From some of the criticisms on the First Edition of this work I fear that the distinction I endeavoured to draw between the use of the term “polarity” in the inorganic and in the spiritual worlds has not been made sufficiently clear. I stated in the Introduction “That while the principle of polarity pervades both worlds, I am far from assuming that the laws under which it acts are identical; and that virtue and vice, pain and pleasure, are products of the same mathematical laws as regulate the attractions and repulsions of molecules and atoms.” But this warning has been apparently overlooked by some readers who have assumed that instead of analogy I meant identity, and that it was a mistake to use the same word “polarity” for phenomena so essentially distinct as those of the material and the spiritual worlds.
Thus my “guide, philosopher, and friend,” Professor Huxley, for whose authority I have the highest respect, observed in a recent article, that he had long ago acquired a habit, if he came across the word polarity applied to anything but magnetism and electricity, of throwing down the book and reading no farther. I must confess that I felt a little disconcerted when I read this passage; but I was soon consoled, for, in a month or two afterwards, I came across another passage in the same Review which said, “However revolting may be the accumulation of misery at the negative pole of Society, in contrast with that of monstrous wealth at the positive pole, this state of things must abide and grow continuously worse, as long as Istar (the dual Goddess of the Babylonians) holds her way unchecked.”
Surely, I thought, here is a case in which the Professor must have thrown down the Review when he came to these words: but when I came to the end, I found that it was not the Review, but the pen, which must have been thrown down, for the article is signed “T. Huxley.” Can there be a more conclusive proof that there are a vast variety of facts outside of magnetism and electricity, connected by an underlying idea, which inevitably suggests analogy to them, and which can be most conveniently expressed by the word “polarity”? Words after all are only coins to facilitate the interchange of ideas, and the best word is that which serves the purpose most clearly and concisely. Thus instead of using a waggon load of copper, or the verbiage of a conveyancer’s deed, to express the ideas comprised in such words as “theism,” “pantheism,” or “agnosticism,” we coin them for general use, as Huxley did the word “agnosticism,” in order to convey our meaning.
Polarity is such a word. It sums up what Emerson says in his Essay on Compensation: “Polarity, or action and reaction, we meet in every part of Nature; in darkness and light; in the ebb and flow of waters; in male and female; in the inspiration and expiration of plants and animals; in the undulations of fluids and of sound; in the centripetal and centrifugal gravity; in electricity, galvanism, and chemical affinity. Superinduce Magnetism at one end of a needle, the opposite Magnetism takes place at the other end. If the South attracts, the North repels. An inevitable dualism besets nature, so that each thing is a half, and suggests another to make it whole: as spirit, matter; man, woman; odd, even; subjective, objective; in, out; upper, under; motion, rest; yea, nay.”
These, by whatever name we like to call them, are facts and not fancies, and facts which enter largely into all questions, whether of science, philosophy, religion, or practical policy. Every one who wishes to keep at all abreast with modern culture, ought to have some general knowledge of the ideas and principles which underlie them and which are embraced in the comprehensive word “polarity.” My object in this book has been to assist the reader, who is not a specialist, in arriving at some general understanding of the subjects treated of, and I may hope, in awakening such an interest in them as may induce him to prosecute further researches. If I succeed in this, my object will have been attained.
The reception given to my former work, on ‘Modern Science and Modern Thought,’ has induced me to write this further one. I refer not so much to the reviews of professional critics, though as a rule nothing could be more courteous and candid, but rather to the letters I have received from readers of various age, sex, and condition, saying that I had assisted them in understanding much interesting matter which had previously been a sealed book to them.
If I am good for anything, it is for a certain faculty of lucid condensation, and I have thought that I might apply this to some of the less-known branches of modern science, such as the new chemistry and physiology, as well as, in my first work, to the more familiar subjects of astronomy and geology; while at the same time I might extend it to some of the more obvious problems of religion, morals, metaphysics, and practical life, which force themselves, more and more every day, on the attention of intelligent thinkers.
As in the former work the scientific speculations were linked together by the leading idea of the universality of law, so, in this, unity is given to them by the all-pervading principle of polarity, which manifests itself everywhere as the fundamental condition of the material and spiritual universe.
