FORCE AND ENERGY FRIXTKn BY SrOTTUWOODB AND CO. KKW*TI1KET SgUARI UiNOOK FOECE AND ENEEGY A THEORY OF DYNAMICS BY GKANT ALLEN LONDON LONGMANS, GREEN, AND CO AND NEW YORK: 15 EAST 16'» STREET 1888 .m ri^hlt rtstrifl ^ib'bG^ rOSTEIilS INVENTIONIS FOIiTASSE PIGNVS APOLOGY. It is with the profoundest dilTulenre that I set forth this ]K)()k. ;My best excuse for its pubhcatioii now may j)ro])ably ])e foiuul in the circumstances under which I have been induced at last to rush into print witli it. The work has hiin by me for nearly double the time prescribed in the familiar Iloratian maxim. Some fourteen years a<ro, when I was head of a Government college in Jamaica, the perusal of certain dynamical treatises of Clerk ^Nfax well's, Tait's, Balfour Stewart's, and Ilelmholtz's, surrgested to my mind sundry pro- found difficulties in the current conception of the nature of Energy. Puzzling out these difficulties conscientiously with myself, as best I might, I began at length to see, or think I saw, a way out of them by means of a new theory of my own. Tliis theory, which, right or wrong, gradually grew clear to my mental vision, I embodied in a little twenty-page pamphlet bearing the same title as the present work, and printed privately at Oxford in 187') for distribu- viii APOLOGY tioii to a few j)hy.sical specialists. Not many of tlie specialists, I fear, looked at my lucubrations : those who did returned me one or other of two ai)parently contradictory criticisms. Some of them said my theory was only just what was already known and universally acknowledged. Others of them said it was diame- trically oi)posed to what was already known, and be- trayed an elementary ignorance of the entire matter. To the ignorance thus imputed I will candidly plead guilty, and will proceed to explain wliy, in spite of it, I have ventured after so long a lapse of time to ob- trude my speculations upon a learned audience. In 1877 I returned once more dcfmitcly to the fiu])ject, in which my interest had never in any way declined, and, mainly for the sake of clarifying and systematising my own conceptions, worked out my nebulous ideas in full in the present treatise. But finding from the reception accorded to my tentative little pamphlet that physicists were not likely (then, if ever) to admit my contention, and convinced that they knew a great deal more about the matter at stake than I did, I put the comi)leted manuscript severely away in my desk, where it has remained ever since in peace and quiet among a great many more rejected juvenile performances. There it might have remained to all time but for an accidental coincidence which ha})peued a few years back. APOLOGY is Tlie coincidence came about in this ^vay. My friend Edward Clodd submitted to me in the summer of 1885 the first rough sketch of his recent work ' The Story of Creation.' In discussing with him the out- line of that book, and especially certain points con- nected with his conception of Force as there embodied, I found he had lighted upon some of the self-same fundamental difliculties which had originally led me to the views set forth in this little volume. In the course of our conversations on these moot questions I ventured very gently to hint at my own heresies, while disclaiming any desire to poison his mind with them : indeed, so anxious was I not to mislead my friend in this matter that itwMswith great reluctance I at last consented to lend him the old and crumpled manuscript of my early essay. On reading it over, he told me it had entirely dissipated his difliculties, and had set the whole question for him in a new light. Furthermore, to my unfeigned dismay and distress, he announced that he intended to ein])ody the theory in outline in the dynamical portion of his forthcoming work. Much alarmed, I endeavoured to dissuade him from so rash a course, seeing that like myself he was no physicist, and that the doctrine was new, strange, and heterodox : but so great was his confidence in the truth of the theory that my protests fell flat upon un- willing ears. lie incorporated the heretical concept ion X APOLOGY ill 'Tlie Story of Croat ion,' and, as I feared be* forcliaiid, suffered not a little for his generous rashness at the liands of the critics. A monomaniac who has found one other j)erson to share his monomania miglit perhaps liave been ex- cused for jumping to the conclusion that the rest of the world would probably give him a fair hearing. Hut I w^as far too afraid of mathematical opinion to venture even so upon publishing my ])r()bably crude and in- correct ideas. I still refrained from any attempt to print my book, till I saw that the attacks upon Mr. Clodd's position almost made it a point of honour for me to lay the facts in their integrity before tlie judg- ment of the scientific world. It was not right my fri(Mid should suffer for my own transgression. Cri- ticism was levelled at the necessarily brief and bald abstract he had given of what I may venture to call our joint opinion : I thought it only projjcr, in justice to him, that the theory as a whole should be put in evidence for the jury of experts to examine and decide upon. I don't for a numient suppose they will take the trouble to look into it at all : but at anv rate 1 have now discharmul mv dutv — I'lhevavi. (tnunam mcam. — the evidence is here, and who will mav C(Mi- sider it. Nobody could be more sensible than T nm how little likely it is lh;it n mere amateur should hit upon APOLOGY xi a true penoralisation in science missed by tlic recog- nised leaders of j)liysical thou<rlit. For tliis reason, I M'ould never have publislied my treatise at all (pro- foundly as I myself believe in it) had it not been for ^fr. Clodd's intervention, with its remoter consequences. As it is, however, I may plead in extenuation this further excuse. ThethouLdits one entertains, says the greatest of living English thinkers, are as children born to one which one may not willinjrlv let die. There can be no harm, therefore, in putting them forth to the world, in a tentative wav, with all due niodestv, provided always it is clearly understood that they are ])ut forth as suggestions alone, for wiser heads to ac- cept or reject at leisure. If ])erchance it shoidd lia])pen that one has iiuleed hit almost by accident upon a true and luminous ])rinci])le, one owes it to humanity to set that })rinci})le forward at once, in s|)ite of the natural fear of criticism and ridicule. The would-be discoverer is ])robably wrong: but when by any stroke of luck he chances to be right, it is for the good of the world that he should })ul)lish his discovery. In this light, therefore, I venture to beg the professional critic to examine my work. It pretends to be no more than a suggestion, an (ijxnuin^ anattem[)tat a theory: I ask for it nothing belter than honest consideration : for if tliis counsel or (his work be of men, it will come to nouglit : and 1 have xii ArOLOGV no desire to aid in the promulgation or difl'usion of error. For the same reason, I will not apologise for the seemingly dogmatic mould in which the treatise itself is cast. IJeing nothing more than an endeavour to express in words the fundamental dynamical con- stitution of the universe, as it envisages itself to a particular inquirer, I have thought it best to use the purely impersonal form, and to state each proposition as simple fact, leaving the reader to bear in mind for himself throughout, that the whole is suggestion or conception merely. At the same time, I sincerely trust scientific readers (if I am fortunate enough to attract any) will approach the theory with an unbiassed mind, and instead of rejecting it offhand at the first glance, be- cause its conceptions do not agree with those to which they are already accustomed, will do me the justice to read it through before deciding, and to place themselves as far as possible in sympathy with my point of view. I grant at once that the idea of Energy they will here find embodied is not at all the idea liithcrto framed by men of science. It is a new idea ; and that is exactly why I have written this little treatise. If I am right (as I jnobably am not) our concepts of Energy will have to undergo a consider- able revision. That being just the question at issue APOLOGY xiii lioiv, I hope readers will duly consider it, instead of taking the current view dogmatically for granted, and crushing nie by pointing out that mine does not coincide with it. A petitio principii is no re- futation. The long time I have kept this treatise by me unpubhshed ouglit to supply ^ufTicient proof of the extreme timidity with which I myself regard it. That timidity may perhaps be allowed to protect me from harsh, unkindly, and contemptuous criticism. If I am wrong, of course, I shall expect to be frankly told so: I shall accept demonstration of my mistakes and misconceptions with a good grace. Naturally, I shall continue still to think myself right : it is not in human nature to do otherwise : the theory has too long interwoven itself into all my conceptions of the physical world to be easily rooted out of the fibres of my brain now after so many years. Ihit having once consented to trot out my little heresy unwillingly before the eyes of the world, I shall drop it in public henceforth and for ever. I will make no angry replies to authoritative expositions of my blunders or errors : I will abstain from imitating the common paradox-monger, who, hardened in his obliquity, sees only unfair attacks and unworthy motives in demon- strative criticism. ' I'm not a-arguin* with you ; I'm only a-tellin' of you,' said a pothouse politician to an xiv APOLOGY obtuse friend. I don't expect to be argued with : I shall be satisfied to be told. Under these circumstances, and in consideration of previous good conduct, I earnestly trust the court of scientific opinion will let me off with a caution or a nominal fine. My promise never to recur to the subject again may surely in such a case be counted to me for righteousness. At a certain college exami- nation, where proof of age was required from all intending candidates, a certain colonial-born under- graduate brought with hhu perforce his only docu- mentary evidence, a certificate of baptism. The examiner, a well-known heterodox don, glanced at the ecclesiastical certificate curiously. ' How's this ? ' he asked in a hurried voice. ' How's this ? You've been baptised, sir?' The luckless undergraduate timidly stammered out that it was a mistake due to the imperfect registration system of his native land. ' H'm,' snorted the examiner : ' oh, very well, then : as you were baptised by mistake, it won't be allowed to tell against you.' May I venture to express a humble hope that on this occasion too a heresy extorted from me under such peculiar circumstances will not be allowed to tell against my character ? COJ^TENTS. PART L ABSTRACT OR ANALYTIC. • IIAITKR I. I'OWF.U . . . . . II. KOUCE .... III. EXEUGY ..... IV. THE SPECIES OF FOUCE V. THE SI'ECIES OF ENEUGY VI. THE MODES OF ENEIIQY VII. THE KINDS OF KINESIS . VIII. THE PERSISTENCE OF FOKCE IX. THE CONSEKVATION OF ENEHGY X. THE INDESTUUCTllULITY OF POWEK XI. THE MUTUAL INTEKFEUENCE OP FOUCES XII. THE SUPPHESSION OP ENERGIES XIII. LIHERATING ENERGIES . XIV. MISCELLANEOUS ILLUSTRATIONS XV. THE DISSIPATION OF ENERGY XVI. THE NATURE OF ENERGY XVII. THE NATURE OF MOTION TAOS 3 5 7 10 19 25 31 39 41 49 50 55 58 (J4 71 75 78 XVI COXTEA'TS PART II.-CONCRETE OR SYNTHETIC. CHAl'TKB I. DYNAMICAL FORMULA OF THE UNIVEItRK II, THE BIDEUEAL SYSTEM III. THE SOLAR SYSTEM . . . • IV. THE EARTH . . • • • V. ORGANIC LIFE . . . . • VI. THE VEGETAL ORGANISM VII. THE ANIMAL ORGANISM .... VIII. GENERAL VIEW OF MUNDANE ENERGIES »5 «9 99 108 183 IS6 147 163 Part I. ABSTRACT OR AXALYTIC B CUAPTER I. row Ell. A POWER is that wliicli initiates or terminates, ac- celerates or retards, motion in one or more particles of ponderable matter or of the ethereal medium. Power, as here understood, is thus tlie widest of all possible dynamical conceptions. It cannot be defined by genus and difTerentia, because it is itself the siimmum ijeuus of dynamical science. Accord- ingly, it will be observed that no attempt is made above to assign it to any higher class, such as thingsy entities, or concepts. Nothing would be gained, for example, by saying that a power is the tendency to initiate or terminate motion : it is best described by the indefinite statement given at the head of this chapter. It is simply that which produces or destroys^ increases or lessens, motion in any particle or particles of any substance whatsoever cognisable ])y man. Powers are of two sorts, Forces and Energies, the difFerences between which will be fully set forth in u -2 4 ABSTRACT OR ANALYTIC siil)soquent chapters. Meanwhile, as a lielp lo the provisional comprehension of the nature of Power, which can scarcely be <rraspe(I at first in the abstract terms of our formal defmition, it may be mentioned that amongst the varieties of Power are such Forces as Gravitation, Cohesion, and Chemical AfTmity, besides such Energies as Heat, Electricity, and Light. These expressions are here employed in their popidar sense, merely as guides to the sort of concept pro- visionally set forward for the, term Power, until the subsequent investigation has rendered possible a more rational and comprehensive notion in the mind of the reader. CIIAITEK II. FORCE. A FORCE is a Power wliich initiates or accelerates aggregative motion, while it resists or retards separa- tive motion, in two or more particles of ponderable matter (and possibly also of the ethereal medium). All particles possess the Power of attracting one another — in other words, of setting up mutually aggregative motion — unless prevented by some other Power of an opposite nature. Thus a body suspended freely in the air is attracted towards the earth by the Force (or aggregative Power) known as Gravitation. A piece of sugar, held close over a cup of tea, attracts into itself the water of the tea-cup, by the Force (or aggregative Power) known as Capillarity. A spoon left in tea grounds or a foot planted on the moist sand similarly attracts the neighbouring drops. A piece of iron or coal exposed to free oxygen (each at a certain fixed temperature) attracts the particles of oxygen by the Force known as Chemical Affinity. In every case there must be an absence of counteracting 6 ABSTRACT OR ANALYTIC Energies (or separative Powers) sufficient to prevent the union of tlie particles, as Avill be sliown hereafter : but for the present it will be enough to notice that every particle attracts every other particle in some one of various ways unless prevented by other Powers.^ Not only, however, do all particles thus attract one another, but they also resist all attempts to sejiarate them from one another. A weight sus- pended in the air falls to the ground : but it also resists any attempt to remove it from the ground, which can only be done by the employment of a proportionate Energy (or separative Power). The water which the sugar has absorbed can only be drawn from it by the Energy of suction. The oxygen with which the iron has united can oiily be driven off by the Energy of heat : Vv'hile the carbonic anhydride and water which resulted from the burning of the coal yield only as a rule to the separative Energy of light or electricity. In every case the Force which brought two or more particles together in the first instance keeps them united ever after, and must be neutralised by an equal Power of an opposite description before they can be disjoined. * Tlie term 'to attract' must be strictly accepted in the sense of actually setting np aggregative motion, not merely in that of a tendency to such motion. The tendency always subsists, in spite of eoimteract- ing causes, and is immediately actualised upon their removal. CUAPTEll 111. ENERGY. Ax Energy is a power wliich resists or retards ajjiirejiative motion, while it initiates or accelerates separative motion, in two or more particles of ponder- able matter or of the ethereal medium. All particles, or aggregates of particles, not ac- tually in contact with one another in stable equilibrium at the absolute zero of temperature, are kept apart by an Energy or separative Power of some sort, which prevents them from aggregating as they would other- wise do under the influence of the Forces inherent in them. Thus the moon is prevented from falling upon the earth, and the earth from falling into the sun, by the Energy of their respective orbital motions. A ball shot from a cannon into the air is prevented from falling by the Energy of its upward flight. A red-hot poker has its particles kept apart by the Energy of heat. In every case, so soon as the Energy is dissipated (as hereafter explained) the ball yields to 8 ABSTRACT OR ANALYTIC the aggregative Power of Gravitation, and the poker contracts to its ordinary dimensions ; while there is no reason to doubt that under similar circumstances the moon and the earth will aggregate with the sun. The particles of water are kept in the liquid state by the Energy known as latent heat,^ and so are those of steam : wlien the * latent heat ' u dissipated, the steam condenses and the water freezes. There are many apparent exceptions ; but they will be con- sidered at later stages of the argument. For the present, the reader must be content to understand the word Energy (when used in this treatise) only in the sense here given to it of a Power which resists or retards aggregation. Energies also initiate separative motions, Tlius, a cannon ball is raised by Energy to a distance from the main mass of the earth which usually holds it bcund by Gravitation on its surface. A poker placed in the fire has its particles separated from one another by the Energy of Heat. Wlien ice melts or water is converted into steam, tlie same Energy similarly severs their particles from one another and places them in positions of relati\^e freedom. In the electrolysis of water the Energy of the galvanic curr'^nt tears asunder the atoms of hydrogen and oxygen from their close ' I continue to employ for the present this well-known but very incorrect expression. ENERGY union in tlie compound molecule. In short, wherever we see nicasses or particles in the act of separating from one another, we know that the separation is due to some Energy. JO ARSTRACl OR ANALYTIC CHAPTER IV. THE SPECIES OF FORCE. Forces may be most conveniently divided according to tlie nature of the particles or bodies in wliicli tlicy initiate and accelerate ajjfjrefrative motion or resist and CO o retard separative motion. Of these, there are four principal kinds known to us or conjectured by us. The first kind is the Mass or visible aggregation of particles, which admits of mechanical separation into minor masses. The second kind is the Molecule, or ultimate mechanical unit, which does not admit of subdivision, except by resolution into its chemical components. The third kind is the Atom, or ultimate chemical unit, which does not admit of subdivision by any known means, though it may perhaps be resoluble hereafter into some simpler and more primitive units. The fourth is the Electrical Unit,^ whose nature is very inadequately known to us, but which must be considered for our present purpose as in some way ' Tliis conception of electrical units is provisional and purely sym- bolical ; but its use will bo apparent in later chapters. THE SPECIES OF FORCE H the analogue of tlie others, though we have no sufii- cient warrant for giving it any material properties. The Force which aggregates Masses and resists the separation of Masses is known as Gravitation. When any two Masses are left free to act upon one another without the counteracting influence of an Energy, they aggregate in obedience to this Power. When the cannon ball falls upon the earth, it is Gravitation which draws them together. When an aerolite comes within the circle of the earth's attraction, it is Gravi- tation which makes them leap towards one another. If the moon were to lose its orbital Energy, Gravita- tion would pull it to the earth ; and if our planet in her turn were suddenly checked in her course, Gravi- tation would cause her to plunge into the sun, while the sun in return would make a slight bound to meet her. Again, when any two Masses are in a state of aggregation, the Force of Gravitation resists any attempt to sever them. If the cannon ball lies upon the ground, it cannot be raised without an expenditure of Energy, and the amount of the Energy required to hft it to a given height (or distance from the surftice of the earth) is the measure of the resistance offered by Gravitation. Similarly, when the Masses are not in actual contact owing to the existence of an Energy which keeps them apart, as in the case of the earth and her satellite, or the sun and the planets, Gravi- 12 ABSTRACT OR ANALYTIC tation resists any attempt to sever tliem beyond their actual distances. It would be impossible to