things are talked of), we must next inquire whether it be the only one of this kind. For Mercury too is sometimes found in conjunction with the sun, like a spot or little eclipse. But those dusky spots which are observed in the antarctic hemisphere, and which are fixed, like the milky way, suggest a greater doubt concerning the existence of opaque globes in the higher parts of the heaven. For that they are caused by the heaven in those places being rare and as it were perforated, is not probable; because such a diminution and as it were privation of a visible object could not affect our sight at so great a distance; since the rest of the body of ether is itself invisible, and can only be distinguished by comparison with the bodies of stars. It would perhaps be more probable to attribute these blacknesses to defect of light, because the stars are fewer in that part of the heaven, as on the other hand in the neighbourhood of the milky way they are more crowded; so that the one place would seem to be continuously luminous, the other interspersed with shadows. For the celestial fires appear to be more joined together in the antarctic hemisphere than in ours; there being larger stars there, but not so many, and greater spaces between. But the report itself concerning those spots is not much to be relied on; at least there has not been enough diligence used in the observation to justify us as yet in drawing any consequences therefrom. A fact which touches the present inquiry nearer is, that there may possibly be other opaque bodies scattered through the ether, which are not seen at all. For the moon herself when new, though the horn and thin rim of the outer circle, as far as the sun's rays touch, strike the sight, is not visible at all in the middle of the disc: that part is not distinguishable in appearance from the rest of the ether; and those wandering stars discovered (if the report may be trusted) about Jupiter by Galileo are lost to our sight in that sea of ether, like so many small and invisible islands; and in like manner also those stars whereof the collection makes the milky way, if they were placed each apart, and not assembled in a crowd, would escape our sight altogether; as likewise many others, that in clear nights, especially in winter, sparkle; besides, those nebulous stars or openings in Præsepe are now resolved by telescopes into a number of distinct stars; nay, and it seems that in the very purest fountain of light (I mean the sun), there is

some reason, on the evidence of these same telescopes, to suspect the existence of spots, opacity, and inequalities. But if there were no other evidence, the very gradation of light among the celestial stars, descending as it does from the most brilliant to those which are obscure and misty, is enough to prove that there may likewise be globes which are completely opaque. For there seems less difference between a nebulous and opaque star than between the brightest star and a nebulous one. But our sight is plainly deceived and circumscribed; for whatever is dispersed in the heaven, and has not great magnitude and likewise a strong and vivid light, is concealed from us, and does not alter the face of the heaven. And let not any unskilful person be astonished if it be made a question whether globes of compact matter can remain pendulous. For both the earth itself floats pendulous in the middle of the surrounding air, which is an exceedingly soft thing; and great masses of watery clouds and stores of hail hang in the regions of the air, whence they are rather forced down than fall of themselves, before they begin to feel the neighbourhood of the earth. Excellently therefore did Gilbert remark, that heavy bodies when removed to a great distance from the earth gradually lose their motion downwards; inasmuch as that motion rises from no other appetite of bodies than that of uniting and collecting themselves to the earth (which is the mass of bodies of the same nature with them), and is confined within the orb of its own virtue. For as for what is said of motion to the earth's centre, it would indeed be a potent kind of Nothing that should draw such great things to it; nor is body acted on except by body. Therefore let this question concerning solid and opaque globes, though new and harsh to vulgar opinions, be admitted; and let there be joined with it the old though still unsettled question, which of the stars emit a primitive light, and from themselves, and which a light derived from the sun? whereof the one seem to be consubstantial with the sun, the other with the moon. And in short, all inquiry concerning the different substance of the stars as compared one with the other, which appears to be multifarious, some stars looking fiery, others leadcoloured, others white, others brilliant, others manifestly and constantly nebulous, I mean to be referred to this seventh ques

1 Gilbert, Physiol. Nova, i, 21.

tion. Another question is, are the stars true fires? a question however which requires some care to understand it rightly. For it is one thing to say, that the stars are true fires; and another thing to say that the stars (admitting them to be true fires) exert all the powers and produce the same effects which common fire does. Nor does this require us to suppose some notional or imaginary fire, retaining the name of fire without its properties. For our fire also, if it were placed in the ether in such a quantity as the stars are, would perform different operations to those which it does here with us; seeing things acquire very different virtues, both from quantity and from relative position or location. For the greater masses, I mean connatural bodies which are collected in such quantity as to bear a due proportion to the sum of the universe, assume cosmical virtues, which are not to be found in the portions of them. Thus the ocean, which is the largest collection of waters, ebbs and flows; whereas pools and lakes do not. In like manner the whole earth hangs suspended; a piece of earth falls. And the relative position of a thing is of great importance in all respects both in the larger and smaller parts, by reason of the contiguity and neighbourhood of friendly or unfriendly bodies. But there must also be a far greater diversity of actions between the fire of the stars and our own, because it varies not only in quantity and relative position, but also to some extent in substance. For the fire of the stars is pure, perfect, and native; whereas our fire is degenerate, like Vulcan thrown from heaven and halting with the fall. For if a man observe it, fire as we have it here is out of its place, trembling, surrounded by contraries, needy, depending for sustenance upon fuel, and fugitive. Whereas in heaven fire exists in its true place, removed from the assault of any contrary body, constant, sustained by itself and things like itself, and performing its proper operations freely and without molestation. And therefore Patricius had no need, in order to preserve the pyramidal form of flame, as it is found with us, to fancy that the upper part of a star, which is turned towards the ether, may be pyramidal, though the lower, which is visible to us, be globular. For that pyramid of flame comes by accident, from the air closing in and crushing it; since the flame, which is fuller in the region of its aliment, is by the hostility of the air insensibly contracted and moulded into the form of a pyramid. Hence flame