For the scientific portion of the work I am indebted to the most approved authorities, such as Darwin, Huxley, Haeckel, and Professor Cooke’s volume on the New Chemistry in the International Scientific Series. For the religious and philosophical speculations I am myself responsible; for, although I have derived the greatest possible pleasure and profit from Herbert Spencer’s writings, I had arrived at my principal conclusions independently before I had read any of his works. I can only hope that I may have succeeded in presenting a good many abstruse questions in a popular form, intelligible to the average mind of ordinary readers, and calculated, if it teaches nothing else, to teach them a practical philosophy which inculcates tolerance and charity, and assists them in finding
Experiment with magnet—Principle of polarity—Applies universally—Analogies in spiritual world—Zoroastrian religion—Changes in modern environment—Require corresponding changes in religions and philosophies.
Scatter a heap of iron filings on a plate of glass; bring near it a magnet, and tap the glass gently, and you will see the filings arrange themselves in regular forms.
If one pole only of the magnet is brought near the glass the filings arrange themselves in lines radiating from that pole.
Next lay the bar-magnet on the glass so that the filings are influenced by both poles; they will arrange themselves into a series of regular curves.
In other words, the Chaos of a confused heap of inert matter has become a Cosmos of harmonious arrangement assuming definite form in obedience to law.
As the old saying has it, that ‘every road leads to Rome,’ so this simple experiment leads up to a principle which underlies all existence knowable to human faculty—that of Polarity. Why do the iron filings arrange themselves in regular curves? Because they are magnetised by the influence of the larger magnet, and each little particle of iron is converted into a little magnet with two opposite poles attracting and repelling.
What is a magnet? It is a special manifestation of the more general principle of polarity, by which energy, when it passes from the passive or neutralised into the active state, does so under the condition of developing opposite and conflicting energies: no action without reaction, no positive without a negative, and, as we see it in the simplest form in our magnets, no North Pole without a South Pole—like ever repelling like and attracting unlike. The magnet, again, may be considered as a special form of electricity, for if we send an electric current through a coil of copper wire encircling a bar of soft iron, the bar is at once converted into a magnet; so that a magnet may be considered as the summing up, at two opposite extremities or poles, of the attractive and repulsive effects of electric currents circulating round it. But this electricity is itself subject to the law of polarity, whether developed by chemical action in the form of a current or electricity in motion, or by friction in the form of statical electricity of small quantity but high tension. In all cases a positive implies a negative; in all, like repels like and attracts unlike. Conversely, as polarity produces definite structure, so definite structure everywhere implies polarity.
The same principle prevails not only throughout the inorganic or world of matter, but throughout the organic or world of life, and specially throughout its highest manifestations in human life and character, and in the highest products of its evolution, in societies, religions, and philosophies. To show this by some familiar and striking examples is the main object of this book.
But here let me interpose a word of caution. I must avoid the error which vitiates Professor Drummond’s interesting work on ‘Natural Law in the Spiritual World,’ of confounding analogy and identity. Because the principle of polarity pervades alike the natural and spiritual worlds, I am far from assuming that the laws under which it acts are identical; and that virtue and vice, pain and pleasure, ugliness and beauty, are products of the same mathematical changes of sign and inverse squares or cubes of distances, as regulate the attractions and repulsions of molecules and atoms. All I say is, that the same pervading principle may be traced wherever human thought and human knowledge extend; that it is apparently, for some reason unknown to us, the essential condition of all existence within the sphere of that thought and that knowledge; and that what lies beyond it is the great unknown, behind the impenetrable veil which it is not given to mortals to uplift. In like manner, if I call myself ‘a modern Zoroastrian,’ it is not that I wish or expect to teach a new religion or revive an old one, to see Christian churches dedicated to Ormuzd, or right reverend bishops exchanging the apron and shovel-hat for the mitre and flowing robes of the ancient Magi; but simply this. All religions I take to be ‘working hypotheses,’ by which successive ages and races of men try to satisfy the aspirations and harmonise the knowledge which in the course of evolution have come to be, for the time, their spiritual equipment. The best proof of any religion is, that it exists—i.e. that it is part of the same evolution, and that on the whole it works well, i.e. is in tolerable harmony with its environment. When that environment changes, when loftier views of morality prevail, when knowledge is increased and the domain of science everywhere extends its frontier, religions must change with it if they are to remain good working, and not become unworkable and unbelievable hypotheses.
