nothing actually subsisting is the prototype! Upon this both comment and argument would alike be thrown away: it must speak to every man's mind for itself.

The fundamental axiom of the system here developed is, that all matter is endowed with properties which render it capable of undergoing a series of changes in successive times, and in virtue of laws inherent in its existence, which shall produce all the phenomena of animate and inanimate nature, including those of sensation and intellect. This, in fact, is assumed throughout, and the book itself is merely a series of illustrations or explanations of the successive transformations of the universal firemist' into suns and planets, satellites and comets—and even into plants, animals, and men.

The fire-mist,' or 'nebulous matter of space,' is one of those assumptions on which some ingenious men have occasionally ventured to speculate, when reflecting on the phenomena presented by the telescope; but it is to be remarked that as telescopic power is increased, these faint hazes of light are one after another separated into distinct clusters of stars, whose numbers, and either distances or small relative magnitudes, cause them to assume to our organs such an appearance. Others have resisted this optical separation with the use of such powers as we have yet been able to apply to the purpose; and though possibly we may yet improve our astronomical vision to some extent, it is scarcely possible for the most sanguine amongst us ever to separate many of the nebulæ, the chief of which, indeed, are only revealed to us by the telescope. In fact, it is but an elementary problem to shew a limit to the distance at which a sun of given diameter and intensity would be visible through a telescope of a given construction and power; and it is easy to see that a cluster of these being placed in space, in a given general direction from the earth, the appearance would be nebulous if they were a little beyond that distance, and barely separable at that distance. As, therefore, we invariably find the nebulæ giving way one after another as the power of our instruments becomes improved, the immediate inference that a careful inquirer would draw, would be, that all the nebulæ are of the same character, and that distance and the disposition of the component stars are the only characteristic distinctions between any one nebula and all the others. At any rate, the assumption of the fire-mist' is too gratuitous, and too remote from all analogy to what we see most clearly, to be admitted as the foundation of a system so pregnant with important consequences as those which the author builds upon it. It is not only without any analogy, but contrary to all the analogies of general nature. Nor is the assumption supported by any of the

smaller analogies of nature, but incontrovertibly disproved by many of them; for if it be admitted that there still exists a subtle, all-pervading, elastic æther, the vibrations of which produce the sensation of light, it is still the very reverse of a 'fire-mist' as to temperature-the temperature of space being extremely low instead of extremely high, as is proved by observations on radiation and by other phenomena.

Let us, however, admit this, for the moment, to be a plausible hypothesis. It is to heat that he attributes the repulsive energy of the particles of this fire-mist, by which they were kept diffused in infinite space; and he remarks (p. 30) that

The formation of systems out of this matter implies a change of some kind with regard to the condition of heat. Had this power continued to act with its full original repulsive energy, the process of agglomeration by attraction could not have gone on. We do not know enough of the laws of heat to enable us to surmise how the necessary change in this respect was brought about, but we can trace some of the steps and consequences of this process.'

Now here comes another assumption-that a change took place in the condition of heat,' a change for which he can give no reason, and of which he admits we have no conception or even power of surmise. He passes over it, however, as a matter of no consequence; the hypothesis answers his purpose, and is assumed, like the former, without scruple. The facts which he quotes, as steps and consequences' too, are many of them at best very doubtful, and some are certainly incorrect. However, this is not the question-it rather becomes one of whether his solution is adequate, and whether it is the only consistent one. Both these conditions are essential to establish a theory.

He remarks (p. 12) that

Of nebulous matter we know too little to enable us to suggest how nuclei should be established in it. But, supposing that, from a peculiarity in its constitution, nuclei are formed, we know very well how, by virtue of the law of gravitation, the process of an aggregation of the neighbouring matter to those nuclei should proceed, until masses more or less solid should become detached from the rest. It is a well-known law in physics that, when fluid matter collects towards or meets in a centre, it establishes a rotatory motion. See minor results of this law in the whirlwind and the whirlpool-nay, on so humble a scale as the water sinking through the aperture of a funnel. It thus becomes certain that when we arrive at the stage of a nebulous star, we have a rotation on an axis commenced.'

Now, if we admit his fire-mist, his nuclei, and his changed condition of heat, still this passage in itself furnishes the most

complete refutation of his entire system; for upon his system of cosmogony depends, as a basis, his system of vegetable and animal development.

In the first place, it does not by any means follow that the process of aggregation should detach certain masses from the rest in any other sense than by a slight increase of distance between some and a closer approximation of others. This, however, is of little consequence; and it is to the bold and unauthorized assumption that gravitation tends to produce rotatory motion of the aggregated mass that we direct the attention of the reader. Nothing in physical science can be clearer than the fallacy of this assumption. It is contrary to the fundamental idea of gravitation-it is contrary to the known laws of terrestrial motion. As well might he tell us that a perfect balance would tend of itself to move about its fulcrum, or that a falling stone in a uniform medium would deviate from its assigned vertical course! The gravitating power would indeed compress the particles of matter, but its tendency and entire action is towards the nucleus; it compresses them no more on one side of the line of their direction to the centre of force than on every other side: and hence no lateral motion could ensue, and hence, again, no rotatory motion. Rotation, therefore, is yet unaccounted for; and, as necessarily follows from the doctrine of motion, it must owe its origin to a distinct cause, separate from, and independent of, gravitation.

