars and sun impulse; and since it is plainly apparent that immovable, the bodies most luminous and spar- each of the planets, as it varies in height or lowkling of any,) in wishing to fasten, as it were, the ness of position, so it also varies in rapidity or moon to the epicycle of the earth, and in some slowness of motion; it is probable that stars, other assumptions which he makes; savouring of equal in the swiftness of their revolution, are the character of a man who thinks nothing of in-placed in one region of ether, of which, although venting any figment at the expense of nature, the thickness or depth may be supposed considerprovided the bowls of haphazard roll well. But if we are to ascribe motion to the earth, it seems more consistent to banish the idea of a system, and of various globes conceived to be distributed over space, according to the idea of those whom we have already mentioned, than to establish such VOL. II.-73

able, still it is not so great as to create a difference in their incitation or celerity, but only such, that through the whole of each region respectively, all the bodies revolve simultaneously, as if fastened with the chain of one common essence, or, at least, with such discrepancy as, by reason of the dis3 C

tance, is not brought within our vision. Now, if the earth moves, the stars may either stand still, (as Copernicus thought,) or, which is far more probable, and was suggested by Gilbertus, they may revolve each in its place round its own centre, without any motion of that centre, (as the earth does, if you divide its diurnal motion from those two supposed motions which Copernicus has superadded to it.) For whichever of these is the fact, it hinders not that there may be stars ranged one above another, till they escape our

vision.

The fourth question relates to the cohesion of the system, or to the substance connecting it. As to the nature and essential properties of that body or thing which is thought to be pure ether, and is interfused between the stars, we shall presently inquire. We shall now speak only of the principle of cohesion in the system. There are three modes of viewing this. For we must either grant a vacuum, or a substance whose parts are in contact, or, lastly, in continuity. Our first inquiry is, whether there is an extent of absolute vacuity or a vacuum coacervatum in the interstellar space, which Gilbertus ably maintained, and which several of the ancients appear to countenance, who supposed that the various orbs were scattered about without any regular system, especially those who declared the bodies of the stars to be compact masses. Such an opinion amounts to this, that all the globes, as well the stars as the earth, consist of solid and dense matter. That they are enveloped, next their surface, with a certain description of bodies, which are so far homogeneous to their respective globes, but nevertheless more thin, feeble, and attenuated, and which are nothing but effluvia or emanations from the globes themselves, such as are vapours and exhalations, and air itself, if compared with earth. That these effluvia reach to a distance not considerable round each several globe, and that the rest of the interval between the globes, which is incomparably the largest part, is a void. Which opinion we may be prepared to adopt by the fact, that the bodies of the stars are visible from such a prodigious distance. For, were the whole of that space full, especially of bodies extremely unequal in their degrees of density and rarity, so great would be the refraction of their rays, that they could not be propagated to our vision, which, if by far the greatest portion of this space were unoccupied, it is consistent to believe they might be. And, indeed, this question seems to depend, in a great measure, on the question which we shall immediately bring forward respecting the substance of the stars, whether it be dense, or subtle, or expanded? For, if their substance be solid, it should certainly seem as if nature were only occupied and in action about these globes, and their boundaries, and had neglected, and, as it were, left fallow the interposed spaces. Wherefore, it is not improba

ble that the globes are, towards their centres, more compact, towards their surface more lax, in their circumambient substances and effluvia grow less substantial still, and finally terminate in a vacuum. On the other hand, if the essence of the stars is subtle and igneous, it will be manifest that the nature of rare is not merely privative, but of itself a powerful and primary element, not less than the nature of solid, and that it exists in force or prevails in the stars, in ether, and in the atmosphere, so that there is need of the hypothesis of a vacuum coacervatum. That question, too, about a vacuum in the interstellar fields, will depend upon another connected with the great principles of nature: whether we must admit a vacuum at all? And this not without modifying it by a distinction: for it is one thing to deny a vacuum absolutely, and another to deny a vacuum coacervatum. For, much more solid reasons may be alleged for a vacuum intermistum being interposed to keep bodies in a certain degree of laxity, than for maintaining a vacuum coacervatum, (or large vacant spaces.) And, not only was that ingenious man, and great mechanician, Hero, sensible of this, but also Democritus and Leucippus, the inventors of the theory of a vacuum, which Aristotle attempts to attack and overthrow by certain logical subtleties. These two most acute and famous philosophers admit a vacuum intermistum in such a manner as to exclude a vacuum coacervatum. For, according to the opinion of Democritus, every vacuum is so limited and circumscribed as not to admit of the separation or disruption of bodies beyond certain limits, no more than it does of their contraction and consolidation. Though, in what has been preserved of the writings of Democritus, this is nowhere propounded explicitly, yet he seems to say this, that bodies, as well as spaces, are infinite, that, otherwise, (that is, if there were in fact infinite space and finite bodies,) bodies would never cohere: therefore, on account of coinfinity of matter and space, a vacuum is necessarily compressed into certain limits; which seems to have been his opinion, truly and accurately understood; in other words, that certain limits must be set to the development or expansion of bodies through the permeating vacuum; not granting a vacuum apart, or space unreplenished with body. But, if there cannot be admitted in the system, a vacuum of the nature of a solution of continuity, yet, seeing there is found in the parts or portions of the system so extreme a diversity of bodies that they seem to be of different races and countries, there arises a second question which relates to the connection of the system; it is this, whether pure ether be one entire or unbroken stream, or whether it consists of a variety of contiguous parts? Now, it is no part of our character to subtilize about words: but, by a contiguous body, we understand one which lies upon, without being