Now of all the religious hypotheses which remain workable in the present state of human knowledge, that seems to me the best which frankly recognises the existence of this dual law, or law of polarity, as the fundamental condition of the universe, and, personifying the good principle under the name of Ormuzd, and the evil one under that of Ahriman, looks with earnest but silent and unspoken reverence on the great unknown beyond, which may, in some way incomprehensible to mortals, reconcile the two opposites, and give the final victory to the good.
So sings the poet of the nineteenth century: so, if we understand his doctrine rightly, taught the Bactrian sage, Zoroaster, some forty centuries earlier.
This, and this alone, seems to me to afford a working hypothesis which is based on fact, can be brought into harmony with the existing environment, and embraces, in a wider synthesis, all that is good in other philosophies and religions.
When I talk of our new environment, it requires one who, like the author, has lived more than the Scriptural threescore and ten years, and has, so to speak, one foot on the past and one on the present, to realise how enormous is the change which a single generation has made in the whole spiritual surroundings of a civilised man of the nineteenth century. When I was a student at Cambridge, little more than fifty years ago, Astronomy was the only branch of natural science which could be said to be definitely brought within the domain of natural law. And that only as regards the law of gravity, and the motions of the heavenly bodies, for little or nothing was known as to their constitution. Geology was just beginning the series of conquests by which time and the order and succession of life on the earth have been annexed by science as completely as space by astronomy; and theories of cataclysms, universal deluges, and special recent creations of animals and man, still held their ground, and were quoted as proofs of a universe maintained by constant supernatural interference.
And when I say that space had been annexed to science by astronomy, it was really only that half of space which extends from the standpoint of the human senses in the direction of the infinitely great. The other equally important half which extends downwards to the infinitely small was unknown, or the subject only of the vaguest conjectures.
Chemistry was, to a great extent, an empirical science, and molecules and atoms were at best guesses at truth, or rather convenient mathematical abstractions with no more actual reality than the symbols of the differential calculus. The real causes and laws of heat, light, and electricity, were as little known as those of molecular action and of chemical affinity. The great laws of the indestructibility of matter, the correlation of forces, and the conservation of energy, were unknown, or only just beginning to be foreshadowed. As regards life, protoplasm was a word unheard of; scientific biology, zoology, and botany were in their infancy; and the gradual building up of all living matter from a speck of protoplasm, through a primitive cell, was not even suspected. Above all, the works of Darwin had not been published, and evolution had not become the general law of modern thought; nor had the discovery of the antiquity of man, and of his slow development upwards from the rudest origins, shattered into fragments established beliefs as to his recent miraculous creation.
Science and miracle have been fighting out their battle during the last fifty years along the whole line, and science has been at every point victorious. Miracle, in the sense in which our fathers believed in it, has been not only repulsed, but annihilated so completely, that really little remains but to bury the dead.
The result of these discoveries has been to make a greater change in the spiritual environment of a single generation than would be made in their physical environment if the glacial period suddenly returned and buried Northern Europe under polar ice. The change is certainly greater in the last fifty years than it had been in the previous five hundred, and in many respects greater than in the previous five thousand.
It may be sufficient to glance shortly at the equally great corresponding changes which this period has witnessed in the practical conditions of life and of society. If astronomy and geology have extended the dominion of the mind over space and time, steamers, railways, and the electric telegraph have gained the mastery over them for practical purposes. Commerce and emigration have assumed international proportions, and India, Australia, and America are nearer to us, and connected with us by closer ties, than Scotland was to England in my schoolboy days. Education and a cheap press have even in a greater degree revolutionised society, and knowledge, reaching the masses, has carried with it power, so that democracy and free-thought are, whether for good or evil, everywhere in the ascendant, and old privileges and traditions are everywhere decaying.
With such a great change of environment it is evident that many of the old creeds, institutions, and other organisms, adapted to old conditions, must have become as obsolete as a schoolboy’s jacket would be as the comfortable habiliment of a grown-up man. But as a lobster which has cast its shell does not feel at ease until it has grown a new one, so thinking men of the present day are driven to devise, to a great extent each for themselves, some larger theory which may serve them as a ‘working hypothesis’ with which to go through life, and bring the ineradicable aspirations and emotions of their nature into some tolerable harmony with existing facts.