It is true that, if any new force distinct from gravitation act upon the aggregate body in a direction not passing through its own physical centre, rotation will be induced; but this will be, by the nature of the supposed physical system, a force altogether distinct from gravitation, and it does not, in any way, therefore subserve his hypothesis to call in such aid. He quotes, indeed, as a well-known law in physics, that when fluid matter collects towards or meets in a centre, it establishes a rotatory motion.' Now we confess our entire ignorance of this law, as a fact; and even did it exist, it would in nowise follow that it resulted from the impress of a single force tending to one centre from all points without that centre. The cases which he has quoted as illustrations are evidently, to his own mind, the proofs of the law; and he is obviously so entirely unacquainted with the fundamental principles of mechanical philosophy as to not see the extreme disconnection between his proposition and its demonstration. It may be as well to remark, however, upon his whirlpool, whirlwind, and funnel illustrations, that it is to the inequality of force, and want of direct concentricity of direction, of the water and the wind that rotation is due. In all the cases there are different quantities pressing towards the same general region

of space, and commonly with different velocities, thus giving different momenta in each direction; and, besides, they do not in such cases converge accurately towards the same point of space, but to points at different degrees of contiguity to it. The result is what a knowledge of the facts would enable us to predict; and it manifests a singular degree of temerity in any writer to discuss subjects so august, and so transcendently difficult of solution, with such an entire ignorance of the most elementary principles of physics as this speculatist has ventured to do. Let us, however, proceed to his next stage (p. 13), where, having seen how the central bodies of the system were created, we shall discover his process for making planets and their satellites.

Now mechanical philosophy informs us that the instant a mass begins to rotate there is generated a tendency to fling off its outer portions - in other words, the law of centrifugal force begins to operate. There are, then, two forces acting in opposition to each other, the one attracting to, the other throwing from, the centre. While these remain exactly counterpoised, the mass necessarily continues entire; but the least excess of the centrifugal over the attractive force would be attended with the effect of separating the mass and its outward parts. These outer parts would then be left as a ring round the central body, which ring would continue to revolve with the velocity possessed by the central mass at the moment of separation, but not necessarily participating in any changes afterwards undergone by that body. This is a process which might be repeated as soon as a new excess arose in the centrifugal over the attractive forces working in the parent mass. It might indeed continue to be repeated until the mass attained the ultimate limits of the condensation which its constitution imposed upon it. From what cause might arise the periodical occurrence of an excess of the centrifugal force? If we suppose the agglomeration of a nebulous mass to be a process attended by refrigeration or cooling, which many facts render likely, we can easily understand why the outer parts, hardening under this process, might, by virtue of their greater solidity thence acquired, begin to present some resistance to the attractive force. As the solidification proceeded, this resistance would become greater, though there would still be a tendency to adhere. Meanwhile the condensation of the central mass would be going on, tending to produce a separation from what may now be termed the solidifying crust. During the contention between the attractions of these two bodies, or parts of one body, there would probably be a ring of attenuation between the mass and its crust. At length, when the central mass had reached a certain stage in its advance towards solidification, a separation would take place, and the crust would become a detached ring. It is clear, of course, that some law presiding over the refrigeration of heated gaseous bodies would determine the stages at which rings were thus formed and detached. We do not know any such law, but what we have seen assures us it is one observing and reducible to mathematical formulæ.

If these rings consisted of matter nearly uniform throughout, they would probably continue each in its original form; but there are many chances against their being uniform in constitution. The unavoidable effects of irregularity in their constitution would be to cause them to gather towards centres of superior solidity, by which the annular form would, of course, be destroyed. The ring would, in short, break into several masses, the largest of which would be likely to attract the lesser into itself. The whole mass would then necessarily settle into a spherical form by virtue of the law of gravitation; in short, would then become a planet revolving round the sun. Its rotatory motion would, of course, continue, and satellites might then be thrown off in turn from its body in exactly the same way as the primary planets had been thrown off from the sun.'

Such is the form in which the author developes his natural history' of this portion of creation.

The first thing that strikes us in connection with this, is, that the single force of gravitation, by producing also a rotatory one, has at the same time produced a force antagonistic to itself-the centrifugal! We see this antagonist-force acting in opposition till the two are exactly counterpoised, the original force itself still continuing its effects and producing its phenomena, as though the other and opposing force had not existed! Presently they divide the matter between them, and each governs his own share of the divided empire! Then a new antagonist to the gravitating force springs out of the elements of his kingdom in the form of a new centrifugal force, and after another contest gravitation loses another province ! Thus it goes on, till no further dismemberment is compatible with the conditions imposed upon the constitution' of the state! After this, these separate little states are again dismembered by the discordant forces generated within them by this apple of discord' rotation,-the planets have their satellites thrown off! Such is the harmony of the universe as developed by this author; such is his scheme of providence, and his proof of the wisdom and foresight of the Great Creator!

However, discarding analogies of this kind, as being better suited to such philosophy as his than to the philosophy of Newton, let us look at the hypothesis in connection with the principles of motion which are presumed in all physical reasonings, and which are admitted by the author.

We have already pointed out the absurdity of his assuming the production of rotatory motion as the result of the action of gravity but suppose for the moment the possibility of such an origin for rotation, the subsequent portions of his hypothesis would be untenable and impossible.

It is well known that the effect of such revolution as he assumes, taken in connection with gravitation, is, not to produce rings, but envelopes of equal density (infinitesimal in thickness)

VOL. I. NO. V.

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