Chapter I. The Dawn Of Life.

All things on this earth may be roughly divided into two classes: things which have motion, and things which have not; in other words, things which are living, and things which are dead. The first constitute the animal and vegetable kingdoms, and the mineral kingdom contains all the inanimate class. Motion and life seem at once to be intimately connected; we recognise the vitality of any living thing, animal or vegetable, by its power of motion; whether from place to place, as in an animal, or in simple changes of form or aspect, as in both animal and vegetable.

Yet we must not confound motion and life. We see motion in even the class of inanimate things. Steam will rise in the air, a stone will fall to the ground; both these are instances of motion, yet even a child scarcely considers them as any sign of life. I propose to myself the project of pondering how far life and motion may be assumed to be indeed one and the same element, though they may differ in degree as much or more than a man differs from a jelly-fish. It will be necessary first to think what phases of motion are readily perceptible to our senses, and then to follow up that chain till we approach forms of motion almost as little to be rendered account of to our senses as is the ultimate mystery, life itself. We may at any rate prove that there is a path advancing step by step into the unknown; we may even go along some part of the road, and we may form a just notion as to where that road will ultimately lead us.

I have already instanced the simplest form of motion with which we are acquainted—the falling of a stone or other body towards the earth. This action or motion is so general or, as it were, natural, that countless generations of men had witnessed it and it did not even occur to them to think of rendering a reason for it. Some of the old Greek philosophers gave a feeble consideration to the matter, but did page 2 not or could not follow the question out; and there it rested till an English philosopher, Isaac Newton, had the remembrance of their difficulties brought to his mind by observing an apple fall from a tree, and set himself to think why the apple should fall to the earth, and whether that motion was in the apple or in the earth. The result of long thought and calculation on his part was the ascertained truth that every substance in the universe is attracted, or drawn towards, or seeks to approach every other substance;: and that it will so approach if there be not forces acting in other directions to prevent it. This attraction is called the force of gravitation, or weight-force; and it is so called because it is greater in proportion to the weight and density of the body exercising that attraction.

It is this same force that accounts for the second form of motion that I mentioned—the rising of steam through the air; for the particles of steam are lighter in proportion to their size or bulk than the particles of the air; the particles of the air are, therefore, more forcibly attracted to the earth, and squeeze out of place or force away the steam higher up into the air, i.e., farther away from the earth.

If instead of air we take water for an example, we shall see the same series of motions repeated, for a piece of iron will sink or drop through the water, because iron is heavier or denser, bulk for bulk, than water; and a bubble of air or a piece of cork will rise through water (just as steam does through the air) because both air and cork are lighter or less dense, bulk for bulk, than water. And now, if instead of water we take mercury, which is also a fluid, we shall find that a piece of gold will sink in it, but a piece of iron will float in it; and this again for the same reason, because gold is denser than mercury, and iron is not so dense as mercury.

Here we may learn two things: firstly, that some solids may be less dense than other fluids; and, secondly, that density is after all but a comparative and conditional term, and is proportional to the medium or atmosphere in which, the action takes place, for both iron and gold will sink in water, or drop through the air, yet only one of them will sink in mercury.

We all know that what is called an empty bucket, that is, a bucket full of air, is not so heavy as a bucket full of water, and that this again is not so heavy as a lump of iron the same size, and this lump of iron will not be so heavy as a page 3 bucket full of mercury, nor this again so heavy as a similar mass of gold.

Now the real meaning of the weight or heaviness of all these is simply the greater or less force with which they are attracted towards the earth; that force being in exact proportion to their density as compared with their bulk. For the earth is the great mass towards which all substances on the earth are attracted, and as far as earthly things are considered we may call it the centre of gravitation. It is our greatest and heaviest mass, and hence all earthly things progress or fall towards it when not prevented by other forces or obstacles. It is true that what we call celestial objects have also an attraction for each other and the earth, and for all things on the earth; but distance is also an element in the calculation of gravitation, and the earth is so much nearer that a stone let go at the distance of 1000 or 100,000 feet above the earth is attracted more powerfully by the earth which is near than by the sun which is so far off, though the sun is 1,300,000 times larger than the earth, and its attraction proportionately great.