To me, as one of those thinking units, this theory, of what for want of a better name I call ‘Zoroastrianism,’ has approved itself as a good working theory, which reconciles more intellectual and moral difficulties, and affords a better guide in conduct and practical life than any other; and, in a word, enables me to reduce my own individual Chaos into some sort of an intelligible and ordered Cosmos. I feel moved, therefore, to preach through the press my little sermon upon it, for the benefit of those whom it may concern, feeling assured that the process of evolution, by which
can best be assisted by the honest and unbiassed expression of the results of individual thought and experience on the part of any one of those units whose aggregates form the complicated organisms of religions and philosophies, of societies and of humanity.
Matter consists of molecules—Nature of molecules—Laws of their action in gases—Law of Avogadro—Molecules composed of atoms—Proved by composition of water—Combinations of atoms—Elementary substances—Qualities of matter depend on atoms—Dimensions and velocities of molecules and atoms—These are ascertained facts, not theories.
If in building a house that is to stand when the rains fall and the winds blow, it is requisite to go down to the solid rock for a foundation, so much the more is it necessary in building up a theory to begin at the beginning and give it a solid groundwork. Nine-tenths of the fallacies current in the world arise from the haste with which people rush to conclusions on insufficient premises. Take, for instance, any of the political questions of the day, such as the Irish question: how many of those who express confident opinions, and get angry and excited on one side or the other, could answer any of the preliminary questions which are the indispensable conditions of any rational judgment? How many marks would they get for an examination paper which asked what was the population of Ireland; what proportion of that population was agricultural; what proportion of that agricultural population consisted of holders of small tenements; what was the scale of rents compared with that for small holdings in other countries; how much of that rent was levied on them for their own improvements; and other similar questions which lie at the root of the matter? In how many cases would it be found that the whole superstructure of their confident and passionate theories about the Irish difficulty was based on no more solid foundation than their like or dislike of a particular statesman or of a particular party?
I propose therefore to begin at the beginning, and, taking the simplest case, that of dead or inorganic matter, show how the material universe is built up by the operation of the all-pervading law of polarity. What does matter consist of? Of molecules, and molecules are made up of atoms, and these are held together or parted, and built up into the various forms of the material universe, primarily by polar forces.
Let me endeavour to make this intelligible to the intelligent but unscientific reader. Suppose the Pyramid of Cheops shown for the first time to a giant whose eye was on such a scale that he could just discern it as a separate object. He might make all sorts of ingenious conjectures as to its nature, but if microscopes had been invented in Giant-land and he looked through one, he would find that it was built up, layer by layer, on a regular plan and in determinate lines and angles, by molecules, or what seemed to him almost infinitely small masses, of squared stone. For pyramid write crystal, and we may see by the human sense, aided by human instruments and human reason, a similar structure built up in the same way by minute particles. Or again, divide and subdivide our iron filings until we reach the limit of possible mechanical division discernible by the microscope; each one remains essentially a bar of iron, as capable of being magnetised, and showing the same qualities and behaviour under chemical tests as the original bar of iron from which the filings were taken. This carries us a long way down towards the infinitely small, for mechanical division and microscopic visibility can be carried down to magnitudes which are of the order of 1/100000th of an inch.
But this is only the first step; to understand our molecules we must ascertain whether they are infinitely divisible, and whether they are continuous, expanding by being spread out thinner and thinner like gold-beater’s skin: or are they separate bodies with intervals between them, like little planets forming one solar system and revolving in space by fixed laws. Ancient science guessed at the former solution and embodied it in the maxim ‘that nature abhors a vacuum’: modern science proves the latter.
In the first place bodies combine only in fixed proportions, which is a necessary consequence if they consist of definite indivisible particles, but inconceivable if the substance of each is indefinitely divisible. Thus water is formed in one way and one only: by uniting one volume or molecule of oxygen with two of hydrogen, and any excess of one or the other is left out and remains uncombined. But if the molecules could be divided into halves, quarters, and so on indefinitely, there can be no reason why their union should take place always in this one proportion and this only.