remove the moon a hundred miles from the earth, or the earth a hundred miles from the sun, except by the employment of an adequate Energy ; and, as in the simpler case, the amount of Energy required would be the measure of resistance offered by Gravitation. The Force wliicli afrgfrefrates Molecules and resists CO o the separation of Molecules is known as Cohesion. When any two Molecules are left free to act upon one another without the counteracting influence of an Energy, they aggregate in obedience to this Power. But the cases are much more difficult to illustrate than those of gravitation, because while masses attract one another powerfully at very conspicuous distances, Molecules (practically speaking) only attract one another at infinitesimal distances. The difference, however, which is purely relative, may thus be illus- trated and explained. An aerolite is not drawn on to the earth unless it approaches the earth very closely, because otherwise the earth's attraction, though caus- ing a deviation in its course, does not suffice to over- come the aerolite's energy and the combined attrac- tions of surroundincf bodies. But if it be near enough to be more powerful than all of them put together,^ ' I tako for granted on the reader's part a knowledge of the law of inverse sciuarcs. THE SPECIES OF FORCE IS the at-'rollte either circles round the earth as a satel- lite or even falls at once upon its surface. Similarly uith Cohesion. If two pieces of uneven iron be laid upon one another, the molecules do not approach near enough to exert any conspicuous mutual in- fluence : but if the two pieces be planed to an absolute smoothness, so that the several molecules can come within the sphereof their mutual attraction, they will cohere perfectly, and it wiU be impossible to tear them asunder. Again, in other cases. Cohesion can only be effected by such a molecular motion (or heat) as will cause the Molecules to approach one another closer than they can be induced to do by mechanical means : just as an aerolite which would not under ordinary circumstances come (practically speaking) within the sphere of the earth's attraction, might do so if it were given an os- cillating motion from side to side, so as to cross or closely approach some portion of the earth's orbit. Thus, two pieces of iron, if heated, will cohere with one another. Furthermore, the molecular motion inherent in the liquid form is often sufficient for this purpose : thus, two masses of dough, which will not cohere in the dry condition, can be made to do so by the addition of moisture. In the practice of gumming and glueing, ?re make use of this device in everyday life. A further account of these phenomena will be 14 ABSTRACT OR AXALYTIC given in the chapter on Liberating Energies. The second property of Cohesion, that of rcsivSting the separation of Molecules actually aggregated, is much more familiar to us. If two Molecules or bodies of Molecules are in an aggregated condition — that is, are not rendered plastic or liquid or gaseous by some form of Energy — we cannot separate them without a considerable expenditure of Energy. The Energy may be in the form of a mechanical action, as when we tear or break a cohering substance ; or of heat, as when we melt lead; or of the contained motion of liquids, as when we dissolve a lump of sugar. But in any case Energy must be expended to counter- act the aggregative Force of Cohesion in solid bodies. A qualification must be added to prevent miscon- ception. The cohering Molecules need not be sup- posed to be in actual physical contact with one another. It is sufficient that they should be within the sphere of one another's attraction ; just as the moon is kept in its place by the earth, and the planets by the sun, in spite of the intervening space. Theoretically, of course, every body in the universe attracts every other ; but as the attraction decreases as the squares of the distance, at practically infinite distances it becomes practically infinitesimal and can be overcome by an infinitesimal Energy. This is the case ordinarily with Cohesion : at very slight THE SPECIES OF FORCE 15 (listanoes its Force is so diminished that only an im- perceptible amount of Energy is required to counter- act it. But there is no reason to doubt that when the two rough pieces of iron are laid upon one an- other, the supporting points, so to speak, come within the sphere of mutual attraction, though their number and area are so sniall that we cannot perceive the re- sistance resulting from their Cohesion when we sepa- rate the pieces. In short, Cohesion always tends to act between all Molecules, but its effects may be dis- guised either by distance or by counteracting Energies. Other cases will be treated in the chapter on Mutual Interference of Forces. Adhesion and Capillarity are only forms of Cohesion. The Force which aggregates Atoms and resists the separation of Atoms is known as Chemical Affinity. As here employed it will be understood to mean not merely the Force which unites the Atoms of two or more elements into a compound molecule, but also the identical Force which unites two or more Atoms of the same element into a mole- cule such as that of ozone. When any two or more Atoms (or equivalents in combining propor- tions) are left free to act upon one another without the counteracting influence of an Energy, they aggre- gate in obedience to this Power. As in the case of cohesion, however, the Atoms must be brought into •l6 ABSTRACT OR ANALYTIC close contact with one another. When phosphorus is exposed to oxygen the aggregation is immediate. But in other jases a certain amount of molecular or Atomic motion is needed in order to bring the Atoms within the sphere of their mutual attractions. Thus heat is necessary to make carbon combine with oxygen, as in the ordinary phenomenon of combus- tion : while the more subtle motion of light suffices to effect a union between hydrogen and chlorine. But we may broadly assert that whenever free Atoms find themselves in the presence of a free Atom for which they have affniities (the proper proportions being of course supposed), and are brought within the sphere of their mutual attraction, the two Atoms or sets of Atoms aggregate under the influence of Chemical Attraction. Here, again, a qualification is needed. The above rule holds only ioT free Atoms. Just as a ball suspended by a rope from the ceiling does not fall to the ground, because the Force of cohesion outbalances the Force of gravitation, so, when two or more Atoms, united in stable combina- tion, are brought into contact with other Atoms for which they have affinities less strong than those of their existing combination, they will not yield up their stronger to their weaker affinity. (See the subsequent chapter on Mutual Interference of Forces.) And again, just as the ball will break the rope, if gravita- THE SPECIES OF FORCE I7 tion outbalances coliesion ; so, if the new afTinities are stronger than the okl ones, the Atoms will yield up tlieir previous combination and enter into that to which they are most powerfully attracted. The second mode in which Chemical Affinity acts is in re- sisting the attempt to separate the component Atoms of a compound body. Setting aside for the present certain very abnormal cases in which ' unstable ' bodies spontaneously decompose — cases which can only be explained at a very late stage of our exposi- tion — all ordinary ' stable ' compounds require an Energy to separate their Atoms. Thus heat is needed to divide the Atoms of oxA'gen from those of iron in ferric oxide : while electricity is necessary to sever the Atoms of hydrogen from those of oxygen in water. This statement must be understood as apply- ing only to the separation of free elements, not the formation of new compounds. Mere juxtaposition is sufficient to make certain compound bodies yield up their weaker affinities in the presence of stronger ones : but (with the special exception noted above, chiefly referring to organic compounds) an Energy is required to separate any compound into its compo- nent Atoms in a free state, without the aid of stronger antagonistic affinities. The Force which aggregates Electrical Units and resists the separation of Electrical Units is known as c |8 AliSTRACT OR AXAI.VTIC Elkctrkal Affinity. Tliis Force is little understood, and ran only be treated in a very syn\l)oliral manner. What few points can be formulated are briefly these. When Posit iye and Negative Electricities are left free to act within the sphere of their mutual attractions, they are aggregated by this Force, as in the discharge of a Leyden jar. In saying this, no imphcation of materiality is meant to be conveyed. In our present ignorance on the subject, Electrical Affinity must be placed in the same category as other Forces ; though further researches will doubtless enable ns to give a better account of its real nature. Similarly, an Energy is necessary to separate the Positive and Negative Electricities which subsist in combination in every material body. In the case of a glass rod or an electrical machine this Energy is that of mechani- cal motion : in certain other cases it is of thermal or chemical origin. These points will receive further consideration in the chapter on Electrical Phenomena. A table will put in a clearer light the classification here adopted. Forces or Aggregative Towers. Molar Molecular Atomic Electric Gravitation Cohesion Chemical Affinity Electrical Affinity 19 CHAPTER V. TIIK SPECIKS OF HNKRGY. E.VKRfiiHS may be most conveniently divided on the same principle as Forces, according to the nature of the particles of bodies in which they initiate or accelerate separative motion, and resist or retard arrrrreirative motion. But owiiif? to the existence of two modes of Energy, the Potential and the Kinetic, whose peculiarities will form the subject of our next chapter, it wnll not be possible to assign a single defmite name to each species, as was the case with the various Forces. It must suffice for the present to quote a few well-known instances of each. The energies which separate Masses and resist the aggregation of Masses may be summed up under the title of Molar Energies.^ Of Molar Energies em- ployed in actual separation, a familiar instance is ' We shall see hereafter that these species are in reality just as simple as those of Forces ; but for the reader's convenience they are exhibited here under familiar aspects, which give them an appearance of plurality and indefiniteness. c2 20 A US TK ACT OR AXALVT/C {^iveii in our own persons, when we lift Ji weif^ht fioni the f^roiind or carry ourselves to the fop of a hill, thereby oountera(.'tin<( the Molar Force of j^n'avitalioii by raising a body to a greater distance than before from the centre of tlie earth's attraction. Another instance is seen in a cannon ball fired vertically, or a stone lifted by a crane. On a larger scale, any fresh Energy employed in removing the moon further from the earth or a planet from the sun would be a Molar Energy. Any Mass thus separated from another attracting; Mass is said in the current languajje of physics to possess Visible Energy of Position, a term which we shall examine and endeavour to amend hereafter. Of Molar Energies employed in resist- ance to aggregation the most familiar instance is that of orbital movement. The moon is prevented by this Energy from aggregating with the earth, and the planets with the sun, as they would otlierwise do undtjr the influence of Molar Force or gravitation. On a smaller scale, the Energy of a bird in flying or a cannon ball fired horizontally is largely employed in counteracting gravitation. It is seldom, however, that we see Energy thus emjjloyed, except in the case of the heavenly bodies, because the Molar Force exerted by the earth in its immediate vicinity is so strong as to overcome ordinary Energies after a very short period of dissipation. Masses of the sort here THE SrECIES OE ESEKGY tt (Icscrihecl are said in tlit; current plu'aseology to j)ossess Energy of Visible Motion, which expression, like the ibrnier one, will receive attention at a later point. The Energies which separate Molecules and resist the aggregation of Molecules may be sununed up under the title of Molkculab Enkrgiks. Of Mole- cular Energies employed in separation we have a conunon instance in heat, which draws apart the Molecules of a red-hot poker or a mass of lioiling water, in opposition to the Molecular Force of Cohe- sion. The contained Energy of water acts in the sauie maimer on a lump of sugar or a mass of dry dough. Of Molecular Energies employed in resistance to aggregation, heat under its converse aspect affords us an exauiple. The Molecules of all Ijodies are prevented from aggregating into their most com- ])ressed form by the presence of heat. Thus the red- hot poker only contracts so fast as it loses its Energy by radiation. The contained Energy (or ' latent heat ') of water similarly prevents its aggregation into ice. Large masses of water before freezing part with their Energy in the visible form of heated uiist. The Energies wdiich separate Atoms and resist the aggregation of Atoms may be summed up under the title of Chemical Enkrgirs. A caution as to the sense in wliicli this term must be here accepted is 32 ABSTRACT OR A XA LYTIC appended below. Of Chemical Energies employed in separation we have an instance in the electrolysis of water. The Energy disengaged by the union of elements in the battery is used up in producing chemical separation between the atoms of the electro- lyte. Light produces a similar effect upon carbonic anhydride and water in the leaves of plants. Any Energy which separates a compound body into simpler or elementary bodies may be regarded as a Chemical Energy in the sense here intended. Of Chemical Energies employed in resistance to aggregation, no um uivocal instance can be cited at our present stage, though this apparent anomaly will be cleared up as we proceed. For the time the reader must be content to accept as an instance the fact that many Atoms will not combine with one another at a certain high temperature : the same temperature, in fact, at which they are driven off from their combination when actual. It will be noticed that, for the sake of uniformity, a somewhat new sense has here been given to the term ' Chemical Energy.' As ordinarily used at present, that term refers to the strength of the tendency which a body shows to unite with other bodies. It will be seen in the sequel that this is really a property depending upon separation and chemical nature : just as a body in proportion to its height and mass shows a tendencv to a<>irre<rate with THE SPECIES OF ENERGY 23 the earth : but, nieaiiwliile, it is necessary to hnpose a new sense upon the term, in keeping with the analogous term ' Chemical Affinity,' which we have applied to the i'orce that aggregates Atoms, The Energies which separate Electrical Units and resist the aggregation of Electrical Units may be summed up under the title of Elfx'TRIcal Energies. As in the case of Electrical Forces, our treatment of this department must be considered purely temporary and symbolical. Of Electrical Energies employed in separation we have an instance in the electrical machine, where friction produces a disunion of the Positive and Negative Units. Similarly in the torpedo and gymnotus. Of Electrical Energies employed in resisting aggregation there is again no ujiequivoeal instance. The illustration of this deficiencv must be left to later chapters. Throughout, both in the case of Forces and Energies, it will be noticed that the same Power which initiates and accelerates one kind of motion equally resists and retards the other kind of motion. Thus, Gravitation both initiates movements of masses to- wards centres of attraction, and resists movements of masses away from centres of attraction. Cohesion both draws molecules together, and resists the se})aniti()n of molecules : while heat dravvs molecules apart and resists the a!2fi»' re nation of molecules. So thai these ^4 ABSTRACT OK ANALYTIC two Powers, the aggregative and the separative, are incessantly opposing and antagonising one another in all bodies, great or small. The amount of aggregation reached by any system of bodies at any point of time depends upon the relative proportions of its Forces and its Energies at that moment. A table is scarcely needed for the contents of this chapter; yet for the sake of symmetry one is here appended. Energies or Separative Powers. Molar Molecular Atomic Electric Molar Energy Molecular Energy Chemical Energy Electrical Energy 3v CHAPTEE VI. TI1I<: MODES OF ENERGY. Energy has two Modes, ordinarily known as the Po- tential and the Kinetic : bnt the terms Statical and Dynamical are mncli preferable. Nevertheless, in order not to disturb unnecessarily the received ter- minology, the former expressions will be generally preserved in this treatise. The two Modes of Energy are interchangeable with one another : the Potential can pass into the Kinetic, and the Kinetic into the Potential. Each species of Energy, Molar, Molecular, Atomic, and Electrical, is represented in both modes. Potential Energy (a very bad name) is equivalent to actual or statical separation. Any mass, molecule, atom, or electrical unit, ii state of separation from other masses, molecules, atoms, or electrical units, possesses Potential Energy. The subject may con- venientlv be considered under the four heads hence arising. 26 ABSTRACT OR AXALVTIC Molar Potential Energy is equivalent to the statical separation of Masses. The moon pos- sesses this Energy relatively to the earth, and the planets to the sun,^ The cannon ball, shot vertically, has Molar Potential Energy at the instantaneous neutral point when it has reached its greatest height and has not yet begun to fall. A stone on a moun- tain top or a head of water on its side has also the same Energy. In short. Molar Potential Energy is possessed by all discrete Masses in virtue of their separation. It is commonly known as Visible Energy of Position. Molecular Potential Energy is equivalent to the statical separation of Molecules. Two planed surfaces of iron possess this Energy, until by apposition they are made to unite. The molecules of water, dispersed as steam, similarly possess it, in the form commonly known as ' latent heat.' When steam condenses or water freezes, the Energy is yielded up in the Kinetic form. Atomic Potential Energy is equivalent to the statical separation of Atoms. It is possessed by every free Atom of an element, and by every com- pound Atom whose affinities are not fully saturated. ' It may excite surprise to see these relations described as statical. The term is only employed in a relative sense, as opposed to the dynamical energy of a falling body. THE MODES OF ENERGY 27 Thus an Atom of carbon has Potential Energy in relation to two separate Atoms of oxygen, with which it may unite to form carbonic anhydride. Similarly, chlorine has Potential Energy relatively to sodium, with which it may unite to form common salt. Such cases, however, must be carefully dis- tinguished from those of preferential attraction where a body leaves its union with one element to combine with another for which it has stronger affinities : as when the CI of IICl leaves the 11 to unite with Na in XaCl. This last instance is really analogous to that of the cannon ball which breaks the rope that ties it because the Force of Gravitation has outbalanced that of Cohesion. Electrical Potential Energy is equivalent to the statical separation of Electrical Units. In a Leyden jar, the opposite electricities of the inner and outer coats exhibit this relation. In a thunder cloud and the earth beneath it we have a substantially similar division of the Positive and Negative Units. The state- ment of these facts must be accepted with the usual caution as to the purely symbolical nature of our electrical conceptions. From the potential we pass on to the Kinetic Mode. It will not be inunediately apparent in what sense Kinesis is an Energy in accordance with our definition : but, here again, the reader must courteously waive •?8 ABSTRACT OR ANALYTIC his objections for the present, and accept the state- ment provisionally, so far as he finds possible. Many difficulties of this sort necessarily beset the explana- tion of every new point of view, esj)ecially where previous misconceptions have clouded and embar- rassed the mental vision. Kinetic Energy is equivalent to motion. Any mass, molecule, atom, or electrical unit, in a state of motion, possesses Kinetic Energy. The subject may be con- veniently considered under the four heads hence aris- ing. But, just as before, when dealing with Energy generally, we found that we could not divide it into species so definite in their likeness as those of Force, because Energy was manifested in two Modes, the Potential and the Kinetic : so, here, when we are dealing with Kinetic Energy specially, we shall find that it cannot be divided into species so definite as those of the Potential Mode, because Kinesis itself is divisible into several Kinds, whose nature will form the subject-matter of the succeeding chapter. Molar Kinetic Energy is equivalent to the relative motion of Masses. It is seen in the fall of an unsup- ported weight or a spent cannonball to the earth. It is also seen in the rising of the ball, the flying of a bird, or the walk of a man. Again, it is seen in the orbital motion of the planets, and in the spinning of a top. THE MODES OF ENERGY 29 These various Kinds of Kinesis will be fully discussed in the next chapter. Molecular Kinetic Energy is equivalent to the re- lative motion of Molecules. It is found in the falling tofjether of Molecules of steam into water. It also occurs in the disruption of a cohering mass. And it is more conspicuous in the phenomenon of heat. Atomic Kinetic Energy is equivalent to the relative motion of Atoms. It is seen in that rushinjr to<Tether of Atoms which results in chemical combination. It also occurs in the severing of Atoms from the com- bined state. But it is not known to have any continuous form analogous to the orbital motion of a planet, the spinning of a top, or the regular vibration of heat. Electrical Kinetic Energy is equivalent to the relative motion of Electrical Units. It is seen in the lightning, in the discharge of a Leyden jar, and in the galvanic current. It will doubtless seem strange to the reader to find the motion of masses, molecules, and atoms towards one another spoken of as a manifestation of Energy : but this seeming inconsistency will be explained in the succeeding chapter. A table will clearly exhibit the relations here ft) described, one example only of each species being cited. 