And the planets and our earth and the sun would all rush together but for their motion in their orbits—a circular motion which they have that counterbalances this attraction or motion of gravitation and keeps them hovering at a distance. What is the secret or cause of this circular or orbital motion may be discovered by another Newton, but it will certainly be found to be but a phase of this universal force of gravitation.

Indeed all motions and conditions seem to be but phases or consequences of phases of this universal law. Next in order to gravitation as generally defined, we might place what is called the attraction of cohesion—an attraction that does not seem quite so dependent on density, and that might be defined as the greater attraction that substances of the same nature have for each other under favourable circumstances than for substances of a dissimilar nature. It is this attraction that causes the homogeneousness or consistency of [unclear: t] metals, or stone, or wood, &c. This attraction gives as its evidence the two qualities known as hardness and tenacity. It may be exemplified by the cutting of a piece of wood or lead with a steel knife, whereas a piece of steel could not be cut with a wooden or leaden knife. The mechanical explanation of this fact is that the particles of steel have a greater attraction of cohesion for each other page 4 than have the particles of wood or lead; the particles of wood or lead may be easily separated, but the particles of steel are separable with difficulty.

This attraction of cohesion may seem to be but a passive or defensive attraction, while gravitation is an active or offensive power; yet the seemingly passive force of cohesion is always really in action, for it must not be forgotten that it is this force which at every instant holds bodies together in resistance to the active force of gravitation which might otherwise cause an indiscriminate mingling of their atoms with those of all the other bodies composing the mass of the earth. And some phases of this form of attraction are palpably active, for under this head may be classed the force of chemical affinity, and the force which produces and guides crystallization.

The force, chemical affinity, bears a very close resemblance to the attraction of cohesion, and may be roughly defined as the attraction which the particles of one clearly defined chemical element or substance have for another of those elements. At present these elements are known to have certain affinities or combining powers with each other, and these attractions or affinities vary in each case, so that an element will leave one with which it is already combined to join another for which it has a greater affinity, and will again leave that, if one for which it has a still greater affinity be presented to it.

And now we come to the force of crystallization, and must give our earnest attention to this force; for we get here the first glimpse of a force or motion that in some of its actions closely resembles life. For we have here introduced defined growth towards a defined form. Crystals are of varying sizes and shapes according to their substance, the same substance generally following fixed and certain rules as to form. The growth of crystals is sometimes so rapid or vivid that with some substances, and a strong magnifying glass, the crystals may be seen forming themselves. In some instances this action of growth might well be mistaken for some part of the action that is seen in vegetable life. On ancient flint implements accretions of iron and manganese have been found which bear more than a casual resemblance to various cryptogamous plants, mosses, lichens, and algæ or seaweed. An example familiar to us all is that of the mosslike appearance of a frozen window-pane, the "moss" being simply water in a state of crystallization.

This last example brings us face to face with another series of forces or attractions; the force by which bodies may be brought to, and held in, any one of the three conditions: the solid, the fluid, and the gaseous—in a word, how water may exist as ice, water, or steam, each of the three conditions giving powers of combination, or altered force, which would not be possible in any other condition. As far as we know, all elements are capable of these conditions under given circumstances, and there is, as just said, a considerable intrinsic difference in the conditions. Fluids seem only compressible with intense force, while solids have a considerable and gases an excessive amount of compressibility. Fluids and solids, again, have the attraction of cohesion, so that solids retain their form, and fluids their equilibrium; yet in gases the force of cohesion seems to be almost, if not altogether, absent. A pound of any solid substance, or a pint of any fluid, would retain their simple appearance in a vacuum; but it would seem that the same measure of gas would permeate and fill up (though in a rarefied or attenuated form) any vacuum however great.

Now, each of these conditions is distinctly defined and separate, and the change from one to another seems to be effected by some form of the most living force we have yet spoken of—heat. And as we consider this force of heat we find it to be as universal as gravitation, every substance having specific, or intrinsic, or self-contained heat, just as it has specific or self-contained weight. And specific heat varies in different bodies just in a similar manner to what specific weight or gravity does. And just as we may not perceive the weight of a body till some displacement occurs which allows the force of gravitation to come into perceptible action, so specific heat may only become manifest or perceptible when certain changes are brought about in the condition of the substance containing it. When heat is thus manifest or active, it does to the evidence of our senses change some substances from the solid into the fluid state, and from that again into the gaseous state, and a deprivation of heat will act in just the reverse direction.