A still more conclusive proof is furnished by the behaviour of substances which exist in the form of gases. If a jar is filled with one gas, a second and third gas can be poured into it as readily as into a vacuum, the result being that the pressure on the sides of the jar is exactly equal to the sum of the separate pressures of each separate gas. This evidently means that the first gas does not occupy the whole space, but that its particles are like a battalion of soldiers in loose skirmishing order, with such intervals between each unit that a second and third battalion can be marched in and placed on the same ground, without disturbing the formation, and with the result only of increasing the intensity of the fire.
Now gas is matter as much as solids or liquids, and in the familiar instance of water we see that it is merely a question of more or less heat whether the same matter exists as ice, water, or steam. The number and nature of the molecules is not changed, only in the one case they are close to one another and solidly linked together; in the other, further removed and free to move about one another, though still held together as a mass by their mutual attractions; and in the third, still further apart, so that their mutual attraction is lost and they dart about, each with its own proper motion, bombarding the surface which contains them, and by the resultant of their impacts producing pressure.
In this latter and simpler form of gas the following laws are found to prevail universally for all substances. Under like conditions volumes vary directly as the temperature and inversely as the pressure. That is to say, the pressure which contains them remaining the same, equal volumes of air, steam, or any other substance in the state of gas, expand into twice the volume if the temperature is doubled, three times if it is tripled, and so on; contracting in the same way if the temperature is lowered. If on the other hand the temperature remains constant, the volume is reduced to one half or one third, if the pressure is doubled or tripled. From these laws the further grand generalisation has been arrived at, that all substances existing in the form of gas contain the same number of molecules in the same volume.
This, which is known as the Law of Avogadro, from the Italian chemist by whom it was first discovered, is the fundamental law of modern chemistry, and the key to all certain and scientific knowledge of the constitution of matter and of the domain of the infinitely small, just as much as the law of gravity is to action of matter in the mass, and the resulting conditions and motions of mechanics and astronomy.
This conclusion obviously follows from it, that difference of weight in different substances arises not from one having more molecules in the same volume than another, but from the molecules themselves being heavier. If we weigh a gallon or litre of hydrogen gas, which is the lightest known substance, and then weighing an equal volume of oxygen gas find that it is sixteen times heavier, we know for certain that the molecule or ultimate particle of oxygen is sixteen times heavier than that of hydrogen.
It is evident that in this way the molecules of all simple substances which can exist in the form of pure gas can be weighed, and their weight expressed in terms of the unit which is generally adopted, that of the molecule of the lightest known substance, hydrogen. But science, not content with this achievement, wants to know not the relative weight only, but the absolute dimensions, qualities, and motions of these little bodies; and whether, although they cannot be divided further by mechanical means, and while retaining the qualities of the substances they build up, they are really ultimate and indivisible particles or themselves composites.
Chemistry and electricity give a ready answer to this latter question. Molecules are composites of still smaller bodies, and to get back to the ultimate particle we must go to atoms. All chemical changes resolve themselves into the breaking up of molecules and rearrangement of their constituent atoms. If the opposite poles of a voltaic battery are inserted in a vessel containing water, molecules of water are broken up, bubbles of gas rise at each pole, and if these are collected, the gas at the positive pole is found to be oxygen, and that at the negative pole hydrogen. Nothing has been added or taken away, for the weight of the two gases evolved exactly equals that of the water which has disappeared. But the molecules of the water have been broken up, and their constituents reappear in totally different forms, for nothing can well be more unlike water than each of the two gases of which it is composed. That it is composed of them can be verified by the reverse experiment of mixing the two gases together in the same proportion of two volumes of hydrogen to one of oxygen as was produced by the decomposition of water, passing an electric spark through the vessel containing the mixture, when with a loud explosion the gases reunite, and water is formed in precisely the same quantity as produced the volumes of gas by its decomposition. Can the ultimate particles of these gases be further subdivided; can they, like those of water, be broken up and reappear in new forms? No; there is no known process by which an atom of oxygen can be made anything but oxygen, or an atom of hydrogen anything but hydrogen.