10 ABSTRACT OR AXALYTIC Enkrgies or Skparative Powers. Molav Poten- ' Molecular Po- | ^*!'7•° ^"^en. Potential J' tial Energy. | tential Energy, t'/il Energy. | Electrical Po- ' (Visible Energy! (Condensing Speciks of Position.) Molar Kinetic Steam.) (Chemical Energy of Free Elements.) Atomic Kinetic Vn^raxt Molccular I Energy. „. .. ,, forbffi Kinetic Energy.! (Chemical ^-;,-±?f;«y' tential Energy. (Tension.) Electrical (Orbital Motion.) (Heat.) Energy in Act of Combining.) (Galvanic Current.) 3» CHAPTER VII. THE KINDS OF KINKSI8. Motion has three Kinds, considered from our present standpoint. It may be separative, or it may be ao-crrecfative, or it may be continuous and neutral. Each species of Kinetic Enerfjy lias a form of each Kind. Molar motion may be separative, as when a can- non ball is shot up into the air ; or aggregative, as when the same cannon ball falls to the earth ; or continuous and neutral, as when a top spins in the same place. Molecukr motion may be separative, as in tearing asunder a mass; or aggregative, as in condensing steam ; or continuous and neutral, as in the case of heat. Atomic motion may be separative, as in decom- position ; or aggregative, as in the act of combining. The continuous and neutral stage is not at present known, thouijh there is reason to think that it exists. 32 ABSTRACT OR A XA LYTIC Electrical motion may be separative, as when the Positive and Negative Electricities are divided ; or ag- gregative, as when they are uniting. The continuous stage is possibly given us in the current which is sup- posed to circle round a magnet. It was noticed in the last chapter that there was an appearance of contradiction in the statement that aggregative motions were yet manifestations of Energy. That difficulty must now be met. When a cannon ball is shot up into the air, the motion is obviously separative, and there can be no doubt of its being a manifestation of Energy. Simi- larly, when a set of molecules are separated by mechanical Power or by heat, when a chemical com- pound is broken up into its elements, and when the Positive and Negative Electricities are sundered from one another, the separative nature of the process is obvious. We can have no hesitation in assigning each of these cases to the action of an Energy. But when we look at the continuous and neutral motions, their character as Energies is less obvious. A moment's consideration, however, wdll make it clear. The orbital motion of the planets is a continuous Energy which prevents them from aggregating with the sun as they would otherwise do. The motion of the top in like manner prevents it from falling on to the earth. The continuous vibratory molecular motion (or heat) THE KIXDS OF KINESIS 33 of the red-hot poker prevents the steam or the water particles from aggregathig into their cooled or liquid or solid states respectively. In short, whenever a body or molecule in a free state does not aggregate immediately with the other bodies or molecules which attract it, it is kept apart from them in virtue of some continuous or neutral movement.^ So soon as it parts with its Energy (or motion), it aggregates with the attracting body. Thus when the steam loses its heat it condenses into water ; when the water in turn is deprived of heat, it freezes into ice ; when the poker cools, it contracts ; when the top parts with its motion to the air on the surface, it falls ; and we have no reason to doubt that when the planets have dissi- pated their Energy of orbital movement by ethereal friction they will fall into the sun. This general principle — that free bodies can only be kept from aggregating by a continuous movement — is one of great importance, whose value will l)e seen here- after, A body in such a state of continuous move- ment, which prevents it from aggregating with another, is said to be in equilibrium mobile. Wlien, however, we come to the aggregative mo- tions, it would seem at first sight as though these ' The reader must be cautioned to notice the expression ' in a free state,' which exchides such instances as those of a weiglit tied bv a string, or a chemical body already in stable combination, whose case will be considered in the chapter on the Mutual Interference of Forces. D 34 A ns TRACT OK AAA LYTIC must be classed with Forces, not with Enei-f^nos. A considerable faculty of abstract thou<,dit is required to grasp their real relations : nevertlieless we must endeavour to solve the problem. In doing so, we must trench a little on the subject-matter of future chapters, but only by alluding to facts already familiar to the reader. When the cannon ball reaches ite highest point it possesses Potential Energy. But it does not remain suspended in the air. There are only two conditions under which it could do so, in opposition to the Force of gravitation : the first is if it is supported by a ledge or rope, in which case cohesion balances gravitation ; the second is if it possesses continuous kinetic energy, in which case it Avould circle round the earth as a satellite until its energy was dissipated. Practically, the existence of the atmosphere makes the second case purely imagi- nary within the limits of that medium, though it is exhibited in the ether by such a body as the moon. As the cannon ball does not fulfil either of these con- ditions, it begins at once to fall. But the Potential Energy which it possesses becomes thereupon Kinetic, from moment to moment, until, at the instant of touch- ing the earth, it has all assumed that mode. Now, we know that it does not then utterly disappear. The great principle of the Conservation of Energy teaches us that it is changed into the form of heat. Accord- ingly, while the two masses aggregate, certain mole- THE A'/.'\/)S OF AVA7:.S/.V 35 rules of cacli are separated ])y lieat. At the moment of roiitact, all the motion of the fall, or Aggregative Mo- lar Kinetic; Energy, is changed into heat (or separa- tive Molecular Kinetic Energy). There is just as much separation at last as at first : only when the ball was at its height, the separation was molar ; and when the ball has touched the earth, the separation is molecular. The formula which tells us how many heat-units are generated by the fall of such and such a mass through so many feet, is a formula for the equivalence of molar separation with molecular separation. ]hit in the intermediate time, during the fall. Potential Energy was disappearing every moment, and motion was taking its place. Though this motion was aggrega- tive, yet, when the ground was reached, it changed into the separation of heat. Accordingly, we are justified in regarding it as essentially a transitory form of separative Power. This will be still clearer if we take such a case as the moon's. That satellite, though attracted by the earth, is yet prevented from aggregating by its orbital movement. It possesses Potential Energy in virtue of its separation, but this does not assume the aggregative Kinetic form on account of the continuous orbital Energy. If, how- ever, we suppose the moon to have lost its orbital movement, still retaining its present position and size, it would at once yield to the earth's attraction, and all u-2 36 ABSTRACT OR AXALYTIC its Potential Energy would become Kinetic, When it reached the earth, the shock of its fall would reduce it to a very heated state, and an immense increase in size would result from the separation of its particles. The merely transferential nature of the aggregative motion is here clearly seen. So too, in the case of molecules. The Potential Energy of steam is given up when it condenses into water ; and the Potential Energy of water when it forms into ice. Similarly with atoms. When oxygen unites witli carbon and hydrogen in a candle, their Energy is yielded up in the form of heat, which produces a separation (or rarefaction) in the neighbouring atoms of the atmo- sphere. The same truth is shown in the heat and light evolved during the aggregation of Positive and Negative Electricities. Througliout we see that aggregative Energy is merely Potential Energy in the course of transformation to another form. While the really aggregative Power of Force is causing these bodies to combine, the Energy of tlieir motion repre- sents for a while their origmal separateness, and is finally transformed into a similar separateness between other bodies. A concrete instance will make this clearer. Let us suppose the case of a pulley, with a weight at each end, one suspended in the air at the utmost height of the pulley, and the other slightly hghter, on the ground. The heavier weight possesses Potential yy/A" A'/\DS OF KLMiSlS yj Energy in virtue oi' its elevation ; but, if it is free to act, it is drawn down by the aggregative Force of gravitation. In tliis case, however, all its Energy does not assume the Kinetic Mode as it drops : the greater part of it is used up in elevating the lighter weight to the same height, while the remainder chiefly goes off in the form of friction — that is, heat — that is, molecular separation. There is thus a mere fraction left to be converted into heat when the weight touches the ground; the mass of the Energy still remains Potential in the lighter weight. Here we see that the Energy of a falling body does not consist in its mere downward movement, but rather in that accelerating motion which is capable of being transformed into heat when the masses aggregate. If the motion be infinitely slow, the amount of heat evolved will be infinitesimal. So that the Energy of Kinesis is seen to be a mere transferential mode from one kind of separation to another. Acrain, we mav look at the similar in- stance of a clock, driven by a weight. Here the weight possesses Potential Energy, in the same way as in the case of the pulley ; but it has opposed to it, not another weight (that is, gravitation), but friction (that is, cohesion).^ As gravitation pulls down the ' Above we used friction in a different sense, as equivalent to heat. This is a necessary ambiguity of our present teruiiiiology. From the point of view of the Force involved, friction means the cohesion which must be overcome ; but from the point of view of the Enerfry employed, friction means the separative power of heat which o\ crcomcs 38 ABSTRACT OR ANALYTIC weiglit through each inch of its course, the Potential Energy so lost assumes the form of heat, or separa- tive Molecular Motion, in the wheels and bearings. When the weight reaches the ground, its Energy has all been used up, and the aggregative movement has been a real display of Force. Thus all I'le kinds of motion are ultimately shown to be forms of Energy or Separative Power. Kinetic Energies. Separative Aggregative-) Continuous Separative Molar Motion. I (In a body I raised from ! the earth's surface.) Aggregative Molar Motion. (In a falling body.) Continuous ' Molar Motion. I (In a top or a I j planet.) Separative Molecular Motion. (In a body torn apart.) Aggregative Molecular Motion. (In a body cooling.) Continuous Molecular Motion. (In heat.) Separative Atomic Motion. (In chemical decomposi- tion.) Aggregative Atomic Motion. (In chemical combination.) Continuous Atomic Motion. (Unknown.) Separative Electrical Motion. (In electrical machine.) Aggregative Electrical Motion. (In lightning.) Continuous Electrical Motion. (In magnet '?) 39 CHAPTEll VIII. THE PERSISTENCE OP FORCE. Every particle of matter has inherent in it certain Forces of which it can never be deprived. The total amount of Force or Aggregative Power in the universe is thus always a fixed quantity. This principle may be known as the Persistence of Force. It must be carefully distinguished from the opposite principle of the Conservation of Energy, to which the same name has been frequently but most incorrectly applied. Every mass tends always to attract every other mass, and cannot be deprived of this tendency. The tendency may be masked for awhile by the interven- tion of other masses, as when a loose stone stands on the top of a wall, or by the presence of an Energy, as when the moon circles round the earth, or a ball is shot from a cannon ; but it cannot be got rid of : for as soon as the stone topples over with the wind it falls to the ground at once; as soon as tlie ball parts 40 ABSTRACT OR ANALYTIC with its Energy it similarly falls ; and as soon as the moon has got rid of her motion by ethereal friction, she will aggregate with the earth. Similarly with molecules, atoms, and electrical units : every one of them when in a free state, un- restrained by interfering Forces, and unacted upon by Separating Enei-gies, rushes at once into a state of aggregation with its fellows. It is important to notice that Force, unlike Energy, is inherent and indefeasible in every unit of matter. It may be counteracted for awhile by an Energy, but it still remains ready to act so soon as the Energy is dissijDated ; it never passes from one unit to another, as we shall see that Energy does. Force, or. aggrega- tive Power, is the primary and indefeasible attribute of every material particle. 41 1 CHAPTER IX. THE CONSERVATION OP ENERGY. The total amount of Energy, Potential and Kinetic, existing in tlie universe is always a fixed quantity. It is not, however, like Force, rigidly bound up witl the individual particles in which it is from time to time manifested. As we have already seen, it can be transferred from one particle or set of particles to another. For this reason it has been deemed desirable to embody the principle in different language from that which we employed in the somewhat analogous case of Force. Wliile Forces persist. Energies are conserved. The concrete and practical results of this difference are enormous. It does not come within the scope of the present work to give a full account of the (juaiilitative rela- tions subsisting between the various species of Energy ; it will be sufficient to trace their equivalence in its broader (juaHtative aspect. For this purpose we may consider the phenomena of Conservation under three 42 ABSTRACT OR A XA LYTIC heads: tlie passage of Energy from the Potential Mode to the Kinetic, the passage of Energy from the Kinetic Mode to the Potential, and the passage of Energy from one species of the Kinetic Mode to another. Potential Energy or relative statical separation ^ has a tendency constantly to pass into the Kinetic Mode, under the influence of Force. Every free body or particle, unless restrained by an antago- nistic Force, or kept in separation by a continuous Kinetic Energy, is aggregated at once with other bodies or particles which attract it. A mass poised on a ledge or suspended by a rope is prevented from aggregating with the earth by the Force of cohesion ; but when some external Energy has pushed it off the ledge or severed the rope, its Potential Energy passes at once into the Kinetic Mode, under the influence of gravitation. Two molecules of water vapour are prevented from aggregating under the relatively feeble attraction of cohesion at a distance by their inertia — that is, by the relatively strong cohesion of surrounding or intervening mattei's (just as a mass ' By this term is implied a separation which, though perhaps accom- paiiietl by actxial motion, does not carry the two related bodies further iway from one another. Thus, orbital motion in a perfect circle, or the upright spinning of a top, is statical relatively to the centre of gravity of the system ; while a fresh energy would be reipiired to carry the related bodies further away from one another. THE CONSERVATIOX OF EXERGV 43 Oil the table, tliou^li attracted by the earth, is pre- vented from aggregating by the intervention of tlie cohering boards)— but when some external Enei-<>v brings them within such a distance of one another that the resistances are overcome by their mutual attractions, their Potential Energy becomes Kinetic, and they aggregate with one another. Two atoms (having affinities for one another) are similarly prevented from aggregating by inertia ; but when brought within the sphere of their mutual attraction, their Potential Energy becomes at once Kinetic, and they combine with one another. So also, two electrical units are prevented from aggregatin^r in the Leyden jar by the electrical neutralitv of the Hass partition ; but when a conducting medium is made to connect them, their Potential Energy passes into the Kinetic Mode and they rush together at once. Kinetic Energy "or motion often passes into the Potential Mode. The Kinetic Energy of actual separa- tion always exhibits this interchange. A cannon ball fired in the air, the piston of a steam-engine forced 'up by the expansive Energy of the steam, a weight hauled by a pulley to a height, a man who has climbed a mountain, are all of them instances where Molar Kinetic Energy has become Poten- tial. The liquid condition of water melted from ice, the diflused state of vni)our raised from water, ai-e 44 ABSTRACT OR ASA LYTIC instances where Molecular Kinetic Energy has become Potential. The free hydrogen and oxygen of an electrolytic bottle, the iron and oxygen driven from their combination by heat, are instances where Atomic Kinetic Energy has become Potential. The negative and positive electricities of a Leyden jar, of a thunder- cloud and the earth, of the knobs of an electrical machine, are instances where Electrical Kinetic Energy has become Potential. Finally, Kinetic Energy often passes from one of its species to another. Molar motion passes into Molecular motion whenever one mass interferes with the motion of another. This is true whether the motion is aggregative, or separative, or continuous. If a cannon ball be allowed to fall to the earth from a position of Potential Energy, all the Kinetic Energy which the mass acquires in its fall passes to the molecular species when it touches the ground. If it be fired into the air, and immediately checked by an iron target, the same result occurs. And if a top be stopjjed in spinning or the moon checked in her course, exactly like effects are or would be pro- duced. Molecular motion passes into molar motion whenever the free separation of the moving molecules is interfered with by the cohesion of enclosing masses. Thus the steam in a cylinder pushes up the piston by its expansion ; the freed nitrogen in a discharge of THE COXSERVATION OF KXERGY 45 gunpowder in like manner puslies out tlie ball ; and tlie energetic movement of a heated gas bursts the vessel within which it is confined. Molecular motion also passes into atomic motion in decomposition by heat, and into electrical motion in the friction macliine. Atomic motion passes into molecular motion wlien heat is generated by chemical combina- tion. It also passes (apparently) into electrical motion in the galvanic current. Electrical motion passes into molecular motion when an interrupted current produces heat. Light, which is a phenome- non connected with the ethereal medium, must be neglected for the present. This relation is quantitative-that is to say a defimte amount of Potential Energy passes always into a definite amount of Kinetic, and vice versa whde a definite quantity of each species is equivalent to a definite quantity of each