amalgamated with, another body. Nor, again, in the highest heaven it is dispersed into number

less globes, so that in its highest region it seems to migrate, as it were, into the pure empyreum. Meantime, that must not be forgotten which we mentioned a little before, that nature is accustomed to alternate fine gradations and distinct transits in her processes, so that the confines of the first communicate with the second, and of the second with the third. For, in the upper air, after the air has begun to be purified from the effluvia of the earth, and refined by the vicinity of the heavenly bodies, flame searches out its way and struggles into form; as we see in the lower kind of comets, which are of an intermediate nature between the steady and evanescent sidereal nature. And, again, the part of heaven near the sun appears to grow stellescent, and to pass into a starry essence. For those maculæ which are discoverable, by a faithful and careful observation of the sun, are a sort of germ or rudiments of starry matter; and, in the heaven about Jupiter there are also visible complete and perfect stars, though, from their minuteness, invisible without the help of telescopes. And, again, in the upper parts of the starry heaven, from numberless scintillæ in the ether between the fixed stars, (for which other sufficiently unmeaning reasons are given,) the starry essence seems to be more diffused and spread out continuously. But, of these points we shall say more in discussing those questions, which we presently propose to consider, respecting the substance of the stars and the interstellar For, what we now say relates only

do we mean some impenetrable or hard superstratum, such as the astronomers in general mean, but one such as fluids exhibit, in the instance of water floating on the top of quicksilver; oil, of the water; air, of the oil. For, no one can doubt that in the immense expanse of ether there are immense differences in rarity and density, and in many other properties: but granting either, that is, a plenum or vacuum, this may equally be the fact. For, it is sufficiently certain, that not even in the sea itself, the water at the top and at the bottom is of the same consistency and taste; and, in the air, there is extreme difference between the air contiguous to the earth, and the upper air, and yet it is one entire and unbroken liquid body. The question is therefore brought to this point: whether the differences in the tract of pure air, as it were, insinuate themselves in a continuous stream of imperceptible gradations, or are distributed and arranged into defined and conspicuous limits, where bodies are joined in their locality, which could not be amalgamated, even as among us air lies on water. For, to one who considers the matter simply, the whole of that clear and limpid substance in which the globes of the earth and sun are suspended and float, and which, being interposed between those globes, by its quantity and the space which it occupies, exceeds the dimension of the globes, so to speak, innumerable times, is a thing undivided and perfectly united within itself. But, to one who looks into nature more correctly, this will plainly appear, that na-ether. ture is wont to make her way from one locality to questions respecting the connection of the to another, now by steps, anon abruptly by leaps, and then reverses the progression. Otherwise, if any one really looks into the case, there could be no structure, no organized figure, did nature always proceed by imperceptible degrees. Wherefore, this process by gradations may be fitly placed in the intervals between worlds, but not in a world, to the organization of which it is required that things much dissimilar should be severed the one from the other, and yet brought into close contiguity. Thus it is that the air embraces and is in contact with the earth and waters, a body widely different, and yet placed in proximity, not in the order of, first, earth, then vapour or fog, then pure air, but air at once without an intermediate body. And in the air and ether, two substances we usually join with one another, the most conspicuous and thorough diversity of all may be observed, from their quality being more or less susceptible of a starry nature. There appear, therefore, to be three regions most distinctly lying between the earth and the highest point of heaven; that is, the region of the air, the region of the planetary heaven, and the region of the starry it. But, as to the sun, Venus, Mercury, and the heaven. Now, in the lowest region the substance of the stars is not found, it exists in the middle in the form of conglobation into certain orbs, but

system.