The only thing which is compound in the composition of oxygen is that its molecules consist of two atoms linked together. This appears from the fact that while the weight of oxygen, and therefore that of its molecules, is sixteen times greater than that of an equal volume of hydrogen, and therefore of hydrogen molecules, it combines with it in the proportion not of sixteen, but of eight to one. If, therefore, the molecule were identical with the atom of oxygen, we must admit that the atom could be halved, which is contrary to its definition as the ultimate indivisible particle of the substance oxygen. But if the oxygen molecule consists of two linked atoms, O—O, and the hydrogen molecule equally of two, H—H, as can be proved by other considerations, everything is explained by assuming that the molecule of water consists of two atoms of hydrogen linked to one of oxygen, or H₂O, and that when this molecule is broken up by electricity, its constituents resolve themselves into atoms, which recombine so as to form twice as many molecules of hydrogen, H—H, as of oxygen, O,—i.e. into two volumes of hydrogen gas to one of oxygen.
Taking the single hydrogen atom as the unit of weight as being the lightest known ponderable body, and calling this weight a microcrith, or standard of the smallest of this order of excessively small weights, this is equivalent to saying that the weight of an oxygen atom is equal to 16 microcriths, and as water is composed of one such atom plus two of hydrogen, the weight of its molecule ought to be 16 + 2 = 18, which is in fact the exact ratio in which the weight of a volume of steam, or water in the form of gas, is heavier than an equal volume of hydrogen.
This key unlocks the whole secret of the chemical changes and combinations by which matter assumes all the various forms known to us in the universe.
Thus oxygen enters into a great variety of combinations forming different substances, but always in the proportion which is either 16, or some multiple of 16, such as 32, 48, 64. That is, either 1, 2, 3, or 4 atoms of oxygen unite with other atoms to form the molecules from which these other substances are made.
One atom of oxygen weighing 16 microcriths combines, as we have seen, with two atoms of hydrogen weighing 2, to form a molecule of water weighing 18 mc. In like manner one atom of oxygen, 16 mc., combines with one of carbon, which weighs 12 mc., to form a molecule of carbonic oxide weighing 28 mc.; and two of oxygen, 32 mc., with one of carbon, 12 mc., to form a molecule of carbonic dioxide weighing 44 mc.
The same applies to all elementary substances. Thus hydrogen, two atoms of which combine with one of oxygen to form water, combines one atom to one with chlorine to form the molecule of hydrochloric acid, which weighs 36·5 mc., being the united weights of one atom of chlorine, 35·5 mc., and one of hydrogen, 1 mc. These, with hundreds of similar instances, are the results not of theories as to molecules and atoms, but of actual facts, ascertained by innumerable experiments made independently by careful observers over long periods of years, many of them dating back to the labours of the alchemists of the middle ages in pursuit of gold. The atomic theory is the child and not the parent of the facts, and is indeed nothing but the summary of the vast variety of experiments which led up to it, as Newton’s law of gravity is of the facts known to us with regard to the attractions and motions of matter in the mass. But as Newton’s law enables us to predict new facts, to calculate eclipses and the return of comets beforehand, and to compile nautical almanacs; so the new chemistry, based on the atomic theory, affords the same conclusive proof of its truth by enabling us in many cases to predict phenomena which are subsequently verified by experiment, and to infer beforehand what combinations are possible, and what will be their nature.
The actual existence, therefore, of molecules and atoms is as well-ascertained a fact, as that of cwts. and lbs., or of planets and stars, of solar systems and nebulæ.
The researches of chemists have succeeded in discovering about 70 substances, of which the same may be said as of the oxygen and hydrogen into which water is decomposed, viz. that they cannot be decomposed by any known process, and must therefore be considered as ultimate and elementary. Their atoms differ widely in size and weight: that of mercury, for instance, being 200 times heavier than that of hydrogen, and the weights varying from 1 mc. for the hydrogen atom, up to 240 for that of uranium. When we call them elementary substances, we merely mean that we know no means of decomposing them. It is possible that all of them may be compounds which we cannot take to pieces of some substratum of uniform matter, and it is remarkable that the weight of nearly all of these elementary atoms is some simple multiple of that of hydrogen, pointing to their being all combinations of one common substratum of matter; but this is merely conjecture, and in the present state of our knowledge we must assume these 66 or 71 ultimate particles or atoms to be the indivisible units out of which all the complicated puzzle of the material universe is put together. They are not all equally important to us. Of the 71 elementary substances enumerated in chemical treatises, 5 are doubtful, and 30 to 35 of the remainder are either known only to chemists in minute quantities, or exist in nature in small quantities, having no very material bearing upon man’s relation to matter. The most important are oxygen, hydrogen, nitrogen, and carbon. Oxygen diluted by nitrogen gives us the air we breathe, combined with hydrogen the water we drink, and with metals and other primitive bases the solid earth on which we tread. Carbon again is the great basis of organised matter and life, to which it leads up by a variety of complex combinations with oxygen, hydrogen, and nitrogen.