other species, in either Mode. The law of conservation may therefore be subsumed under the following formula, where A stands for Potential and B for Kinetic Energv 1 2 3, and 4 for the Molar, Molecular, Atomic, ^md Elec- trical species, and 5 for the Kinetic Energy of the ether (of which more hereafter) : Al.A2.A3.A4.Bl.B2.B3.B4.B5 = aconstant quantity. But While the total of Energy, like the total of lorce, IS thus constant, the total of each mode and 46 A US TRACT OR AXALVT/C species varies from moment to moment. Wliereas tlie total of each Species of Force is as constant as the sum of their totals. Again, while each unit of Force is rigidly bound up with each atom of matter (with which it is perhaps identical),^ each nnit of Energy may pass from one mass, molecule, atom, or electrical unit to another. It may also pass from matter to the ethereal medium, and vice versa. This can only happen, however, to Energy in the Kinetic Mode. A mass in motion parts always with portions of its motion to all other bodies with which it comes in contact. It does so either by imparting to them a portion of its motion in the molar form (as when one billiard ball strikes another), or in the molecular form (as when heat is generated by friction). Hence every moving mass tends to part with all its Kinetic Energy more or less (quickly, according as it is more or less impeded in its motion by more or less cohesion and gravitation. Thus a cannon ball parts with all its Molar Kinetic Energy at once when it strikes an iron target, and very quickly when it is fired in the air ; a bilhard ball parts with it more slowly, as it hits the other balls and the cushions ; a quoit on ice 1 It is possible to regard each atom as a centre of Force (i.e. Aggre- gative Power) liable to separation from other centres by means of Energies (i.e. Separative Powers). THE COXSERVATFOX OE EXERGY 47 more slowly still, as it meets the resistance of the air <and the <rentle friction of the ice ; while a pendulinn under an air pump hardly parts with it perceptibly by friction on its knife-edge, and a planet only by in- finitesimal decrements to tlie ethereal medium. ' A molecule in motion parts similarly with a portion of its motion to every other molecule with which it comes in contact. When the two molecules, however, possess equal motions, or, as we oftener say, are at the same temperature, the amounts of gain and loss neutralise one another. J^ut when the motions of the Molecules differ, the more energetic parts with a disproportionate amount of its motion to the less ener- getic, until the Energies of both are equal. Hence it happens that whenever the molecules of any mass have a higher Kinetic Energy than that of surround- ing bodies, the motion of its molecules is imparted to the surrounding bodies till a state of equahty is reached. As to Atomic and Electrical motions, we know too little of their nature to speak with any con- fidence, but we see at least that they also tend to pass away from the bodies with which they were as- sociated, and to assume the forms of light and heat. Li short, without fully anticipating the chapter on the Dissipation of Energy, we may say that whenever masses, molecules, atoms, or electrical units are free to act in accordance with their aggre- 48 AD SIR AC I OR A XA LYTIC gative tendencies, witliout interference of antafjonistic Forces or restraining power of continuous Kinetic Energies, they innnediately unite, and impart their former Potential Energy in the Kinetic Mode directly to surrounding bodies, and ultimately to the ethereal medium. We may thus sunmiarise the contents of the pre- sent chapter : the sum total of all Energies in the Universe is a constant quantity ; and whenever one mode or species of Energy disappears it is replaced by an equivalent quantity of another mode or species. 49 CTIAPTER X. TIIK INDKSTKUCTIBILITY OF POWER. TiiK two generalisaiions briefly stated in the two preceding chapters under the titles of' The Persistence of Force ' and 'The Conservation of Energy ' may be sunnned up under a still wider generalisation to which we shall apply the title of ' The Indestructibility of Power.' It may be formulated as follows. The total amount of Power, aggregative or sepa- rative, in the Universe, is a constant quantity, and no Power can ever disappear or be destroyed.^ This short chapter cannot be enlarged by the addition of any further remarks. Like our first chapter on Power generally it does not admit of am- plification. ' Readers of Mr. Herbert Spencer's System of Synthetic Philosophy will doubtless observe that it is tliis ultimate generalisation to whicli he refers under the style of the Pcrsistenre of Force, and not either of the minor {generalisations subsumed under it. The author, however, makes this statement solely on liis own responsibility, and has no warrant from Mr. Spencer for doing so. It is not improbable that Mr. Spencer would energetically dissent from acquiescence in tlic slate- ment. . . ...... , B so ABSTRACT OR ANALYTIC CPIAPTEE XI. THE MUTUAL INTERFERENCE OF FORCES. As tlie various portions of matter, molar, molecular, and atomic, all possess Forces of their own, it must necessarily happen that many bodies or particles are attracted in different directions with varyin^y intensities by surrounding bodies or particles. Hence arises a certain cross-attraction or Mutual Interference of Forces. We shall consider in regular order the various modes in which each species of Force is opposed by interfering Forces. Molar Force may be opposed to another Molar Force when two neighbouring masses each tend to attract a third mass. If all three masses be in every respect free — that is to say, if there be no other re- straining Force, and no continuous Energy of relative motion — the three masses will aggregate simply. But in the large planetary bodies exposed to our observa- tion the orbital Energy counteracts all the Forces ; and we consequently see the sun, the earth, and the moon retaining their relative positions in spite of THE MUTUAL INTERFERENCE OF FORCES 51 gravitation. There are certain instances, however, where the interference of Forces is seen, even in the case of Mohir Forces. Thus, a hirge body like a table does not perceptibly attract even very small bodies on the floor, owing to the superior Power of the earth's attraction as a whole. Yet in the neiirh- bourhood of much larger masses, such as mountains, a slight deflection of the plummet has been observed, because the attraction of the mountain has proved strong enough to counteract in part the attraction of the earth as a whole. Molar Force is more commonly interfered with by Molecular Force or cohesion. A weight placed on a table or a ball suspended by a cord cannot aggregate with the earth generally, because the Force of gravita- tion is overpowered by that of cohesion. At a certain point, however, the Power of gravitation outweighs that of cohesion, and the tal)le or the rope gives way. We can scarcely say with any certainty that Molar Force is interfered with by Atomic and Flec- trical Forces : but there seems no reason to doubt that chemical attraction may act in opposition to gravitation by causing an atom to aggregate with an- other atom so as to raise it slightly above its previous level: while tlie position of a lump of iron sus- pended from a magnet (permanent or electro-mao-- netic) probably represents the interference of electrical K 2 52 ABSTRACT OR ANALYTIC with molar Force. Our acquaintance with these phe- nomena, however, is so very superficial that it would he premature to do more than hint at possible ana- logies. Molecular Force may be opposed by Molar Force in the above-cited instances of a mass laid on a table or hung by a cord. If the Molar Force overpowers the Molecular, the table or cord breaks, and the mass falls to the ground. One Molecular Force is op- posed by another Molecular Force in the curious case of what is called Molecular Tension. In such an in- stance, certain molecules on either side of a particular set of molecules tend to draw it towards them, and the stronger attraction finally succeeds in doing so, leaving a disrupted portion on one side of the line. Molecular Force is probably opposed by Atomic and Electrical Forces, though here again no very obvious instance can be cited. Atomic Force is possibly opposed by Molar Force as noted above. It is also possibly opposed by Molecular Force ; and this seems not improbable when we recollect that many bodies will not combine chenucally unless at a high temperature — in other words, unless their Molecular Force has been coun- teracted by an antagonistic energy. One Atomic Force is certainly opposed by another Atomic Force when two diflerent atoms, each having afiinity for a THE MUTUAL INTERFERENCE OF FORCES 53 third atom, are brought into close conjunction with it. This occurs in all ordinary reactions ; and, as we see, the stronger affinity overpowers the weaker one. What may be the relations of Atomic to Electrical Force it would be premature even to guess. Electrical Force as a whole is too little understood to permit of definite treatment. We may conjecture, however, that it is similarly nifected with other Forces. In one case, at least, we c:vi feel sure of an analogy. One Electrical Force can b^ opposed to another by placing two balls, pretty equally charged with Posi- tive Electricity, opposite io (^ne another, and at equal distances from a ball charged with Negative Elec- tricity. In this case we set I'p a state of cross-tension like that of the interfering masses, the molecular tension, or the rival chemical affinities : and any slight diffi^rence in the two attractions will cause the one to outweigh the other. It would also seem as though, in the case of a Leyden jar, the molecular Force of the glass opposed the Electrical Force whicli tends to aggregate the opposite electricities : for when the Electrical Force reaches a very high pitch, the electricities escape from some point on the metal surface, and leave a hole pierced through the glabs. The analogy of this case to that of the broken rope or table is obvious. On the whole, however, the •54 ABSTRACT OR ANALYTIC subject is still too ill-correlated with other depart- ments of physics to allow of positive statements. In all the cases where the interference of Forces produces an actual separation between masses or particles previously in (relative) contact, it might at first sight seem as though there were really an exhi- bition of Energy and not of Force. As in the case of aggregative Energies, however, a little consideration will correct this idea. For the bodies always follow the stronger Force ; and the result is, a total of closer and more intimate aj?2^regation than that which before subsisted. If the cord can resist the power of gravi- tation, then the union between its molecules is a more intimate one than that which would result from the aggregation of the ball and the earth. If, on the other hand, the cord cannot resist it, then the total of ag- gregation is increased by the fall of the ball. So, too, if a body in chemical combination with another body can resist the afFniity of a third body brought near it, the existing union is shown to be a closer one than that proposed for it. If, on the other hand, it cannot resist it, then the new union proves itself thereby to be closer and more intimate than the previous one. When we come to consider the material universe as an aggregating total, whose separative Energy is being imparted to the ethereal universe, this point will become much clearer. 55 CHAPTER XXL THE SUPPRESSION OF ENERGIES. When a set of particles possessing Kinetic Energy is entirely surrounded by other particles, bound together by Eorce, it is possible up to a certain limit to sup- press the Energy of the contained particles by Umit- incT their mutual movements ; whereupon the Energy appears to exist in a dormant state. But when a certain point of suppression is reached, the Energy of the contained particles overpowers the Eorce of the containing particles, and a disruption takes place. Such a disruption is commonly known as an Explosion. Or again, at a point short of disruption, such an active separative impulse exists amongst the contained particles, that if any aperture be made in the con- taining wall, the contained particles rush out with Explosive Energy. The abstract statement of this principle must be enforced by a few concrete examples. The boiler of a steam-engine is a wall or partition 56 ABSTRACT OR ANALYTIC of molecules, rigidly bound together by cohesion. Within it, is a mass of water and steam, which is being raised to a high pitch of molecular motion by the fire underneath. Up to a certain point, it is possible to sujipress or restrain the separative Energy of the steam by opposing to it the cohesi^^e Force of the iron wall. But when a certain point of suppression is reached, the Energy outbalances the Force, and an Explosion takes place. At a point short of the Ex- plosion, it is possible to open a valve and ' blow off steam ' : the energetic particles then rush forth with Explosive Energy. Similarly when a gas is reduced by pressure to the liquid state. Up to a certain point the Energy of the gas is suppressed ; but when that point is passed, the Energy outbalances the Force, and an Explosion takes place. Short of the Explosion, it is possible to open the vessel, whereupon the gas rushes forth with Explosive Energy. It is possible that certain (so-called) chemical com- binations are really of this nature. Thus, certain compounds of nitrogen are very apt to explode, and it would seem not unreasonable to suppose that in their case the Energy of the free gas may be in some way confined by the combining atoms : while a match or other detonating agent may be the analogue of the valve or the stopcock in the above cited cases. This THE SUPPRESSION OF EAERCIES 57 possibility will be more fully discussed in tlie succeed- ing chapter. It is important to notice that one Energy may be opposed to another in producing a suppression. Thus Energy is expended in compressing a gas or bending a bow (a case which will be fully considered here- after). So that just as Forces interfere with Forces, Energies sometimes oppose Energies. A suppressed Energy is regarded in the ordinary text-books as Po- tential. It is clear, however, that it cannot be so re- garded from our present standpoint. It is essentially Kinetic, though its Kinesis is masked by surrounding bodies. 58 ABSTRACT OR ANALYTIC CPIAPTER XIII. LIBERATING ENERGIES. When any body or particle possessing Potential Energy is prevented from aggregating with any other body or particle which attracts it, by the interference of an antagonistic Force, its Energy can only assume the Kinetic Mode through the intervention of some external Energy. Such external Energy is itself necessarily in the Kinetic Mode. It is known as a Liberating Energy. Put in more concrete language, this principle may be otherwise stated thus. A body can only be dis- engaged from the attraction of one Force and brought under the direct influence of another, by some move- ment affecting it. A moment's consideration will make it clear that this is a corollary from previously stated laws. As we saw that the stronger Force necessarily out- weighs the weaker, and as Forces cannot increase or decrease in intensity, the only manner in which any • LIBERATING ENERGIES |^ body or particle can be released from the Force which actually governs it and brought under the in- fluence of another Force, is bv some movement which either severs it from the sphere of the existing Forces, or brings it within the sphere of a stronger one. In the latter case, it is immaterial whether the movement brings the body into proximity with other bodies, or brings other bodies into proximity with it. Molar Liberating Energies are those which release masses from the interference of a Force antagonistic to gravitation. The commonest instance of such a Liberating Energy is seen when we remove some obstacle which by its cohesion prevented the aggre- gation of gravitating massec. Thus a ball suspended by a thread is released by the separative Energy of a knife or scissors. A clock weight wound up but checked by a catch, is released through the Energy which removes the catch. A stone perched on a ledge is released by the puff of wind or the blow from a hand which causes it to topple over. A head of water confined by a sluice is released by the Energy which raises the sluice. A mass of ice on a mountain top is released by the Energy of heat, which breaks down the co- hesion of its particles and allows it to trickle down the sides. Even in those cases where the intervention of the Energy is less apparent, we can see in an ultimate analysis that such Energy is really the moving ^ ABSTRACT OR ANALYTIC Power at work. Tims, when the string decays instead of being cut, it might seem at first sight that the co- hesion mehed away imperceptibly ; but a closer con- sideration will show us that the dropping of water, the action of liejit and light, the approach of chemical solvents in minute quantities, and the incidence of other unobserved Energies is really the cause of the decay. So, too, if the water makes a way through the sluice, or cuts a path for itself through the bank, it can only do so by the slow action of incident Energies, which wear away the cohering substance that retains it. And the stone can never topple over from its ledge unless some animal pushes it, or some slow water action wears away its sui)porting mass. Molar Liberating Energies may also be seen in a few cases where a chemical body undergoes a separation which precipitates the heavier among its constituents. Molecular Liberating Energies are those which release molecules from the interference of a Force an- tagonistic to cohesion. Two planed pieces of iron cannot cohere if laid side by side on a table : they are restrained in their places by gravitation. But the energy which apposes them to one another acts in this case as a liberator. Li other instances, heat performs the same function, by loosening cohering molecules from their existing arrangement, and bring- ing them within the sphere of their mutual attractions, LIBERATING ENERGIES ^i as wlien we weld two pieces of iron by heating them, or by hanuneriiig them together. Tlie contained energy of water fulfils a like office in gumming or glue- ing, and in mixing plastic clay or dough. In these cases, one cohesion has interfered with another, and t .e Liberating Energy, by causing a partial disengage- ment, finally permits the complete saturation of both affinities. Atomic Liberating Energies are those which release atoms from the interference of a Force antagonistic to Chemical Affinity. Occasionally it is the mere Force of gravitation or cohesion which opposes this affinity, and in that case, the Energy employed in bri'.ging the substances together is the liberating agent ; as when we expose phosphorus to Chlorine. Li other in- stances, however, the mere apposition of the elements is not sufficient, as when we expose carbon to oxygen ; heat is then needed as a liberating agent ; and we may conjecture that it acts by setting up such a molecular vibration in the carbon as takes each atom out of its existing stable arrangement with other like atoms, into a compound carbon molecule, and brings it within the sphere of the stronger affinity exerted by oxygen. This case leads on to those where the in- terference is between rival Chemical Affinities. The Energy which brings together two substances and per- mits the stronger affinity to overcome tlie weaker acts 62 ABSTRACT OR ANALYTIC as a liberating af^ent. In this instance, too, lieat is sometimes necessary as an additional factor, probably for the same reason as before. In the case of CI and 11 light acts as the liberating energy. Other less obvious cases resemble those of a match, where' fric- tion performs the same function. Electrical Liberating Energies are those which release Electrical Units from the interference of a Force antagonistic to Electrical Affinity. The usual vagueness of electrical science prevents any definite treatment of these phenomena ; but we may consider the Energy which closes the circuit of a battery, or brings the discharging tongs to a licyden jar, as essen- tially analogous to the cases noted above. Their fun- damental similaritv will be seen if we recollect that any Energy spent in overcoming the cohesion of the glass partition in the Leyden jar, and so causing it to break, would produce exactly the same effect.