Chemical action or affinity, which has already been spoken of, is very frequently attended by the evolution or absorption of heat, and for the reason already given, i.e., a disturbance in the molecular conditions of elements which makes manifest their specific heat. Chemical action, indeed, is the main source of the heat with which we are acquainted, page 6 for the heat of the sun itself is but the result of chemical action or combustion in or on the sun.

As with the other forms of force or motion or attraction spoken of, heat is but a comparative condition, and our experience of it on this earth has but a very limited range. We may readily imagine a planet or world where the heat was so great that water was only known in a gaseous state, and their rivers might be of molten metal; or, on the other hand, one so cold that ice might be their usual building material, roofed with sheets of hydrogen, an element that we only know in a gaseous state. And any bodily organism of living creatures would have to be proportionately altered; yet there is nothing repugnant to the idea of a similar condition to mind, or soul, or life, call it what we will, existing under the changed circumstances.

And I think this may be taken as a probable solution of the question whether there is life on other planets or worlds; for wherever there exist the forces that we have knowledge of on this earth, there will life follow as a natural consequence.

I spoke just now of combustion. This word simply means chemical action or combination so intense that heat and light result. And in light we have reached almost the last of the series of forces of which we have yet any clear conception. We have seen by now that the word force is to be used in a somewhat different sense from that generally ascribed to it. It is too generally confounded with "strength" or "motion;" yet we see it may be existing where we have only pictured inactivity, or rest, or death. We may see a soldier standing "at ease." He too is resting, yet the muscles of his legs and back are all in action, or the man would fall to the earth. And in speaking of light as a force it might be thought that I was applying a false word. In giving an instance or two of the power of light, we may recognize that it is literally a force.

We know that a plant in comparative darkness will hardly grow, and will at best be but pale and sickly. It is light that gives the green colour to all vegetation, simply because it is the initial force which gives the chemical elements in vegetation the impulse to unite and form healthy green flesh necessary for the plant's full life. Again, light is the force that draws all our photographic pictures. In taking those pictures, where the light falls strongest the chemical salts are destroyed or decomposed; where the light does not fall those salts are left untouched.

It must need force to do this, and light is that force. Light is certainly the initial force of a vast amount of chemical action, and again it seems sometimes to be the consequence of chemical action; as with heat, which is in turn the origin or result of such action. Some time we may have knowledge of latent or specific light as well as of specific heat or specific gravity.

As yet we know but little of the vast force involved in light. George Stephenson said that a railway engine was driven by the rays of bottled sunshine contained in the coals that fed the furnace, and there seems no doubt that he was correct. Coal is the buried vegetation of forests of millions of years ago. The sun shone on those trees and on their leaves and branches day by day in their growth, the light and warmth was effective in working the chemical change that formed their vegetable tissue, and when the trees fell, century by century, their dead bodies contained and preserved the results of this action; this absorbed or latent light and heat lay buried in them, is in them when they are mined and dug up, and when they are put into the fire-box of the engine. The fire is lit, and by combustion, the bottled sunbeams, developed into the form of heat, are transmitted to the water in the boiler, this heat turns the water from fluid into the gaseous state of steam; the steam occupies vastly more space than water, and in endeavouring to get room to spread itself to its natural bulk is allowed to force out a piston, this piston moves a crank which turns the wheel on which the engine rests, and the whole engine moves on.

In this brief story we see what permutations or changes may take place in the same force; now it appears to us as light, now as heat, now as chemical action, now as mechanical motion overcoming the attraction of gravitation. Indeed there seems but one force, and the changes in it are but changes in that they are more clearly perceived by some one of our imperfect senses than by the others.

I have used the words initial force once or twice and shall need to explain this somewhat, for the ultimate purposes of our argument. Initial force, then, is the impulse which once given to matter or force is carried on in the matter or force itself without need for repetition of the original impulse. For instance, the mechanical action involved in the striking of a match is the initial force which gives rise to its combustion, and this combustion may be conveyed to things innumerable without need for any repetition of page 8 mechanical action. With a slight knowledge of chemistry, we may remember where a single drop of sulphuric acid is capable of initializing the same process of combustion.