The qualities and relations of elementary atoms afford a subject of great interest, but of such vast extent that those who wish to understand it must be referred to professed works on modern chemistry. For the present purpose it is sufficient to say that the following conclusions are firmly established.
All the various forms of matter are composed of combinations of primitive atoms which form molecules, the molecules being neither more nor less than very small pieces of ordinary matter.
The qualities of this matter, or, what is the same thing, of its molecules, depend partly on the qualities of the atoms, which are something quite distinct from those of the molecules, and partly on their mode of aggregation into molecules, affecting the form, size, stability, and other attributes of the molecule.
All matter, down to the smallest atom, has definite weight and is indestructible. No man by taking thought can add the millionth of a milligramme to the weight of any substance, or make it either more or less than the sum of the weights of its component factors, any more than he can add a cubit to his stature. When Shelley sang of the cloud,
he enunciated a scientific axiom of the first importance. Creation, in the sense of making something out of nothing, is a thing absolutely unknown and unknowable to us. If we say we make a ship or a steam-engine, we simply mean that we transform existing matter and existing energies into new combinations, which give results convenient for our purpose. So if we talk of making a world, our idea really is that if our powers and knowledge were indefinitely increased we might be able, given the atoms and energies with their laws of existence, to put them together so as to produce the desired results. But how the atoms and their inherent laws got there is a question as to which knowledge, or even conceivability, is impossible, for it altogether transcends human experience.
Before finally taking leave of atoms it may be well to state shortly that science, not content with having proved their existence and weighed them in terms of the lightest element, the hydrogen atom, has attempted, not without success, to solve the more difficult problem of their real dimensions, intervals, and velocities. This problem has been attacked by Clausius, Sir W. Thomson, Clerk Maxwell, and others, from various sides: from a comparison with the wave-lengths of light; with the tenuity of the thinnest films of soap-bubbles just before they burst, and when they are presumably reduced to a single layer of molecules; and from the kinetic theory of gases, involving the dimensions, paths, and velocities of elastic bodies, constantly colliding, and by their impacts producing the resulting pressure on the confining surface. All these methods involve such refined mathematical calculations that it is impossible to explain them popularly, but they all lead to nearly identical results, which involve figures so marvellous as to be almost incomprehensible. For instance, a cubic centimetre of air is calculated to contain 21 trillions of molecules—i.e. 21 times the cube of a million, or 21 followed by 18 ciphers; the average distance between each molecule equals 95 millionths of a millimetre, which is about 25 times smaller than the smallest magnitude visible under a microscope; the average velocity of each molecule is 447 metres per second; and the average number of impacts received by each molecule in a second is 4,700 millions.
Ether proved by light—Light-waves—Elasticity of ether—Its universal diffusion—Influences molecules and atoms—Is influenced by them—Successive orders of the infinitely small—Illustrated by the differential and integral calculus—Explanation of this calculus—Theory of vortex rings.
Perhaps the best way to convey some idea of this order of magnitudes to the ordinary reader is to quote Sir W. Thomson’s illustration, that if we could suppose a cubic inch of water magnified to the size of the earth—i.e. to a sphere 24,000 miles in circumference—the dimensions of its ultimate particles, magnified on the same scale, or, as he expresses it, its degree of coarse-grainedness, would be something between the size of rifle-bullets and cricket-balls.