^ Under the head of Liberating Energies it will be ' The practised physicist will observe that a much wider significa- tion is here given to the term Liberating Energy than that which is usually attached to the expression ' Liberating Force ' in the current phraseology of science. But if, as here contended, the cases are really analogous in every way, then there is no logical reason why they should not all be included under a single general name. Of course, if com- petent critics can point out any error in the conception here advocated, the classification falls to the ground ; and throughout, it must be re- membered that all the ideas contained in this treatise, though dog- matically stated for simplicity's sake, must be regarded merely as suggestions and points-of-view thrown out for the express purpose of placing the author's conception in a clear light. LIBERATING ENERGIES 63 convenient to include those other Energies wliich act so as to permit tlie escape of suppressed Kinetic Energies. Such will be the Energy which turns the valve of a steam-engine or the stop- cock of a vessel containing compressed gases. A more familiar in- stance is found in the Energy which draws the cork of a champagne bottle. And if we were correct in supposing an analogy between known suppressed Energies and explosive nitrogenous compounds such as gunpowder and nitro-glycerine, then the match or blow which explodes them acts as an analogous liberating agent. Liberating Energies of this des- cription may be conveniently described as Liberators of Suppressed Energies. 64 ABSTRACT OR ANALYTIC CHAPTER XIV. MISCELLANEOUS ILLUSTRATIONS. After so long and so abstract an exposition, it may be well to give a few selected conciete illustrations, showing the interaction of the principles already laid down, before we proceed to those still more abstract and difficult problems which yet lie before us. We have liereafter to frame some clearer notion of the Relation between Ether and Matter, the Nature of Energy, and the Nature of Movement ; which questions will require a power of abstract thought and concentration which is not possessed by every reader. But it may aid our comprehension of these highest abstractions if we more firmly grasp the concrete phenomena in which they are dimly mani- fested. A lump of ice lies loosely on a mountain top. Its molecules are rigidly bound together by the Force of cohesion. The Force of gravitation tends to attract it, but the cohesion of intervening molecules interferes, MISCELLANEOUS ILLUSTRATIOXS 65 and it car not further aggregate, cannot get any lowei . of its own accord. It j^ossesses Potential Energy in virtue of its separation from tlie dead level of ocean : but that Energy cannot assume the Kinetic Mode so long as the interfering Force of cohesion prevents it. There are, however, various conceivable wavs in which a Kinetic Energy may intervene to liberate it. Tlie wind may blow it over ; a man may hit it with I is stick ; or a peal of thunder may shake it down. Li any of these cases, it will go down as a mass, all its molecules still locked together by cohesive Force. Again, the Kinetic Energy of ether (which we commonly know as Eadiant Heat) may foil upon the mass, while still perched on its pinnacle. In that case, the motions of the ether particles will be com- numicated to the ice molecules, just as the motion of one billiard ball is communicated to another — or still more exactly, as one pendulum might set another in synchronous motion by striking it time after time. Under the influence of this separative Power, the molecules will slowly be unlocked from their cohesive union, and the ice will be melted. V>wi the Enerfv wliicli thus acts as separative to the molecules in their relation to cohesion, acts also as li])orative in their relation to gravitation. The Potential Energy of each molecule (visible Energy of i)osition) now- becomes Kinetic, and tliev roll down the mountain F 66 ABSTRACT OR ANALYTIC side iv! ilie form of water. Let us suppose that they unite ou their course and make a cataract. When they reach the level below (which for vcc^w- ment's sake we will suppose to be that of the sea) all their Potential Eneroy has been transformed into Kinetic. Omitting the small amount lost ^)y friction on the way, this Kinetic Energy is immediately trans- formed once more, as the water reaches the surface, from the Molar to the Molecular species. It becomes heat, and is radiated off into the surrounding space. Our ice has thus entirely parted with its Potential Energy to iieighl curing bodies, and to the ethereal medium, though the water which represents it still holds all the Kinetic Energy which originally melted it. It cannot again be raised to the mountain top without the integration of fresh Energ}\ Whence is this to come ? In the majority of cases it is supplied by the Padiant Heat of the sun. This Energy, work- ing upon the surfiice of the sea, causes separation amongst its superficial molecules, which thereupon rise into the air. Thus we see that the same Energy which overcomes the ftiint cohesion of the water also overcomes in part the force of gravitation. The heated molecules, being less attracted than the colder, are pushed upward by their pressure, and rise to a considerable height. The agent in raising them is Energy. So that tlie very same motion which keeps MISCELLANEOUS ILLUSTRATIONS 67 the planets from aggregating with the sun, keeps the water molecules from aggregating with the earth. So long as they retain this Energy they continue to float at a great height. But they cannot retain it long. The surrounding objects at that height are very cold — in other woi'ds, are not in a state of high molecular vibration. Accordingly, when the molecules encounter a cold mountain top, towards which they are attracted by molar Forces, they part with their heat and ao-<rre<xate under the influence of cohesion into ice. Their Kinetic Energy is now all gone, and nothiufr remains to them but the Potential Euergy of their separation from the level of the sea. And then the whole cvcle of changes beo-ius over aL^ain. Let us look next at a totallv different instance, that of a cross-bow. This is a common illustration with physicists, and it has already been once hinted at, but no detailed explanation was given, because it will be presently seen that the case is much more com- plicated than at first sight appears. The Kinetic Energy of humaii muscles is employed in pulling the string back to the notch. The bow is then bent. Now this l)ending implies two forms in which the energy becomes dormant, which answer to the connnon expressions, tension and 'pressure. The molecules in the convex portion of the bow are pulled slightly apart from one another, but not beyoiul the sphci'c of 68 ABSTRACT OR ANALYTIC their mutual attractions. We have consequently here a state of Potential Energy due to the separation of particles strongly influenced by cohesive Force. The molecules in the concave part of the bow, on the other hand, are pressed closely together upon one another by the Energy employed, which here acts in opposition to the Kinetic Energy of the molecules, whose natural vibrations are thus in part suppressed. Accordingly we have here a state of suppressed Energy. Both of these of course tend to become Kinetic, but are prevented by the interfering cohesion of the string and the trigger. The separative nature of the Energy employed is clear from the fact that if the string is pulled too far back, the strain upon the cohering particles becomes too great, and the sphere of their mutual attraction being transcended, they break apart with a snap. In the present case, how- ever, having merely bent and bolted our bow, we have all our Energy bottled up in a dormant state. Next, let us release the string. The Energy which we employ in doing so, acts as a I^iberating Energy with reference to the Potential Energy of the convex part, and as a Liberator of Suppressed Energy with reference to the concave part. It removes that cohesive obstacle, the trigger, which interfered with the mobilisation of the dormant Energies. The Molecular Force of cohesion now draws together the MISCELLAXEOUS ILLUSTRATIOXS 69 separated molecules of the convex part, and their Potential Energy becomes Kinetic. Through the medium of the string it is comnmnicated to the arrow. The arrow flies rapidly through the air, parts with a small portion of its Energy by friction, but retains most of it till it pierces the target. Here, part of its Energy is used up in producijig separation between the particles ; while the remainder is given off" in the form of heat. And so all our Energy is once more yielded up from its original possessor, the bow. Again, let us take a case where chemical activity is concerned. A lump of coal possesses Potential Energy in the separation of its atoms from those oxy- gen atoms towards which it is attracted by Chemical Affinity. So long as they are merely in mechanical conjunction with one another, the interference of some other Force (probably cohesion) prevents tliem from aggregating. But when a Liberating Energy is applied in the shape of a match, the atoms rush together in a mutual embrace. Their Potential Energy becomes Kinetic, and they aggregate. But the Energy of their separation is not destroyed. It is conununi- cated to the ether as Eadiant Heat. In this f tate it may either pass aw^iy from our earth altogether, or it may be communicated to other bodies, in which case it is said to be ahsorhed. Let us suppose it is absorbed by a boiler of water. The water molecules 70 ABSTRACT OR ANALYTIC are then thrown into a state of vibration, wliicli rapidly severs tlieni from one another until they assume the form of steam. If this steam is allowed to issue from the boiler, it will rapidly give off its Energy to neighbour- ing bodies, the ether inchided, and the Energy which first passed from the coal and oxvgen to the watei-. will now pass from the water to the ether. Ihit we may use the boiler to turn an engine. In this case part of the Molecular Kinetic Energy is trans- formed to the Molar species in the piston. It is then used up in initiating movements in the wheels and cranks, all of which are finally retransformed into the Molecular Species by friction. If the engine is sta- tionary, the friction will be between its parts ; if loco- motive, between its parts and the rails. Ultimately, in every case, all the Energy is yielded up to the ether in the Kinetic Mode and radiated off into space. Now what is the conclusion which all these cases force upon us ? That whenever Forces succeed in a^-- gregating masses, molecules, atoms, or electrical units, the Energy of their separation, passing into the Kinetic Mode, is transferred to surrounding bodies, and after many or few vicissitudes is finally handed over to the ethereal medium. This is the point which must next engage our attention. 71 WIAPTER XV. THE DISSIPATION OF HNEROY. IiN the defiuitiou of Force given in our sfoond chapter, a Force was stated to be a Power which initiated aggregative motion and resisted separati^'e motion in two or more particles of ponderable matter, and possiljly also of the ethereal medium. In the definition of Energj-, given in our third chapter, an Energy was stated to be a Tower which initialed separative motion and resisted aggregative motion in two or more particles of ponderable matter or of the ethereal medium. This addition in the latter case, and its qualified omission in the former, was intentional and significant. Though we caniiot dogmatically say that the ether does not possess Forces, we do not know it to possess any ; and if it does, the resistance which they offer to separation appears to oe almost infinitesimal. It may well be that ether is merely a more tenuous kind of matter, animated by the same Tower as the ponderable lK)dies : but vwn if i( is. we know that it 72 ABSTRACT OR AXALVTIC can Ije coiispicuoiisly affected l)y Eiier^^y, wliile we do not know tliat it can be conspicuously affected l)y Force. ^ From this difference flows a very im- portant corollary which may be formulated as follows. The Energy li])erated from the Potential Mode when bodies or particles aggregate under the influence of Force tends ever to assume the Kinetic Mode, and to be transferred from ponderable matter to the etliereal medium. As Liberating Energies are peri)etually setting free Potential Energy, and permitting aggregative motions to be set up under the influence of Force, and as the Kinetic Energy thus liberated is transferred to adjacent bodies, a part of it at least must be transferred to the ether. Furthermore, as that part of it which is trans- ferred to the ether is radiated off in everv direction into space, it must happen that the greater part of it is lost for ever to ponderable matter, and imparted to the ethereal medium. For, although some portion of the Energy may riieet in its course with ponderable matter, and be absorbed thereby, yet inasnaicli as the interstellar spaces are vastly larger than the inter- spersed ponderable heavenly bodies (so that in most ' The mere fact that motion can be lost by ethereal friction, as we know in the case of heated molecules and believe in that of planetary bodies, would lead us to suppose that the ether has something rosem- bUng cohesive Force. THE DISSIPATIOX OF EXERGY 73 directions motion may be continued in a straight line for ever without meeting one) it necessarily happens that the greater portion will never meet with any ponderable matter, but will go on, presumably ad 'uijinitum, traversing the ethereal medium. This principle, which will be i'ully expounded in its con- crete aspect in Part II. of this work, must at present be accepted in this its abstract aspect, on the ground here laid down. Again, though nuich radiant Energy may fall upon any one mass from another (as on the earth from the sun), yet inasmuch as this Energy is the cor- relative of an aggregation wliich has taken place in the radiating mass, whereby some of its Potential Energy has become Kinetic and been imparted to the ether, and inasmuch as the portion absorbed by that l)articular mass bears an infinitesimal ratio to the portion radiated ad infinitum, it must follow that on the whole every aggregation involves a loss of Energy to ponderable matter and a gain of Energy to the ethereal medium. Once more, even that portion of Energ}' which is absorbed by any other mass will in part be used up in Liberating Energies (as when solar heat melts a piece of ice on a mountain top), and will accordingly itself be a cause for future transfers of Energy from ponderable matter to the ethereal medium. And finallv, this 74 ADSIRACT OR ANALYTIC absorbed Energy itself will in part iit least be radiated oir from the absorbing mass and imparted once more to the ethereal medinm. We thus see in every case that all Energy lends to be lost by i)onderable matter and transferred to the ethereal medinm. CHAPTER XVI. TIIK NATURE OF EXKKGY. We now come to the most abstract and fun(lamenl;il question of all. What is the true nature of Energy ? In the beginning of this book we took it for granted that Force was equivalent to Aggregative Power and Energy to Separative Power. Tliat first assumption, however, is in reality the point which our treatise is meant to prove, and we have tried to prove it by running through the chief manifestations of Power and showing how simply and truthfully they can all be fornnilated on this principle. We have en- deavoured, in other words, to point out the perfect congruity of our assumption with fact. Having done so first in the abstract, we shall proceed to show how the phenomena which form the subject- matter of the various sciences, and how the concrete course of events in the universe, can be expressed in terms of our formulae. But before we go on to these departments of our subject, we must try to gain a clearer conception oi the real nature of Energv. 76 AliSTKACT OR AXALVTJC Energy is Separative Power. Every Energy in the Universe was primordially a mere statical separation of masses, nioleeiiles, atoms, or electrical units. If there were no such i)owei as Force, every one of these bodies would have remained for ever apart and im- movable. But as forces draw together these nuitually attractive material objects, their Energy assumes for a moment the Kinetic Mode. The falling water, the movinj' «jlacier, the oxv^en rushinj; to unite with the coal, each pass for a shorter or longer period through the Kinetic stage. As they aggregate, their Energy is given off in some other form of motion, involving separation. Hut as they move about, they part with this motion in separating other masses or molecules, and the attractive Force soon brin<;s them together ajjain. And what is the meaning of the Law of Conserva- tion ? Simply Uiis : that the total of statical separa- tion, plus the total of motion, in all particles what- soever, material or ethereal, is always a constant quantity. In other words, separation can never yield to aggregation without generating an equivalent amount of motion, which itself may pass into separa- tion of some other sort: while, conversely, motion can never cease without generating either an equiva- lent separation or an equivalent other motion. Thus a body at a heigiit cannot fall without generating an amount of motion proportionate in a known ratio to its mass and height, which motion itself is transferred THE NATURE OF ENERGY 77 on the body's fjill to its several moleeules, ciusing a separative action aniongtliem; and tliis motion is again transferred to the ether : while, similarly, a piece of coal cannot combine with oxygen withont yielding np its separation in the form of molecular motion, which motion may raise vapour of water to a considerable separation from the earth's central mass, and be itself finally yielded up to the ether. In short, the alternative Modes of Energy are Actual Separation, and Motion which eventuates in Separation. Furthermore, no body can be prevented from saturating its aggregative tendencies except by an Energy. There is no known way in which the total of bodies can be kept apart from their closest con- junction with one another except by continuous motion, like that of a planet, a lop, or a vibrating molecule. Even the case of Interference of Forces, which at first sight seems an exception, is not really so (though for convenience' sake we have treated it as such), because to suppose that the suspended ball will break its string or the weight push through the table is to suppose that a weaker aggregative tendency will overpower a stronger one. In all the laiger bodies of the Universe we see the discrete state main- tained by orbital Energy : and in all the molecules of liquids and gases on this earth we see the discrete state maintained by heat, or contiimous vibration. 7« A nS TRACT OR AXA LYTIC CHAPTER XVIT. TUB XATURB OF MOTIOX. Last of all conies the question, — What is Motion F Divesting our minds of all concrete associations and locking at the phenomenon in itself, we arrive at the following unfamiliar conclusion. Motion is the ^Nlode by which Energy (or Separa- tion) is transferred from one portion of matter to another, and ultimately from matter, to the ethereal medium. Wlien the Motion is simply separative we see this in a moment. A ball fired upward, a weight carried to a height, or an atom disengaged from a compound, sliow us motion as ecpiivalent to separation, in its naked form. When we look at Motion along a line at equal distances from the attractive centres — as in the case of a locomotive running along a level — we do not at first see how the Energy can be con- sidered as separative. But as soon as we reflect that the Energy recjuired for the purpose is entirely rela- rHE SATURE OF MOTIOX 79 five to the rosistanoes which must he overcome as soon as we recollect that if there were no friction, the initial Enerfjy would carry on the movin«T body for ever, and that where there is little friction the moving body contiimes to proceed for a long period in the same direction without conspicuous loss of speed— we see that each new increment of energy from the l)urning coal is used up— not in intensify- ing the rate of motion, but in overcoming friction, in wearing down the projecting particles of the machinery and the rails, in producing heat, and so, ultimately, in setting up separative actions. This case leads us on to that of a planet having orbital Energy, or a molecule having Vibratory Motion. In both these instances the substance to which the Enercry is imparted is far subtler and more tenuous, being in fact the ethereal medium. Yet in both we see that as their Energy is lost, they aggregate with attractive bodies, and we thus perceive the separative nature of their motion. At the same time we see it as a mere incident in the transference of separation from matter to ether. Lastly, in the case of aggregative move- ments, we see that the Motion replaces for a time the separation of masses, molecules, atoms, or electrical units, as they rush together; but we also see the same separation afterwards transmitted to some other form of matter or to the ether, as heat, li^dit, elec- 8o ABSTRACT OR AXAIA'T/C trical separation, or some other form of separative Energy. Again, in every ease, the ether is the final gainer of Energy, and every Motion is only an incident whirh ultimately effects the transferof Energy (i.e. separation) from matter to ether. On the surface of our earth, where so large an amount of Energ}- is being daily poured down by the sun, this truth is masked by the fact that new Energy continually replaces tlie old. Ihit if we leave out of considerati(Mi the accretions thus made to our store of Energy, we shall see that every Motion originates in an aggregation — whetner it be through the fiill of a body at a heiglii, or the burning of coul in an engine, or the oxidation of food in an animal body — and that after the motion has taken place, there is a less total of Potential Energy on the earth, while the Kinetic Energy has been trans- ferred, in whole or in part, to the ether. This prin- ciple, here briefly alluded to in the abstract, will be fully developed in the portion of this work devoted to concrete phenomena. Far more evident, how- ever, is this truth when we look to the wider sidereal system. There, we see at once that all Kinetic Energy is the correlative of an aggregation, and that the separative Power, which once divided the ponderable matter composing the various suns, is now being radiated off, as they aggregate, in the form of ethereal Kinetic Enertiv — or, as we oftener say. of Tiight aiul THE .