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phrase "universal order," however, we understand it as applying to the parts of nature fitted together or disposed for special purposes, and do not mean that every atom in the universe is exactly adjusted to every other atom in pre-established harmony. The "blind law" of gravitation keeps the atoms related, and when matter is pushed out of one path it must take some other; but it does not matter to gravitation whether atoms lie scattered apart, or are built up into a structure.
The appearances which militate against this unity of design in nature-the seeming breaks, interruptions, and failures, as when a monstrosity is produced, or animals die in the early stages of their existence-are traceable to the nature of things, to the conditions under which all Intelligence must work. If one end of a lever is raised the other will be depressed, whether we wish it or not; if we chisel a statue we must put up with the chippings all work has its necessary concomitants, but the incidental results need not blind us to the success of the design; as Paley says, teeth are contrived to eat with, and not for the purpose of aching.
A full discussion of the subject in this place is not intended. It is sufficient if it is made to appear that the attempt to illustrate the Wisdom and Beneficence of the Almighty, in the circumstances connected with the evolution of living things, is not in its nature absurd.
EVOLUTION IN GENERAL.
EVOLUTION (from "E," out of, and "volvo," to roll) signifies the continuous out-rolling of phenomena from preceding phenomena, as a flower is unfolded from the bud, or a man's character developed from the character of the youth. When we see a man, we know that he has previously been a youth, and before that a child and an infant; we judge also that he may grow older, and we know that he will eventually die. In like manner, we are certain that our furniture consists of wood which previously had the form of trees, which changed their appearance with the seasons, and grew from small to large; and we know that it is slowly decaying, and will sooner or later lose its present coherent shape. This general information, which all men gain concerning the past and future careers of surrounding things, science has extended, and continues unceasingly to extend. To the biography of the individual man it adds an intrauterine biography, beginning with him as a microscopic germ; and it follows out his ultimate changes until it finds his body resolved into the gaseous products of decomposition. In all such changes, what really goes on is a redistribution of matter and motion; not the destruction of either, not the creation of either. When one moving ball strikes another and is brought to rest, it is only because its motion is transferred; or if the
two move on together they share the motion between them, and its total amount is exactly the same as when it all existed in the first ball before the collision. This rule is universal: the forces at any time manifested are linked with those preceding and succeeding them; their amounts are fixed and measurable, and produce fixed and measurable results. Phenomena constitute a chain of connected history, which stretches forwards as well as backwards; and as the present is the outgrowth of the past, so also it contains the seed of the future. The law of Evolution, thus briefly indicated, applies to the whole of nature as far as known to us, and in several departments its truth has long been universally acknowledged. As illustrations of its operation, let us trace it in the departments of astronomy and geology, choosing these because the truths brought under notice will have some relation to the arguments of future chapters.
§ 1. Evolution of the Solar System.
If we think of the solar system as consisting of a fixed central sun, with a score or two of planets and comets repeating their circling motions with undeviating regularity, our conception is inadequate and erroneous. The sun is not fixed, but has a motion round some larger luminary; the comets of the system are not a constant number, but new ones come and go; the planets do not move in perfect ellipses, but in each revolution deviate from their previous path. No cycle is ever exactly repeated, either in the heavens or on the earth; the forces at work are so involved that throughout nature their action and reaction never bring about a complete return to a previous state.
Moreover, in addition to the sun's proper motion, carrying us to new regions, and the perturbations which every planet causes in the motion of every other, there are changes going on in the solar system which can only end in its transformation or its decay. To begin with small matters: the shooting stars, of which several may be seen on every starlight night, and considerable showers on 14th November, 10th August, and other dates, are particles and pieces of solid matter flying through space, and occasionally coming within the influence of the earth's attraction. On entering our atmosphere-which they do at a great speed-the friction hinders their motion, and they grow hot and luminous, as the wheel of a tender gets hot when the brake is put on. When the particles are small they are entirely vaporized, and leave a luminous train behind; when they are larger they sometimes reach the earth undestroyed. In the British Museum is a collection of more than 200 of these "meteoric stones," for the most part small, but several of them weighing many hundredweights, and one of them 3 tons. It appears, then, that at least one of the planets of the solar system is continually receiving slight additions to its bulk, at the expense of meteor-streams, which thereafter must afford less material for the gravitating power of the sun to act upon, while the earth must offer
Calculations made after the magnificent meteor display of November 1866, prove that these little bodies are not scattered uniformly through space, but are collected into groups, some of which stream round the sun in cometary orbits. Adams showed that this very group (of November 1866) had been previously detected by Tempel and
set down as a comet; and the investigations of Signor Schiaparelli, director of the Observatory of Milan, have proved that the August and April meteors also travel round the sun in orbits identically the same with those of recorded comets. Meteor streams must therefore be either the same thing with comets, or must be closely allied to that class of bodies. If they be identical, it is evident that the masses of comets are becoming less through the scattering of their parts upon the surfaces of planets, and so their eventual entire dissipation may be prophesied. Moreover, if we can see forward far enough to detect this new phase for some of the meteoric matter, so also will a backward glance show us that there were phases which preceded the present arrangement. Astronomers find reason to believe that the solar system was once without the November meteors; that those bodies were dragged into it by the planet Uranus in the early part of the Christian era; and that the August meteors, though of higher antiquity, made their first acquaintance with us in a similar way.1 Mr Sorby also, from a study of the microscopical structure of meteorites, has ascertained that the material was at one time in a state of fusion, and that the most remote condition of which we have positive evidence was that of small detached melted globules, the formation of which can only be satisfactorily explained by supposing that their constituents were originally in the state of vapour, as they now exist in the atmosphere of the sun, and condensed on the temperature becoming lower. These "ultimate cosmical particles" afterwards collected into larger masses, which have been variously changed by subsequent action, and broken up by repeated col1 Report of Committee: British Association. 1871.