A fifth question remains concerning the distribution of the parts of the system, or the order of the heavenly bodies. And granting that there is not a system but only scattered globes, or granting that there is a system, the centre of which is the sun, or even allowing the astronomers to go in quest of some new system, still there remains equally this inquiry: What planet is nearer or more distant from any other planet? and, in like manner, what planet is at a greater or less distance from the earth, or even from the sun? Now, if the system of the ancients is admitted, there seems no reason why we should attach great importance to any new inquiry concerning the four higher heavens, namely, those of the fixed stars, of Saturn, Jupiter, and Mars. For their position and order are testified by the suffrage of all antiquity, and by the absence of any contradictory phenomenon; their modes of revolving also, whence is derived our principal evidence of the relative heights of the heavenly bodies, are adapted to this structure, and nowhere interfere with

moon, even on the principles of the old system, there was some doubt among the ancients; and among the moderns it is still a question, with

respect to Venus and Mercury, which planet is higher than the other? For in favour of the superior height of Venus this reason offers itself, that it moves somewhat more slowly; and of Mercury, that it is fixed at a nearer distance from the sun, whence one should naturally maintain that it ought to be placed next the sun in height. But, as to the moon, no one ever had any doubt that its place was next the earth, though there was a difference of opinion with regard to its approaches to the sun. Nor ought one question relating to the arrangement of the system to escape a serious inquirer into the subject, which is this, whether the planets alternately pass over and pass below one another? which seems to be. authenticated in the case of Venus by elaborate demonstrations of the fact that it is found sometimes placed below the sun, sometimes above it. And, doubtless, also this is an apt question: whether the deflection of the lower planet does not cut the orbit of the higher planet, and enter within its periphery?

There remains our last question concerning the collocation of parts in the system, that is, whether there be several and different centres in the system, and several choral bands, so to speak, moving around them; especially since the earth is affirmed to be the centre of primary motions; since the sun (in the opinion of Tycho) is the centre of secondary motion; and even Jupiter is made, by Galileo, the centre of the inferior and lately discovered motion of certain satellites.

These, then, are the questions which it seems fitting to propose with respect to the celestial system: namely, whether there is a system, and what is its depth, what its connexion, and what is the order of distributing its parts. As to the outermost parts of heaven, and what has been termed the empyrean heaven, we enter into no theories or inquiries. Therefore, what can be known of it can be learned only from inference, not at all by induction. For such inquisition, therefore, there will both be a fitting time, and a specific plan and mode.

As respects the heaven of heavens and pure space, we are bound entirely to stand by, and submit to, revelation. For, as to what has been said by the Platonic school, and lately by Patricius, (in order, forsooth, to exalt themselves to a diviner height in philosophy,) and said not without gross and visionary extravagance, the ravings, as it were, of a disordered mind;-in short, advanced with extreme audacity and no result, like the acones and other dreams of Valentine, these we regard as mere figments. For we are not tamely to submit to the apotheosis of folly, like that of the Emperor Claudius. It is worse than all other evils-the very pestilence and death of intellect to attach reverence to its chi

meras.

CHAPTER VII.

The following are Questions relating to the Substance of the heavenly Bodies; viz. What Species of Substance is that of the heavenly Bodies generally, compared to sublunary Bodies;—the Substance of the interstellar Ether compared to the Body of a Star-the Substance of the Stars themselves compared to one another, and compared to our Fire, and in its proper Essence ;-and whai Specics of Substance is that of the Galaxy, and of the opaque Maculæ visible in the Antarctic Hemisphere? Then the first Query is set forth, Whether there is a diversity of Substance between Bodies celestial and sublunary, and in what it consists?

HAVING finished our inquiries respecting the system, we must now proceed to those which regard the substance, of the heavenly bodies; for it is the substance of the heavenly bodies, and the courses of their motion, that philosophy chiefly seeks to know. Astronomy investigates their real motion itself and its properties-both astronomy and philosophy their influence and effect.

Care ought to be taken, however, accurately to distinguish between astronomy and philosophy: astronomy preferring those hypotheses which are most convenient for shortening the method of calculation; but philosophy those which most approximate to the truth of nature:-further, that, on the one hand, the hypotheses of astronomy do not in any way prejudge truth; and on the other, the positions of philosophy be such as are perfectly tenable upon the phenomena of astronomy. Whereas, on the contrary, the fact now is, that the figments of astronomy have insinuated themselves into philosophy, and perverted it; and the theories of philosophers about the heavenly bodies are reconcilable only to themselves, and in a great measure abandon astronomy, contemplating in general the system of the heavens, but by no means accommodating themselves to particular phenomena and their causes. Thus, while either science, such as we now have them, is a thing superficial and perfunctory, the foot must be planted more vigorously by far on this foundation

that these two sciences, which, by reason of the contracted speculations of men, and the practice of academic teachers, have been habitually disconnected for so many ages, are one and the same thing, and concrete in one body of science.

Therefore we propose it as our first question, Whether or not there is a diversity between the substance of the heavenly bodies and that of this lower orb? For the premature and dogmatical doctrine of Aristotle has created for us only an imaginary heaven, formed of a certain fifth essence, without change, and also without heat, And, waiving for the present any discussion respecting the four elements which this quintes

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