In some cases the force of crystallization may be initialized in a similar way. A mass of salts may be in a condition ready for crystallization, and continue in that preparatory stage till some tiny initial mechanical impulse, such as even the prick of a needle, is given, when the mass will at once rush into crystals. We all know too that nitro-glycerine may by a slight mechanical force be driven into gas, and possibly a frightful explosion ensue. Any slight amount of one kind of force may, under favourable circumstances, be the initializer of a vastly increased mass of some widely different phase.

And now I will only call attention to one other form of force before endeavouring to show how all these forces, or some combination of them, may have given the initial impulse to the wondrous force of life. This last force to which I shall draw attention is electricity, a force of whose knowledge we are but yet in the infancy; and a force that seems, even as far as our present knowledge goes, to be capable of a considerable number of phases. This is the force by which, to give a simple example, a man's words may be conveyed almost without lapse of time from one place to another (the electric telegraph); it is also the force that causes the attraction of a magnet for iron.

Whether electricity be the cause of some of the various forms of force already named, or simply a resultant of them, is more than can be said at present: it sometimes appears in the one character and sometimes in the other. It seems in this way to add greater strength to the presumption that all force is but some different and convertible phase of some great and ultimate property:—the very property of being or existing; for existence and movement or force are inalienable and interchangeable terms. But be electricity what it may, it is already known that all things are subject to its influence, and that it is therefore presumably as universal and great in its results as gravitation itself.

With all this well weighed and considered—bearing in mind the different possibilities of matter in its known conditions of solid, fluid, and gaseous—bearing in mind the powers of chemical combination and the novel substances engendered thereby—bearing in mind the power of definite form and growth of which the force of crystallisation is an page 9 example—bearing in mind that an initial impulse however slight, once communicated, may give rise to a condition so widely differing from itself that the change is to our present powers utterly inexplicable; and that this condition will be perpetuated as long as there is matter favourably situated to be affected by it—bearing in mind all this, I ask if there is anything very inconceivable in the idea that matter has been so acted upon by some initial impulse that has given rise to the phase of force which we call life, with all its attendant phenomena?

For, after all, what is life? Animated beings may be traced down to a type wherein they seem little more than inert masses of matter—masses of gelatinous substance, or of vegetable growth scarce differing from rust—and with little more than the power of growth or assimilation of similar matter to that of their own substance, which they have in common with many substances that we hold to be but minerals with the chemical properties of cohesion and combination.

To such a view as this the continual objection made is: "Yes, but you never show us what is the initial force by which inanimate matter is endowed with the property of life." To this I can but say: Can we yet explain any initial impulse? And why do you call any matter inanimate? Is not chemical action itself a phase of life, just as we reasonably presume all these other forces to be but phases of some universal ruling principle? And indeed to me there seems a less distance between the crudest forms of living organisms and simple chemical action, than between those same organisms and intellectual man. This difference and progress I shall make an attempt to follow in my next study, the "Dawn of Humanity." And as to the question of defining or pointing out the initial force which institutes the beginning of life, that initial force just as easy or as difficult to point out as any other initial force of which I have spoken: we see the results, and it is a simple matter of comparative result on which we have arbitrarily made the distinction of calling one phenomenon animate action, while we stigmatize the other as inanimate.

Yes: the greater our power of observation, the less do we see to be the distinction between life and death, between force and matter; death (i.e. inanimation) is but hidden life, matter is but hidden force. Change, or rather motion, is the one constant rule of all things; and as our senses grow, page 10 and fresh capacities or organs of sensibility are developed, we shall grasp at higher and still more intangible phenomena. It is not that Nature's workings are so mysterious, but that our own faculties are so small, our own eyesight so dim. Yet if we will carefully consult and ever strive to improve the faculties we have, and follow out and strengthen in our being the perceptions of justice and truth which Nature everywhere shows us, we shall grow to know her better, and to have fuller, stronger sight—we shall be worthy to know more of the at present mysterious meaning of life. When we are so worthy the knowledge cannot be hidden from us, we may become intelligent co-operators in Nature's work; and with power in our eyes and love in our hearts we shall fulfil the poet's golden prophecy, and become in very deed

"the crowning race
Of those that, eye to eye, shall look
On knowledge; under whose command
Is earth and earth's, and in their hand
Is Nature like an open book."