\ATUKl-: OF AfOTWX Si Heat. This Eiior^ry, when it falls i.p„„ smh a mass as our own planet, at once displays its separative nature by such phenomena as the melting of ice, the raising of aciiieous vapour, the formation of wincls,'an(l the production of living organisms. These questions, again, will be fully discussed in the Second Tart of til is book. Briefly, we may say that the shortest formula to embrace the facts of Kinetic Energy is the follow- ing:— Motion is the redistribution of separations. We have now completed our rapid survey of the abstract principles of Transcendental Dynamics, and may proceed to consider their concrete numifesta- tions. JJefore doing so, it was the author's origiual intention to glance briefly in a separate Part at certain . othersu])()rdinatefactsconnectedwiththedevelopment of the subject. The Laws laid down in the present First Part mostly refer to that department of science known as Physics; though we ha^'e treated incidentally of many facts commonly h.oked upon as chemical and electrical. A special Part ought f(» have been dedi- cated to a brief examiuation of certain ([ualitative propositions in Chemistry and Ele(;trical Science : but this task, unfortunately, the author has found impos- .sible of achievement with his existing knowledge. He therefore proceeds at onre to the ronerete mani- fest at i(ms. .4 ^' k' Tart IT. CONCRETE OR SYNTlfETfC S CHAPTER I. DYNAMICAL FOHMULA OF THE UXIVEHSE. We have now to consider in their concrete appli- cations the abstract hiws laid down in the First Part. Our chief object in doing so will be to show how simply and clearly the wider dynamical relations of the Universe can be comprehended under our con- ception of Force and Energy, as two mutually op- posing and indestructible forms of Power. If we conceive a Universe without any inherent Force, all of whose atoms stood at varying distances from one another, we can see that it would con- tinue for ever motionless, all its Energy remaining in the Potential Mode as simple statical separation.'' ' In the current lanf»imge of Physics, Biich a state of separation would not be spoken of as Potential Energj' at all. It would only be considered as such when a Force attracting the atoms had been intro- duced into the closed system. It is unfortunate that we must use the term * Potential ' in such a case ; but as we have here kept it through- out, instead of the simpler and more logical plirase ' Energj* of Statical Separation ' proiwsed in an earlier page of this treatise, it will be better, in spite of the verbal incongruity, till to continue its use in this Purl 16 coxcKiriK OK sYwrnirnc There would he notliiiij^ to dnivv to^'et her its scat- tered parts, or to set up motion in a sin^de one of its particles. On the other hand, if we con<'elve a Universe actuated only by Force, we can see that it would a;/«;re«,Mte inuiiediately it' it were in a discrete form, or that it would preserve its inertia if it were already absolutely aggregated. There would be no Conservation of Energy, and each mass, as it glided into the central whole, would simply subside without communicating its motion or sei)aratioii to adjijining masses. liut the only Universe which we know by observation is actuated both by Force and Energy. It consists in part of ponderable atoms, molecules, and masses, each of which tends to aggregate with the others, but each of which can oidy get rid of itt se])aration by jjassing it on to some other substance, either as separation or as its ecpiivalent, motion. It also consists in part of other relatively im})onderable particles, known as ether, occnipying all the inter- spaces, great or small, between the ponderable bodies, and capable of receiving and imparting F^nergy from or to the ponderable units. And inasmuch as ail moving bodies part with some portion of their motion to every other body with which they come in contact Of course the word ' Enerjjy ' itself ill describes sucli a Power as that which we have envisaged under that name— a power wliose chief priniordial manifestation is wholly statical. But we have thought it well to continue calling it by the most familiar name. DVSAMICAL FORMULA OF THE UMVEHSL 87 in every direction, und, fiirtlier, injusnnicli as the interspaces of pondcral)!^ ])odie.s are infinitely j^'reater than the space occnpicd by .snch bodies, it must necessarily follow that the total aniouiit of energy re- ceived by the ether from all ponderable bodies must be very much greater than the total amount of Energy received by all jionderalile boibes from the ether. In other words, the ponderable bodies must be aggregating, and passing on their Energy to the ether. Our Dynamical Formuhi of the existing Universe, so far as it is known to us in its present stage, will therefore be a deduction from the IjJIW of the Indestructibility of Tower — that is, from the joint principles of Persistence of Force and Conservation of Energy. It may be stated as follows. All the ponderable bodies of the Universe are continuously aggregating under the influence of Forces, and are imparting their Energy to the ethe- real medium : such continuous aggregation being only locally interfered with where the Energy imparted to the ether by one aggregating mass falls upon the surlace of another mass, and there sets up temporary separative action, in opposition to the local Forces. It may be added that such local separatlv^e action, as hinted above, is not sullicient in amount to counter- 88 COXC/^KT/-: OR sy\TH/:J7C act the general aggregative action jmkI that, in con- setiueiice, tlie ponderable matter of tlie Universe is daily becoming, as u Avhole, more aggregated, ^vhile the etliereal medium is dailvbecominj? more enertretic : though we have no means oi" knowing whether the Energy absor])edby the ether continues always in the Kinetic Mode, or finally assumes the form oi" statical separation. We have now to apply this Formula to the explana- tion of the concrete phenomena presented by the Universe in its various portions. Our explanation will serve a double purpose, as a deductive aililiation of the several sciences on the Law of the Indestructi- bility of Power, and as a verification of our abstract principles by their exact coincidence with well-known facts. 89 CirAlTEK II. TJIK SIDKRKAL SV.STKM. TiiK lile-hi.story of the material Universe, as known and predictable by us, is the history of its passage from a diffused nebulous state to an an<rreoated solid state, through a vast number of intermediate stages each one of which is an advance in aggregation upon the stage which preceded it. Whether or not the universe had any previous state to that of the earliest known nebula, whether it will have any later state than that of the absolutely aggregated mas;:, are speculative questions into which we will not enter in the present treatise. It will be suflicient for our purpose to trace the history of matter in its existing phase, from its iirst known form as numberless dif- fused atoms, to its last knowable form as a single aggregated mass. All modern science compels us to posit as start- ing point a primordial state of the Universe in which its ■ aious masses, molecules, and atoms stood apart 90 CONCRETE OR SYXTHETIC fioin one another at nnknown distances. ]kit caoli particle liad inherent in it those forces which were destined in the future to effect its aggregation with every other. Accordingly, however we figure to ourselves the beginning as absolute or relative (and it must be allowed that we have here reached the utmost limits of our conceptive faculty), we cannot but suppose that from the moment of that begiiming the various particles began to set at once towards one another. The primordial form of Energy was therefore all Potential, and it nuist immediately have begun to assume in part the Kinetic Mode. If we assume that the primitive cosmical nebula was perfectly spherical in shape, and absolutely homogeneous and uniform in the disposition of its various atoms, then we can hardly resist the inference that, as each particle would be quite eveidy attracted towards the connnon centre of gravity, thej-e would have resulted a single aggregating sphere, whose Potential Energy would all have passed into the form of heat as the atoms clashed together, and would have been slowly communicated to the circumambient ether, until the whole mass had assumed its most aggregated shape. But as we do not find this condi- tion fulfilled by the existing Universe, we must con- jecture that the primitive nebula was not uniform in shape or in texture — that it enclosed within it groups THE SIDEREAL SYSTEM 91 of tenuous nuitter more or less separated iVom other ^r()ui)s l)v lines of demarcation Jiiore or less stron<r. Such ineciualities of distribution may have been in- finitesimal ; for it is only necessary to our purj^ise that certain atoms, besides their general gravitation towards the comuion centre, should also have dis- l)layed a special gravitation towards special centres. Granted this, the reason for the discrete condition of the sidereal masses becomes obvious. But when each ultimate particle began to unite with each other particle, the Law of Conservation de- manded that their Energy of statical separation should not die out as they coalesced, but should pass on to some other body or assume some other form. The manner in which it actually shows itself is that of heat. Within each sidereal mass, the atoms are in a fierce state of vibratory movement, the correlative of their previous separation and of the Kinetic Energy of their mutually aggregative motion. This vibratory movement is perpetually being communicated to the adjacent ether as Eadiant Energy, and a correspond- ing aggregation within the sidereal mass is perpetually taking place. Each sun is thus a body of aggre- gating atoms, being drawn together from moment to moment by their inherent Forces, wlule their Energy of statical separation, after passing hito the continuous Kinetic form as true Heat (molecular vibration), is 92 COXCRETE OR SYXTHETIC yielded up, little by little, to the adjacent particles of ether as Itadiant Eneiyy. The l-jier^ry thus absoi-bed by the ether is passed on by it from particle to l)article of its substance, radiating in every direction tliroughout all space, {^onie small portion strikes the surface of our planet, both from our own sun and otliers like it ; and it is known to us as Liidit o and Heat. We thus see that all the Energy of Light and Heat radiating througli the whole of space from the various material masses has for its origin the statical separation of the primordial neljula. ]kit is this ecpially true of the Kinetic Energy of their various relative motions? There is reason to think that it is. The Universe as a whole has a connnon centre of gravity, towards which all its various masses are attracted. Those masses still possess Potential Energy in virtue of their separation from one another and from this central point of union : and it is clear that if they were to aggregate suddenly round that point, their Potential I^iergy would become Kinetic as they fell, and would be transmuted into Heat as they clashed together at the common cosmical meet- ing-place. It would then be radiated off into the ether, and the matter would gradually assume a solid and perfectly aggregated form. Now, it is possible THE SIDEREAL SYSTEM 93 that some of the sidereal masses mav be thus crravl- tating towards tlie common centre in a direct hue ; and if they are, tlien it is clear that their motion is the correlative of their previous separation. J3iit i^ is more probable that the various suns are pre- vented from aggregating directly with one another by some form of continuous motion. We are sure in the case of the best-known large masses— the earth and other planets— that tliey are prevented from aggregating with their relative centre, the sun, by the continuous Energy of their orbital motion. We also know that certain special suns — the double stars — have such a relative motion with regard to one another. We further know tliat all stars have a proper motion whose cycle is so immense that it cannot be measured by the short period of human observation. It is prol)al)le, therefore, that the ascertained cause whicli prevents central aggrerration in the known cases (namely, orbital motion) mav be fairly extended to the unknown cases. We may conclude, accordingly, that all the heavenly bodies are prevented from aggregating around the common cosmical centre of gravity owing to their possession of a relative orbital movement. Of course, there may be many cycles of such orbital movciiicnts one with- in the other, as we know to Ik- tlie case with the satellites which circle round a jjlanet, while the plane 94 COXCKET/C OA' SYXri/llTlC circles round the sun, and llic sun lias his own proper motion. All that is contended here is nierelv this — that each mass or set of masses is prohahly pre- vented from ai;<;re<'atin<' with each other mass or set of masses, around their relative centre, or around the absolute cosmical centre, by some continuous Kinetic Eneryv, analoijous to the known orbital motion of the planets and their satellites. Now, is this continuous Energy the transmuted form of pre- vious separation in the parts of each mass ? In the best-known case — that of the masses composing the solar system — astronomical authority has decided that it is. Laplace has shown that the orbital motions of the planets and satellites, as well as the axial motions of the sun and its dependent bodies, may be accounted for by the falling together of nebu- lous matter, whose Energy of separation, becoming Kinetic in the act of aggregation, and then receivin<j a check, communicates motion to the whole mass. In what way this axial motion is converted into orbital motion we shall see when we come to(;onsider the solar system in the next chapter. For the pre- sent it must sufllce to point out that the Enei-gy of relative motion in heavenly bodies is thus probably due, like their Energy of Heat, to the primordial Potential Energy of their originally sej^arate and discrete particles. THE SIDEREAL SYSTEM 95 Aj^'iiin, is tliis Molar Kiiicfic Kiiciyy <»r relative motion in the various lioavcnlv bodies Ijcincr yielded lip to the ether, as we fsaw to be the case with their Molecular Kinetic Ener<rj% which is l)eiiig dispersed from moment to moment throu<,di all space in the radiant form ? There are reasons for thinkinf; tliat this also is the fact. It is now pretty generally admitted that orbital Energy is slowly lost by ethereal friction in the case of the planets: and there is no reason to doubt that it is ecpially h)st in the case of these larger masses, the fixed stars. And as the Kinetic Energy of orbital motion seems to be the only barrier to aggregation under the influence of gravitation, it will follow that as this Energy is im- parted to the ether, the various heaveidy bodies will draw closer and closer together, until, when all their Energy has been transferred to ether, they will aggregate in absolute contact around their common centre. Let us restate then, in a simpler way, the proba- l)le con(,'lusions to which we are led. The Material Universe originally existed as avast nebula of discrete particles, in which Persistent Forces and Conservative Energies were inherent. As its Forces drew together the particles into several masses their Potential Energy became Kinetic. Part of it assumed the Molar form, and drove the various masses in orbit 96 co.\'cki:tk or svyniiync within orbit aroiiiid their rchitive centres, and, ulti- mately, round the coninioi coi^niical centre. Part of it assumed the Molecular form, and kept the mole- cules of each mass in a state of rapid continuous vibration. But each Kinetic Energy alike was and is continually being yielded up to the ethereal medium. As Jladiaut Energy, the Molecular motion is from day to day in\parted to the ether, and transmitted to the furthest ends of space. Some small portion of it falls upon other material masses, scattered like lonely islands in the ocean of ether, and may there set up separative action : but the vastly greater portion is never again expended on a particle of matter. As ethereal friction, tlte Molar motion is more slowly vielded up to the ether, in which it produces (pro- bably) wavT^s of heat(or low-powered radiant Energy). And there is no reason to doubt that this process will go on indcfuiitoly until it reaches its final result. The Molecular ]V[otion will probably be dissipated until each mass has grown cold and inert : the Molar Mo- tion will probably be dissipated until all the masses a<jf<n-e<(ate round their common centre. The Material Universe, which began as a number of discrete par- ticles, will end as a single aggregated mass : all the Energy which was inherent in its separate form will have been transferred to the ether : and inotion will have l)cen the means of transference, the repre- THE SID ERE A I. SYSTEM 97 sontative of the sepanitioii during its iiitcnnodJate sta/ie. Of courso, in tliis brief .sketcli of tlie cosmioal lifo- liistory many incidents of vast relative importance are necessarily omitted. One mass — wlietlier sun,])lanet, or satellite, — circlinfj round another, may part with its Molar or orbital Ener;^'y, and may a<:i,n-e;,'ate witli its central mass, lo!i<^ l)efore other masses have d(^ne so. At the moment when two such bodies a^'^fregate, doul)tless some portion of their Molar I'lner^^fy will still remain, and this will probably be converted into the Molecular species, and radiated away as heat and liijrht. But such minor incidents, forminj; the several steps of the great process by which matter is aggre- gated and Energy dissipated into ether, do not inter- fere with the main process as laid down above. Moreover, as the history of one such episode — that of the solar system — will be more fully considered in our next chapter, it is less necessary to enter into details at the present stage. This chapter contains much that is purely specu- lative and may raise objections in many minds. That is inevitable, considering the vastness of the subject and our ignorance of the facts. But as we progress to the solar system the speculative cliaracter of our explanations will gradually decrease : and when we reach our own planet — the most practically important u 9l COXCKICTK OK SYXTHKTIC f to ourselves — the element of liypothesiswill (lisappc.-ir altofjetlier. Forsyininefry's sake, however, it is neees- Bary that the less eertain eosmieal applicntioii of our l)rinciples should precede the more certain mundane application. 