Extraordinary as these dimensions are, they are not more so than those at the opposite extremity of the scale, where the distance of stars and nebulæ has to be measured by the number of thousand years their light, travelling at the rate of 192,000 miles per second, takes to reach us. Infinitely small, however, as those dimensions appear to our original conceptions derived from our natural senses, they are certain and ascertained facts, if not as to the precise figures, yet beyond all doubt as to the orders of magnitude. In dealing with them also we are to a great extent on familiar ground. Molecules are nothing more nor less than small pieces of ordinary matter; and atoms are also matter, for they obey the law of gravity, have definite weights, and build up molecules as surely as molecules build up ordinary matter, and as squared stones build up pyramids.
But to understand the constitution of the material universe we must go a step further, part from the familiar world of sense, and deal with an all-pervading medium, which is at the same time matter and not matter, which lies outside the laws of gravity, and yet obeys other laws intelligible and calculable by us; of which it may be said we know it and we know it not. We call it Ether.
Ether is a medium assumed as a necessary consequence from the phenomena of light, heat, and electricity—primarily from those of light. Respecting light two facts are known to us with absolute certainty.
1st. It traverses space at the rate of 192,000 miles per second.
2nd. It is propagated not by particles actually travelling at this rate, but, like sound through air, by the transmission of waves.
The first fact is known from the difference of time at which eclipses of Jupiter’s satellites are seen according as the earth is at the point of its orbit nearest to or farthest from Jupiter—i.e. from the time light takes to traverse the diameter of the earth’s orbit, which is about 180 millions of miles; and this velocity of light is confirmed by direct experiments, as by noting the difference of time between seeing the flash and hearing the sound of a gun, which gives the velocity of light compared with the known velocity of sound.
The second fact is equally certain from the phenomena of what are called interferences, when the crest of one wave just overtakes the hollow of a preceding one, so that, if the two waves are of equal magnitude, the oscillations exactly neutralise one another, and two lights produce darkness. This is shown in a thousand different ways, and for all the different colours depending on different waves into which white light is analysed when passed through a prism. It is a certain result of wave-motion, and of wave-motion only, and therefore we know without a doubt that light is propagated by waves.
But waves imply a medium through which waveforms are transmitted, for waves are nothing but the rhythmic motion of something which rises and falls, or oscillates symmetrically about a mean position of rest, slowly or quickly according to the less or greater elasticity of the medium. The waves which run along a large and slack wire are large and slow, those along a small and tightly stretched wire are small and quick; and from the data we possess as to light, its velocity of transmission, its refraction when its waves pass from one medium into another of different density, and from the distance between the waves as shown by interference, it is easy to calculate the lengths and vibratory periods of the waves, and the elasticity of the medium through which such waves are transmitted.
The figures at which we arrive are truly extraordinary. The dimensions and rates of oscillations of the waves which produce the different colours of visible light have been measured and calculated with the greatest accuracy, and they are as follows:
Dimensions of Light-Waves.
| Colours | No. of waves in one inch |
No. of oscillations in one second |
|---|---|---|
| Red | 39,000 | 477,000,000,000,000 |
| Orange | 42,000 | 506,000,000,000,000 |
| Yellow | 44,000 | 535,000,000,000,000 |
| Green | 47,000 | 577,000,000,000,000 |
| Blue | 51,000 | 622,000,000,000,000 |
| Indigo | 54,000 | 658,000,000,000,000 |
| Violet | 57,000 | 699,000,000,000,000 |
The elasticity of this wonderful medium is even more extraordinary.
The rapidity with which wave-motion is transmitted depends, other things being equal, on the elasticity of the medium, which is proportional to the square of the velocity with which a wave travels through it. As the velocity of the sound-wave in air is about 1,100 feet in a second, and that of the light-wave about 192,000 miles in the same time, it follows that the velocity of the latter is about a million times greater than that of the former, and if the density of ether were the same as that of air, its elasticity must be about a million million times greater. But the elasticity is the same thing as the power of resisting compression, which in the case of air we know to be about 15 pounds to the square inch; so that the ether, if equally dense, would balance a pressure of 15 million million pounds to the square inch—that is, it would require a pressure of about 750 millions of tons to the square inch to condense ether to the density of air. On the other hand, its density, if any, must be so infinitesimally small that the earth moving through it in its orbit with a velocity of 1,100 miles a minute suffers no perceptible retardation.
Consider what this means. Air blowing at the rate