is broad at the base and pointed at the apex, smoke on the other hand is pointed at the bottom and broad at the apex, and like a pyramid inverted; because the air receives smoke, but quenches flame. It is natural therefore that flame should with us be pyramidal, and in the heaven globular. In like manner also flame with us is a momentary body, in ether permanent and durable. And yet even with us flame might last and subsist in its own form, if it were not destroyed by the things about it; which is most manifest in the larger flames. For all that part of a flame, which is situated in the midst and surrounded by flame on all sides, perishes not, but remains the same in quantity unextinguished and rising rapidly upwards; whereas at the sides it is troubled, and it is there that extinction commences. The manner whereof (I mean the permanency of the inner flame in a globular figure, and the vanishing and pyramidal form of the outer flame) may be experimentally demonstrated by using flames of two colours. Then again in point of fierceness there may be a great deal of variation between the celestial flame and ours. For the celestial flame unfolds itself freely and calmly, as being at home, whereas our flame, as being a stranger, is pent in and violent and furious. All fire likewise when close packed and imprisoned becomes fiercer. For the rays of celestial flame themselves when they reach the denser and more obstinate bodies, lay aside their gentleness, and become more scorching. Aristotle ought not therefore to have feared the conflagration of Heraclitus for his world, although he had determined the stars to be real fires. This question then may be received according to this explanation. Next comes another question; whether the stars are nourished, and likewise, whether they are increased, diminished, generated, and extinguished. There was one of the ancients indeed who with a plebeian kind of observation thought that the stars are nourished as fire is, and that they feed on the waters and ocean and moisture of the earth, and are repaired by vapours and exhalations. But this opinion does not seem worthy to supply matter for a question. For such vapours are both exhausted long before they reach the heights of the stars, nor is there enough of them to repair the waters and the earth with rains and dews, and withal to refresh so many and great celestial globes; especially as it is evident that the earth and ocean have continued now for many ages without decrease of mois

ture; whereby it seems that no more is drawn out than comes back again. Nor again does the principle of aliment apply to the stars as it does to our fire. For the principle is that wherever anything perishes and departs there likewise something is replaced and assimilated; which kind of assimilation belongs to the region of confusions, and comes of being surrounded by contrary or dissimilar bodies; whereas in the similar and inner mass of the stars nothing of the kind happens, no more than in the bowels of the earth, which themselves also receive no nourishment, but preserve their substance in its identity, not by assimilation. With regard however to the outer borders of the sidereal bodies, the question is rightly asked, whether these remain of one and the same tenor, or whether they prey on the surrounding ether, and likewise infect it? In this sense therefore a question may be put concerning the aliments of the stars. And to this is rightly joined a question as to the augmentations and diminutions of stars in their whole; though the phenomena are very few which can give occasion to this doubt. For in the first place there is no example of the thing, nor anything resembling it among the things found with us, to countenance such a question; seeing that our globe of earth and water does not seem to be liable to any evident or notable augmentation or diminution on the whole, but to preserve its mass and quantity. But the stars (it will be said) appear to our eyes sometimes of a greater, sometimes of a smaller body. True; but that greatness and smallness of a star is due either to distance and vicinity, as in the apogees and perigees of planets, or to the constitution of the medium. Now that which is caused by the constitution of the medium is easily distinguished, because it changes the appearance, not of some one particular star, but of all alike; as we see in winter nights, in hard frost, when the stars appear increased in magnitude, because vapours both rise more sparingly and are harder strained, and the whole body of the air is somewhat condensed, and inclines to the aqueous or crystalline, which shows forms more large. And if there chance to be any particular interposition of vapours between our sight and one particular star, which magnifies its apparent size (as is frequently and manifestly the case with the sun and moon, and may happen with the rest), neither can this appearance deceive; because this change of magnitude does not last, nor does it follow the star or move with the body of it, but the