90 C'lrArTKPv TIT. Tin-] SOLAR SYSTKNf. Amono tlic minor amrroaatinrr massos into which tlm msmiral noht.la may l)o supposed to have split up, in tlio course of its ^roneral amnv^r.ative cycle, was a prroup of matter out of wliich our own sohir system has ])een developed. In its earliest separate pliase we may sui)pose tliis *rronp to have consisted of various minor portions, in varying stages of aggregation, re- volving in a single direction around their conunon contre. (T)etails about the direction of Xeptune and Tranus may he safely neglected.) We mav further Huppose that the nel.uh.us or quasi-nel,uh.us mass thus C(miposed again divided itself, along its weakest rohesive lines, into other portions, which have aggre- gated into the existing planetary gi-onps; while U^ese latter again su})divided themselves into the centi-al masses and their satellites. It is immaterial for our purpose whether, with the earlier evolutionists, we regard these changes as taking place in a relatively u J too COXCRF.TE OR SVWniKTJC liomor»onooussul>st;iTi('o, a (lifTiiscd n('l)iila,or wlictluT, with thoir lator followers, wo sot thorn down to a*'- ^rof,'ativo aotion in coniparativoly solid and discrete masses (meteors), like those which we know to exist in large tracts within the sphere of the solar system. Ihit the inij)ortant point to not ice in either case is this, that these pronpin^'s and su])-<rron})inps took })lace under the inHuence of Forces, and that the Potential Energy of separation between the masses or molecules became Kinetic as they clashed together, and assumed the form of Heat. The various masses thus became each of them a little sun, ajrjjrefjating around their several centres, and radiating their Energy into the surrounding ether. As in other cases, some small portion of this Energy would fall upon neighbouring masses, belonging either to the same system or to other systems, and would there do a little towards retarding the aggregation of their matter and the dissipation of their Energy ; ])ut the greater portion would doubtless be lost in the vast interstellar spaces ; so that the gene- ral result would be a loss of Energy to matter, and a gain of Energy to the ethereal medium. The various planets and satellites thus formed would still possess Potential Energy in virtue of their continued separation from one another. They would also possess Molar Kinetic Energy in virtue of their orbital movement, which acts as a preventive to their 71IE SOLAR HYHTEM loi immediate a^'«,Me^'.ilioii with their common centre, the sun. And, finally, they woiild possess ^^ole('nlar Kinetie Energy through the vibratory movement ot* their molecules, derived from the previous Kinetic Energy of their aggregative motion. But as tlieir particles vibrated, they would j)art from moment to moment with portions of their Energy to the surrounding ether. This loss of Energy would only largely allect the periphery of each mass, and would at first be inconspicuous at the centre. It would also affect the smaller masses much more rapidly than the greater, for two reasons ; both because the amount of aggregatin<' matter being less, the amount of heat generated would also be less; and bt cause losses of heat from the periphery could not so easily be made up by condu('tit)n from the centre. The smaller masses would accordingly cool at their surfaces at comparatively early periods ; while the larger ones, in proportion to the amount of unaggregated matter within the sphere of their attraction, would continue for long periods to receive fresh accessions to their molecular Energy, and to radiate Light and Heat mto the surrounding ether. Especially would the largest mass of all, the central sun, continue for an immense era to aggregate the surrounding masses and to radiate the liberated Energy mto '.ne space around. I02 Cr CONCRETE OR SYXIJIETIC Furtlicr, we may concliitle tlmt as the surface of each mass parted with its Energy, its superficial molecules would be drawn toj^ether bv the Forces of cohesion and chemical affuiitv. We should thus ffet a solid cohering framework on the exterior of each ■ mass, as soon as it had i)arted with a considerable portion of its molecular Ener<iv to the surroundiiij'' ether. ^ Through this cohering crust, the central Energy would slowly escape by conduction: until, sooner or later, we might expect each such mass to consist of a cold and inert collection of molecules, the whole Energy of whose previous separation had been yielded up to the ether. ]3ut a special inci- dent of this transference mijiht occasionally occur to break the monotony of its simjile course. As the central Energy escaped through the cohering crust, there miji'ht be a tendency for the interior molecules to be drawn together under the influence of cohesion and gravitation. A second crust would thus tend to form itself beneath the outer one. Thereupon, the Force of gravitation might outweigh the cohesion of the outer crust, which would yield under the strain and fall in upon the subjacent mass, breaking along its line of least cohesion. Each such ftdl would be ' The cases of the ocean and the atinospherc, whicli ajipcar to contradict this general stati'nient, but whose form is reall.\ due to the poparative action of radiant solor J'^ncrgy, will be treated in the next chapter. THE SOLAR SYSTEM 103 Itself a change of Potential into aggregative molar Kinetic Energy, as the masses fell together ; and ■when they clashed, tlie Euei'uv would assume the molecular form and ])e given oil' as heat. Ihit, how- ever the aggregation takes place, as the matter of each group aggregated more and moi'e closely round its centre, the Energy of its previous separation would he given off as heat, and would fnially be imparted, as in every other case, to the ethereal medium. While each mass was thus parting (l)y radiation) with the Molecular Kinetic Ener»iv result inj"- from its previous separation and aggregative motion, it would also be parting, though more slowly (by ethereal friction) with the Molar Kinetic Energy of its orbital motion. Each satellite would thus be drawing pro- gressively nearer to its primary, and each planet to the sun. As every unit of Energy was lost, gravita- tion would draw the body one unit nearer to its relative centre. It might thus be e^xpected that each satellite would agurenate with its primarv before the primary jjlanet aggregated with the sun. At each such aggregation, though the greater part of the orbital Energy would doubtless be already dissipated, yet it is probable that as the two bodies glided to- gether (for they would not /'c^//, as is often erroneously said) there would be a considerable residue of Energy still reivuiininu', which, on the shock of collision. I04 CONCRETE OK SYNTHETIC would be converted into molecular motion (or heat), and wonld be sutricient to reduce the bodies to a molten state. But this incident, instead of interfer- ing with the final agj^n'cgative ])rocess, would really hasten it : because the new nnited body would at once begin radiating off its heat into space, and once more cool down to a mass of cold and inert molecules. In other words, all the remaining Energy of sejjara- tion belonguig to the sateUite in virtue of its discrete condition, and all the remaining Kinetic Energy of its orbital motion, would thereupon be dissipated into the surrounding ether : and the united mass would continue to gravitate slowly towards the central sun. What is thus probable of the satellites in relation to their primai'ies is equally probable of the planets in relation to the sun. As their Energy of orbital motion is dissipated by ethereal friction, we conclude that they are drawing nearer and nearer, step by st€^p, to the centre of our system. And there is no reason to doubt that they will continue to do so until they each slowly aggre<.jate with the central mass, converting their remaining Energy as they clash together, into heat, which will itself go for a time to swell the volume of solar Energy, and will be radiated off like the rest into surrounding space. Finally, when the sun has aggregated with himself ail the matter of the solar svstem, we mav conclude THE SOLAR SYSTEM 105 that he will ultinuitely radiate off all the iiiolecuilar Energy derived iVoiu their aggregati(Mi, and become himself a cold and inert mass, like some of those biirnt-ont stars revealed to us by astronomy. And then we may imagine that this single sphere, which contains all tlie matter of our system, will itself i)ro- ceed to aggregate with some other mass, in that general cosmical group of wliich it forms an un- important mend)er. Of course, it is impossible to conjecture which of these aggregations will take place first ; and it is quite conceivable that the whole solar system might clasli with some other group of worlds before its various meml)ers had time to aj?<n-e- gate in this regular order with one another ; but if our suggested theory of a general subordination of systems and cycles to a conunon cosmical centre be correct, then just as each satellite w^ould aggregate with its primary before that primary had time to aggregate with the sun, so each planet would have aggregated with the sun before the sun had time to aggregate with its superior mass. However this may be, it will be sufficient if we regard the probable course of events in the solar system as a specimen of the probable incidents everywhere ac- companying the course of aggregation round tlie common cosmical centre, and briefly hinted in the preceding chapter. io6 COXCKETE OK SYXTIIETIC At tlio present inoineut of time, we occupy a middle point in tlie systemic epoch tliiis sketched out. The sun, our central mass, is still in a state of rapid molecular motitni, which he imparts as Kadiant Ener<jv to the ether. He has yet much outlvin<{ matter to ajrgregate, and it seems prohahle that small agcrregations are from day to day taking place. Of the planets, the smaller have cooled down sulliciently to possess a firm and coherent outer crust, while the larger are still in a very volcanic state. The satellites have probably radiated away all their proi)er heat, and are already cold and inert to their centres. The surface of the most easily observed, our own moon, shows the vast corrugations which result from the continual collapses of the crust uj)on the once heated nucleus, and the reactions of the molten interior upon the coherent outer shell : — corrugations relatively (if not absolutely ?) much greater than any at present found upon the surffice of our own earth. Some small fraction of the Energy radiated from the sun falls upon the cooled exteriors both of planets and satellites. Of this, the greater i)ortion is reflected back by dispersion, as we see from the case of the moon, in every direction (only a small fraction of this fraction again falling upon other masses). But a certain lesser portion is used up in heating the outer crusts, ui setting up evaporation, currents, and winds. THE SOLAR SYSTEM ,07 and ill producing tlie iilieiioiiieiia of ori^^auic life. These secoiidaiy s('i)arative reactions of radiattd Ijiei-gy upon tlie surface of a planet foi-ni tlie gi-eat mass of those plienonieiia which arc generally obserxt d by human beings. io8 COACRETE OR SYArHETIC CHAPTEK IV. THE EAIITII. As we pass from the solar system to our own planet, we leave tlie region of hypothesis, and arrive at that of known facts. The earth is a collection of material particles, the vast majority of which, so far as revealed to our observation, are in a state of stable aggregation with one another, molar, molecular, chemical, and electrical. Its centre may be — and probably is — still occupied by a molten (though rigid) mass, whose heat has not yet been fully conducted away : but the outer crust, except at its exposed surface, consists of matter aggregated in those molecularly cohering and chemi- cally passive masses known as rocks. Its exterior is not absolutely regular, but is in places corrugated into certain elevations and depressions which we call mountains, tablelands, valleys, and ocean-beds. The portions elevated above the general level possess Potential Enerrjv in virtue of their elevation : but the THE EARTH 109 Force of gravitation Ix'ing interfered with hy that of coliesion, this ]'iner<ry cannot assume tlie Kinetic ]\[o(le witliout the intervention of an external Liberat- ing Energy. In short, while the centre of the earth may still possess some molecular Energy of its own, which is only slowly esca])ing through the outer crust, its hard exterior is for the most part thoroughly arrrrrerrated and almost devoid of relative Kinetic Energy, except so far as it obtains small daily incre- ments from the solar radiation. If for a moment we leave out of consideration the solar Energy thus absorbed, we can form some con- ception of the appearance which the earth would possess, supposing it left to its own resources. The whole ocean and all the other water on the earth would be frozen into a solid mass. There would be no plants or animals on the surface, nor any winds, storms, rain, snow, or lightning. What might be the condition of the atmosphere we cannot say ; but we may guess that it would be greatly diminished in size, if not absolutely reduced to a solid form. Motion upon the surface would be all but unknown : the only movements whicli could ever cccur being those which would occasionally result from those internal causes that give rise to eartliquakes and volcanic eruptions. These would still take place, as the gradual loss of Energy from the central mass would no coxc/iiyn-: oa' svxti/ht/c make the Force of <fravit;»ti<)n outwci'fli that of co- lu'sion ; and tlie Potential Kner*^'}' vvliicli tliereiH)on would be niol)ili.scd nii;ilit art as a liherative agent to certain masses on the slopes, besides cansinfj perhaps a temporary melting of some small portion o*' the solidified water through volcanic, heat. ]hit these incidents would themselves only accelerate the loss of the remaining pi'oper Energy of our planet, which would soon be imparted to the ethereal medium, and leave our earth at last a perfectly inert mass of aggregated particles. In the world as we know it, however, very dif- ferent phenomena arc observable ; and all these are due to the separative action of Energies radiated from the sun, which fall upon our earth, acting partly as separative agents for the superficial molecules, and partly as liberative agents for the various Potential Energies whose mobilisation is prevented by inter- fering Forces. Falling upon tlie atmosphere, the Kinetic Energy of ethereal undulation prevents its aggregation and keeps it permanently in the gaseous form. If it be objected that the non-absorption of i-adiant heat by the gases of the atmosphere is opposed to this view% it may be answered that actual absorp- tion is not necessarily implied : it will be sufficient for our purpose if the original molecular mobility of the gases is not diminished by conununication with THE EARTH ill the ether. We eaiinot experiment upon the rondnct, of oxy<(eu or nitro^jfcn at tlic absohite zero of tem- perature, ])iit we liave ik^ reason to douht tliat at. some extremely low point they would follow the example of all other bodies, part with their molecular Ener</y to the surrounding^ ctlicr, and ])ass tju'ou^h the lifpiid into the solid form.' We know already that earhonie anhydride can assume the frozen con- dition, and it is hardly probable that the simple atmospheric fj^ii^es would not do the same, under similar circumstances, could we only command suf- ficient Power for their li([uefaction. Fairm<f upon the water, the ethereal Kner<ry acts in opposition to its cohesive Force, and keeps it habitually in the; lif[uid state, at least in tropical and temperate climates. Nor is it only by compelling them to assume the gaseous and li(piid forms that the ethereal Energy displays its separative nature on air and water: it also acts in opposition to gravitation. It heats many water-molecules till they evaporate, ajid then raises them to considerable heights in the air. It expands the atmosphere of the tropics (by conduc- tion and convection), and causes the phenomena of monsoons, winds, and storms. In a similar way it produces the ocean currents. And it thus becomes ' Since this was wiitten, the solidification of oxygen lins been actually accomplished. in coxcRfrri': or sY\Tff/:T/c the cause of all motioiia on the faco of tlio oartli, except those of or<jairK' bcin^^rs, to ha treated here- after. It must be noticed throii^dioiit, liowever, that these disintegrative effects are only directly pro- duced upon the lifjuid and ^^aseous substances in which the force of cohesion is very slight. Those more solid and coherent masses, the rocks, are little acted upon, and that oidy indirectly, by Liberating Energies in the li([uids and gases, as will more fully jippear hereafter. But the Energy which thus falls upon the surface of the earth from day to day, and sets up these sepa- rative actions in its less coherent sujierficial molecules, does not long remain upon the face of our planet. Each portion of the earth's surface is turned (on an averaire) for one half of each twenty-four hours to- wards the sun, and for one half away from the sun. The heat which struck it during the da}- and was partly absorbed by its superficial molecules is more or less radiated away to the ether during the succeed- in<r niijht. In such a case as that of Sahara, where there is no organic life on wliose production the Energy is permanently expended, and little vapour of water to retain the heat — almost all the Energy re- ceived during the daytime is radiated away at ni<dit, so that the thermometer often sinks below the freez- ing point. Here we have the naked facts uncom- THE EARTH iij pliratt'd by tlu* ])r()l)l('ins of life and tlic iiiterfrroiuf of rain and wind. On the ocean, (he solar Knerjjv absorliod by the water raises larj^e masses of waterv vapour to a considora])le lieight. There, the vapour parts sooner or hiter with some of its Kner*ry to the ether, and ajx^ref^atinfj in the form of rain, converts the remainder from the Potential to the Kinetic AFode, finally yieldin_<^ it up again as heat when it once more reaches the ocean. So in this case too, though less conspicuously than in the fornici*, llie absorbed I'^nergy, after causing temporary separations, is before long dissipated, while the particles which it affected once more aggregate in obedience to their inherent Forces. On the ordinary fertile land-patches the solar ]"'nergy is partly returned at once by radiation, as in Sahara; partly used up in evaporation, as on the ocean ; and partly employed in the production of living organisms. In the first case, the retransference of the Energy to the ether is obvious ; in the second case, though less immediate, it yet takes place, as ex- plained above, when the vapour falls again as rain ; but in the third case, the transfers are more invol\-ed, and will have to be treated in separate chapters. It will be enough for the present to point out that every orf^anism sooner or later dies, and that then the Energy which was embodied in its production is once more given up to the ether on the chemical 1 114 coxcki:t/-: on svxT/nrr/c HL'<j;r('j;ati<)n of oxy^'cn niul oilier (Iccomposing aj^cnts ■VNifh its component atoms. Let us now look in detail at a few of the ways in which the separation, yielded up to the ether by ])ar- ticles of solar matter as they a<rj,fre«;ated, is recon- verted into separation between sli^^dilly-coherent mnn- dane particles, and is finally transferred again to ether. A lake in the northernmost part of the temperate zone is frozen over during the winter. The conjpa- ratively small amount of solar Energy wJiich affects it does not suffice to separate its particles from their cohesive union. Ihit when the earth sliifts its posi- tion by oscillating slightly on a particular axis, the conditions of aerial refraction are altered, and the amount of radiant Eiierfxv which is concentrated on this particular spot is largely increased. The first eflfect of this Energy is to loosen the aggregated mole- cules from their solid state and to make them assume the liquid form. The Energy thus absorbed remains in the water as ' latent heat,' in other words either as Potential Energy of separation or as Kinetic Energy of motion : and when the water again freezes, it is yielded up to the surrounding atmosphere, often in the visible form of warm mist. After tlie separa- tive Power has "produced this first effect in melting the ice, fresh quantities are from day to day poured upon the surface of tlie now liquid lake. Here, the THF. EARTH ii; licat prodiu'OH fiiitlicr srpjiiation ln'twci'ii llic supcr- fi(.'ial inolcciilcs, so (liat oven tlio .sli^'lit (■iilicsivc power of liquids is ovorcomo, and tlw particlos assuinc the vaporous state. Tlicrrupoti llicy aro raisod into flic air, and drifted about hy the winds, which themselves result from the 8e})arative action of heat. After a time, the particles lose by radiation and convection much of their Kinetic Kner«fy, and l)e<.'in once more to ajrgrpiTjtte into rain-drops. These fall upon the sur- roundin*^ hei<:fhts, and finally find their way aj/ain into the lake. Hut the Ener«.fy which raised them has by this time been di.ssipated, and fresh Enerjiy will be re- quired to make them once more assume the form of vapour. Nor is this all. As the drops fall upon the mountain side, they employ part of their Eiu'r^y in overcomin<^ the cohesion of its molecules. In this way they slowly wear away the elevations on the earth's surface, and carry down their particles to the valleys or the sea. In so doin<.^ they act as liberatinjjf agents for the Potential Ener;iy of these masses, and so assist in working out the general plan of aggrega- tion. It is true that new mountains are from time to time slowly upheaved in place of the old ones, but these are themselves mere a])parent exceptions, as- they really represent a general lapse of the surround* injj crust : and their lieiixhts are in turn worn down by watercourses, glaciers, and percolation. In short, J 2 ii6 COXCNK/r. Oh' SY.