The grand requirement of the system—power to work the engine—can never be raised by La Place's, nor by any other mechanical plan. The cooling cloud of fire-mist is simply a very big machine, and no machine can generate power to work itself. If La Place could have somehow or other got power for the motion of rotation outside of his cloud, he might have made it revolve, and scatter off great lumps of the lightest outside stuffs, as your grindstone scatters off drops of water when you turn it rapidly; but, having no such power, his theory is a plan to make the grindstone turn itself. It is, therefore, precisely of the same value as any one of the hundred of ingenious schemes for creating power by machinery, of the perpetual motion men, in defiance of the first law of mechanics, that action and reaction are equal.
Moreover, he proposes to raise the power by making the gas cool at one part of the surface faster than at another, and so to make a vortex around that spot, which would set the whole mass to revolving. But no conceivable reason can be alleged why the homogeneous mass should begin to cool at one place faster than another, or indeed why an eternally hot mass should ever begin to cool at all. But, letting that pass, to make the required vortex for the rotation of the whole mass, it should not begin to cool at any part of the surface, but at the center, where, as every engine driver who ever saw a condenser, and every woman who ever cooled a dish of mush knows, it could not possibly begin to cool till the outside mass had become cold; and so no motion could be produced. This is so well known in the machine shops that it is rare to find a machinist own the theory.
But even a more fatal objection has been raised by one of the most eloquent expounders of the theory. Mr. Spencer shows us that the mass, condensing under the influence of gravitation, so far from cooling must necessarily evolve heat. He is perfectly clear and decided on this matter, that the condensing mass could never, by any possibility, begin to cool, but must begin to heat, and go on heating till it burst out in a blaze. He says: "Heat must inevitably be generated by the aggregation of diffused matter into a concrete form; and throughout our reasonings we have assumed that such generation of heat has been an accompaniment of nebular condensation."[202] "While the condensation and the rate of rotation are progressively increasing, the approach of the atoms necessarily generates a progressively increasing temperature. As this temperature rises light begins to be evolved, and ultimately there results a revolving sphere of fluid matter radiating intense light and heat—a sun."[203]
This, it will be perceived, is exactly the reverse of the original nebular theory of a cooling globe, or spheroid of homogeneous nebular matter, diffused by intense heat, and cooling down into suns, and moons, and planets. So far as the Spencer system is accepted, it displaces La Place's theory, and the inventor accordingly works out a new theory of his own, and equally inconsistent with known facts and principles. But as Mr. Spencer candidly owns that his scheme can neither generate matter nor force, as we have already seen, it needs no further discussion in this connection.
The fact is simply this, a chemical perpetual motion is as impossible as a mechanical one. The discovery of the convertibility of forces shows this. The development theory of the generation of motion by processes of the self-heating or the self-cooling of the machine, or by chemical actions and reactions, is, in its last analysis, only a big perpetual motion humbug.
Even were the rotation, and the cooling process, to take place, as is supposed, no such results would proceed from these combined operations as the case requires; for, according to the theory, as the cooling and contracting rings revolve in the verge of a vortex of fluid less dense than themselves, one of these two results must take place: either, as is most probable, from their exceeding tenuity, the rings will break at once into fragments, when, instead of flying outward, they will sink toward the center, and, as long as they are heavier than the surrounding fluid, they will stay there; and, as the cooling goes on on the outside, so will the concentration of the heavier matter, till we have one great spheroid, with a solid center, liquid covering, and gaseous atmosphere. A vortex will never make, nor allow to exist beyond its center, planets heavier than the fluid of which it is composed. The other alternative, and the one which La Place selected, was the supposition that the cooling and contracting rings did not at first break up into pieces, but retained their continuity; but, contrary to all experience and reason, he supposed that these cooling rings kept contracting and widening out from the heated mass, at the same time. The only fluid planetary rings which we can examine—those of Saturn—have been closing in on the planet since the days of Huygens, and eventually will be united with the body of the planet. Every boy who has seen a blacksmith hoop a cart-wheel has learned the principle, that a heated ring contracts as it cools, and in doing so presses in upon the mass around which it clings. But, according to this nebular notion, the fire-mist keeps cooling and shrinking up, while the rings, of the very same heat and material, keep cooling faster, and widening out from it; a piece of schismatical behavior without a parallel among solids or fluids, either in heaven or earth, or under the earth.
Plateau's illustration of the mode in which centrifugal force acts in overcoming molecular attraction, has been cited as a demonstration of the truth of the nebular hypothesis. The conditions, however, are entirely different. By means of clock-work he caused a globule of oil to rotate in a mixture of alcohol and water of the same density, thus entirely getting rid of the power of gravitation; and by increasing the velocity he caused it to flatten out into a disc, and finally to project a multitude of minute drops, which continued their revolutions so long as the fluid in which they floated kept revolving by the motion of the rotating spindle, the divergent drops, the central mass, and the surrounding fluid, being all the while of the same density. But the essential conditions of the nebular theory are, that the central mass exert an attraction of gravitation upon all its parts, and therefore be denser than the surrounding ether or empty space, and that the cooling and contracting rings be of a different density from the rest of the mass. Their divergence from the more fluid portion is supposed to arise from their growing denser. And Reclus shows[204] that the divergent drops owe their existence to the expansion, not to the contraction, of the globule of oil. This experiment, then, contradicts the theory, so far as it is applicable.
Plateau himself never adduced this experiment in support of the nebular theory; but having, by way of illustration, spoken of the revolving drops as satellites, and finding that expression misunderstood, he corrected the error in a subsequent paper. He says: "It is clear that this mode of formation is entirely foreign to La Place's cosmogonic hypothesis; therefore we have no idea of deducing from this little experiment, which only refers to the effects of molecular attraction, and not to those of gravitation, any argument in favor of the hypothesis in question; an hypothesis which in other respects we do not adopt."[205]
It was always contrary to the facts of astronomical science. It has accordingly been repudiated by the most eminent astronomers.
Sir John Herschel declares that the appearance of those groups, or clusters, of stars, supposed to be formed by the condensation of nebulæ is quite different from that depicted by this theory, and that no traces of the ring-making process is visible among them. He thus describes the appearances of these groups; exactly the contrary of that demanded by the theory, which he emphatically disclaims, from the presidential chair of the British Association for the Advancement of Science.