\THI-:riC the soljir Eiicrjrj'- ox])t-iul('(l in ev.-iponition is ulti- mately employed as a liberating agency for the Po- tential Energy of separation possessed by such masses as are raised above the general gravitative sea level of our planet. These masses, though tlieir cohesion is for a while destroyed, aggregate in the end as new sedimentary deposits ; and so the whole process be- comes merely one more step in the gradual aggre- gation of matter and dissipation of Energy to the ether. Winds and : orms act in similar ways. They all arise from some kind of separation, produced in air or water by heat ; or from the subsecpient cooling of the heated masses. In the first case, we see the ab- sorption of separative PoM'er ; in tlie second case the re-establishment of ecpiilibrium on its disengagement. They, too, act as Liberating Energies for the Potential Energy of masses elevated above the general gravita- tive level, as when tliey blow down trees, walls, or stones, and beat the waves against a cliff. In one wav or another, every Energy which falls upon our earth from the sun is cmijloved in weai'in<r down all in- e(pialities of surface,- -that is, in liberating masses possessed of Potentiid Enei-gy, and permitting them to obev tlieir gravitative inn)ulses. The special case of lightning demands a brief ex- planation. Throughout, we have dealt lightly with THE EARTH 11? electrical plienomena, and we must do so here once more. The Potential Energy of the separative electri- cities in the thunder-cloud and the earth is in some way a product of solar Energy. So long as they remain apart, there is some kind of statical separation between unknown units generally aggregated. At last, some Liberating Energy in the shape of wind or heat brings the charwd masses within ranye of their mutual afii- nities. At once a discharge takes place, and the Po- tential Energy is liberated as Light, Heat, and Sound ; all of which are finally turned loose upon the ether as radiant Energy, to pulse perhaps forever, through the interstellar spaces. The only peculiarity of the case is the conspicuous and instantaneous way in which the Potential Energy is liberated and assumes the Kinetic Mode. So, too, witli many human machines. Organic phenomena will demand careful separate treatment ; and until this has been given we cannot properly un- derstand such a case as that of a steam-engine, where the prime Energy is derived from organic products like coal and wood. lUit certain simpler machines like water-mills and windmills may conveniently be explained at the present stage. The water which falls from clouds on an elevated patch of ground still possesses Potential Energy in virtue of its separation from the general gravilative level, and as the force of lis coxcNJ-rn-: oa' synthetic uravitati(jii is very little interl'tTed witli bv cohesion ill the case of litjiiids, the water is enabled to ibvni into a stream, and run down to the sea. On the wav, nnder ordinary circuinstances, it ])art,s with most of its Potential Enei'f>y by friction, or yields it u]) in fall- iiiii" as heat. Ihit where a considerable iall occurs, it is possible to em])l()y this energy in turning a wheel. The wlieel, being comiected with other wheels and giindstones, gives up the Kinetic Energy thus derived, partly in producing separation, in opposition to cohe- sion, among the molecules of corn, and partly in heat or friction. The heat is of course I'adiatedofl", and the rest of the ]^lnergy remains Potential in the flour. So also with a windmill. Here the Kinetic Energy of wind, itself derived from solar ra\s, is transferred to the vans of the mill, and is finally used up ini)roduc- ing separation in the corn, or in heating the bearings and grindstones. In both cases we see, as usual, an . intermediate employment of Energ}- for the i)uri)ose of separating material particles, but a fmal loss of ener<Tv from matter to the ethereal medium. In all these cases we deal with })henomena essen- tially unconnected with organic life : for although the machines mentioned above are of human construction, yet, when once set in a(;tion, they can go on without human intervention until the loss sustained by fric- tion makes their working impossible. In the next THE EARTH 119 chapter we sliall consider the more hivolved ease of living organisms. Before doing so, however, it will l;e well to sum up the conclusions at which we have arrived regarding the general dynamical phenomena of our planet. The earth is a proximately spherical mass of matter, held together by its own gravitation, and bulging slightly towards its equator, where its axial Energy produces the greatest effect. It revolves round the sun in virtue of its orbital motion, and it possesses Potential Energy by reason of its separate condition. This Potential Energy, however, cannot assume the Kinetic Mode, because the solar gra- vitation is opposed by the orbital Energy of the [)lanet. Though the earth thus possesses two proper molar motions of its own — the axial and the orbital — its Molecular Energy has been radiated away into space from the surface at least, only the interior por- tion being still in a highly heated state. The inter- ference of cohesion in this outer solid shell with the generd gravitation whose Force comes into free play as the internal mass cools and contracts, gives rise to a state of tension, fuially resulting in cracks and corrugations on the surface. If no external Energy intervened, the outer shell would present one uniform cold and probably solid surftice, broken up into ice- dad muunlaius and valle\s. lhi( a fraction of the lao COXCKETE OR sv.\Tui:ric Energy radia'od into space by the aggregating masses of the central snn falls on the outer shell and there interferes with the aggregative i)rocess ])y setting np temporary separative action among the less coherent molecules. It keeps the atmosphere and the ocean in the gajieousand liquid forms respectively. It prodnces such an expansion of the erpuitorial air as gives rise to monsoons ; and elsewhere it heats the atmosphere of deserts, valleys, and low-lying plains so as to cause local winds and storms. It also lifts up great masses of water, which float in the air as clouds, and finally fall as rain when their Energy is dissipated. It heats the equatorial oceans, and thus rendering them lighter sets up warm ocean currents, while gravitation, draw- ing down the colder uiasses, produces the compensat- ing cold streams. The separative nature of all these processes will be obvious when we reflect that evei'v one of them depends upon such an absorption of i-adiant heat as overcomes the aggregative Force of cohesion. But these changes are never permanent. The Energy thus absorbed is soon radiated off to the cooler ether in those less energetic periods which we know as night and winter. Unless everv dav and every summer new Energy w^ere poured upon the earth to set up similar separative actions, the effects of each Energy-absorbing period would soon pass away. The vapour and the water would part with THE EARTH 12 1 llieir heat, condense, and finally I'reeze : Avliile the air ■would cool down, settle into stable equilibrium, and ])erhaps aggregate at last into the solid state. ^More- over, the Energy which thus falls U})on the earth acts indirectly as a liberating agent to those more solid masses which are prevented by cohesion from aggregating in the stablest possible manner with the general body of the plaiiet. By wearing down moun- tain sides ; by water-action, percolation, glacier-grind- ing, and attrition of rolling bodies ; by blowing over stones, chinnieys, and trees ; by wasting cliffs, head- lands, and river-banks ; by grinding down pebbles, shells and refuse ; and by depositing all the debris thus lesulting in new and lower strata of mud and sand — bv all these wavs and countless others, to which every gorge, ravine, denudation valley, and seaward clifl' bears witness, the Energy poured down upon us from the sun acts as a liberating agency to reduce the in- ('({ualities of our planet's surface, and bring eveiy body ultimately into closer and more intinuite aggre- gation with the general mass. Thus we see that on the surface of our earth the universal process of aggregation continues in spite of partial interruptions. Incident Energy let loose from the aggregating sun produces local and temporary separations among its material particles ; but such separations do not interfere in the end with '^2 COXCRETE ON SVXTIIETIC the general aggregating process, mIiIcIi they ratlier indirectly assist. As elsewhere, we find all tlie matter engaged in a continuous course of aggregation, and all the Energy thus liberated continuously handed over to the ethereal medium. >^1 CllArXKli V. OllGAXIC LIFE. TiiK interferences caused by incident solar Energy in the aggregative processes of our earth Avhich were considered in tlie hist chapter niostl}'' consisted in separative actions opposed to tlie niolecuhir Force of cohesion, and, less directly, to the molar Force of gravitation. Those phenomena which we have to consider in tlie present chapter are the result of interferences by solar Energy opposed to the atomic Force of Chemical Aflinity. It is not here asserted that *'/// the cases where solar Energy interferes with and opposes Chemical Affinity are concerned with vital i)henomena. But vital phenomena form the principal instance of such interferences, and all the others may be omitted as illustrating no new principle and suggesting no new difficulty. Ivcfiarded in their naked dvnamical asi)ect these phenomena may be brielly described as fol- 124 COXCKETE OR SYNTHETIC lows. The incident solar Energy, — besides falling upon molecules in the slightly aggregated cohesive states which we know as the liquid and the gaseous, and overcoming their very moderate cohesion so as to produce evaporation and expansion — also falls upon certain atoms aggregated together by the Force of Chemical Affinity, and sets up in them separative actions, which result in the severance of these atoms from their alfinities, and the rebuilding of some among them into those peculiar forms which may be described as Energetic Compounds (hydro-carbons, &c.), while the remainder are cast in a free state upon the atmosphere. The radiant Energy thus employed is used up for the time being in producing these separations, and is retained j^artly by the freed elements, and partly by the Energetic Compounds, either in the Potential Mode or in the Kinetic, or partly in one and partly in the other (for on this ])oint w'e have as yet no certain knowledge). The Energy thus absorbed l)y the Energetic Compounds apparently remains witliin them permanently, until some incident Energy, acting as a liberating agent, causes their atoms once more to unite wntli those other free atoms in the atmosphere for wOiicli they liave affinities. When they reunite, all the Energy which was absorbed in producing their separation is liberated once more by the act of aggregation, ()A'(;.l.\7C l.lll: 125 ;iii(l is yicUU'd up to the ctlier as low-p^rado Energy. Wliile the Energy is retained by tlie freed element and the Energetic Compound we may either suppose that it is all Potential and consists merely in the statical sejjaration of their atoms, — on which sup- position it will be exactly analogous to the case of a rock, raised to a height and then supported so that it cannot fall without the intervention of a liberating Energy : or we may sujjpose that it is partly Potential and partly Kinetic, and consists not only in the sta- tical separation of the atoms, but also in a relative iTiotion of the atoms in the p]nei-getic Compound, — on which supposition it would be analogous to the case where a collection of bodies like the solar system, liaving relative motions of their own, possess Potential Energy with reference to some other external body, like the star in Hercules, towards which the solar f^ystem is sujjposed to be moving. It is clear that on the first supposition tlie amount of Energy lil)erated by the reaggregation of the atoms will be equivalent to the Potential Energy of their statical separation : but on the second supposition the amount liberated will be equivalent to that Potential Energy, p/w.s the Kinetic Energy of the rclatixc motions possessed by the several atortis — just as, if the sun were to aggre- gate with any fixed star after all his j)lanets had already dissipated the Kinetic Energy of their several 126 co.\ck/:tk UK sv.\r///:/7C orbital motions, ami iinilcd witli liis mass, the J^irtov liberated by the agjj^regatioii would l)e the ec|iiivaleiit of the statical separation previously existing between the sun and that star; \vhereas, if the afrgregafion ■were to take place to-day, the amount of Encrgv liberated would l)e equivalent to the statical separa- tion of the two systems, plus the Energy liberated by the stoppage of orbital and axial motion in each of the planets and satellites. It is not improljablc that, in certain instances at least, we niav be induced to accept the second of these two snj)positions. Translated into concrete language, the above abstract propositions may thus be more simply ex- pressed. Solar Energy falls upon a crust contain- ing the molecules of water, carbonic aidiydride, the various nitrates in a state of solution, and other i-aw materials of organic matter. It finds their atoms in a condition of relatively stable chemical combination — in other words, closely bound up with one another by the Force of Chemical Aflinily, ]3eing absorbed by some or all of these atoms, it sets them free from their stable unions, by producing motions which take them beyond the sphere of their mutual attractions. It leaves the oxva'en of the carbonic anhvdride in a free state, while it builds up the carbon with the hydrogen of water into certain Energetic Compounds, such as starches, t^'C. The Encrg\' of these com- ()A\;aa7C uri: la; pounds may be all rotciitial — that is lo say, may consist in the fact of their statical soj)arati()n from the attracting oxygon and tlicir loose chemical apposition ; or it may be partly Kinetic as avcU — that is to sav, mav also consist in the fact that the various atoms have relative movements like those of a planetary system. Furtheiniore, in the case of tlu? Energetic nitrogenous compounds there is reason to suppose that a suppressed Energy is also involved. Once these Energetic Compounds have been built up, they remain permanently inert, retaining their Energy themselves in a dormant state — at least so far as human observation can detect — until some Liberating Energy brings them once more under the influence of Chemical Affinity. Thus a piece of wood or a lump of fat, once produced, remains inert, at least to out- ward appearance, so long as it is kejjt at a low tem- perature and isolated from disintegrating agents. But so soon as we apply a certain degree of heat to either, they burn away ; or, in other words, unite once more with the oxA'<>en from whicli thev were i)re- viously separated, and yield up as they aggregate all the Energy of tlieir separation and their relative movement (if any) in the form of Light and Heat. Moreover, there are several ways in which such a liberating agency can be set in action. It may be by human aid, and the intervention of exteriud I2.S coxcKirn-: ok sv.\T///:nc \my\\\\\\f iniitf«'rs, ns wlicn we liL'lit :i piece of u'ood or aeandhi ])}' incjinsof anmtcli. Or it may l)e In'thein- tervontion of sonic animal orrranism, as when a worm burrows into a piece of wood and uses up its Poten- tial K/iergy in tlie performance of his piiysiological functions, ])y causing its atoms to combine with oxygen witliiii his body: or as wlien a carnivorous animal devours tlu; fat, and so em[)loys it in liis physiological functions : or as wiien the animal which has deposited it, himself employs it for his own use, which case we see illustrated in the bear and other hibernating animals. Or, again, it may be hy the set of external liberating agents which produce what we call decomposition : as when a tree decays slowly where it fell, under the influence of moisture and L'cnlle lieat : or when a dead animal decomj)oses in the suidight : — though these latter cases are sure to be accompanied by the devel()})ment of other organisms, which act as liberating agents, such as fungi, maggots, vibrios, and other like organisms. Hut whatever may be the means bv which is brou<fht about this recombina- tion of the organic substances with the oxygen pre- viously liberated from their affinity by solar Energy, there are two points which can be laid down as certain. First, that no sucli reaggregatir)n of the separated atoms can take place without the interven- tion of a liberatiui; agent, whether that liberatin*' 0/iGAXIC LIFE U9 agent be moisture, solar ligljt and heat, animal ^'erms, t'liiigiia spores, or human interferencre : as we clearly see in the tact that to preserve an or«(anie substance we nuiy either desiccate it, or freeze it, or seclude it from light and heat, or from animal and vegetable germs, or secure it from being devoured by some other organism, or from the interference of human beings, who might burn it or otherwise cause its re- aggregation with oxygen : while on the contrary we know that exposure to one or other of these liberating agents will bring about such reaggregation (or de- composition, as it is oftener though less accurately called) in every kind of organic matter. Second, that on the whole and in the vast majority of cases almost every piece of organic nuitter aggregates at last with the oxygen or other free atoms from which its ele- ments were at fust severed, and yields up its Energy to the ether in some more or less conspicuous mannei'. Thus, sooner or later, every plant, if left to itself, dies and decays : that is, recoml)ines with oxygen slowly, under the influence of moisture, light, and heat, and yields up its Energy by inconspicuous degrees ; while every animal, if left to itself, similarly dies and decays, probably under the influence of other small animal germs, which use up its contained Energies in carry- ing on their own activities : and so, in both these cases, the atoms finally rcaggregate in stable com- K 130 CONCRETE OR SYNTHETIC bination, while the Energy is yielded up, immediately perhaps to surrounding matter, but finally to the ethereal medium. So, too, if the plant or animal is devoured by an animal oiganism, its atoms are made to combine with oxygen within the devouring organism, and their Energy is yielded up as heat and as movement, either of internal parts or of external limbs, and is thus finally dissipated. And even if, as in the case of peat, petroleum, and coal, or of the Siberian mammoths, the Energetic Compounds are long secluded by their circumstances from Liberating Energies, it may j^et finally happen that human activity may intervene to liberate their Energies, as we see ■'.vhen we burn coal, petroleum, or peat, or when we exhume mammoths, and so expose them to the decomposing (liberating) action of the sun and organic germs. So that organic life, when closely considered, proves dynamically to be a mere special case of the general laws : and we see that though it is in its nature separative, as being the product of solar Energy absorbed for a time by particular mundane particles, it nevertheless results in a final reaggregation of atoms in stable combination, and dissipation of Energy to the ethereal medium. A word of explanation is necessary. It may be asked, why will not the organic compounds aggregate at once with the free oxygen, and why do they need ORGANIC LIFE 131 the liberating agency of heat or other Energy ? The answer is probably analogous to that which we gave in the case of cohesion. Unless the atoms are brought very close to one another they cannot api)arently get within the range of their mutual affinities, and mere mechanical juxtaposition is insufficient for this purpose without such atomic vibration as will bring them into close quarters with one another. But the more complex animal compounds, as we shall see hereafter, seem to possess high Kinetic Energy of their own, which can only be kept up in the circum- stances of the body : and it is probable that they spontaneously decompose (or split up into simpler and less Energetic compounds) with a liberation of Energy on any direct contact with external agencies.^ In the present work no attempt will be made to account for the origin and development of living organisms. That task has been satisfactorily per- formed in portions by Darwin, Haeckel, Mlillei-, Huxley, Wallace, Hooker, and others, while a more comprehensive and systematic view of the whole process has been given by Mr. Herbert S})encer (whose name I can never pass by without the expres- sion of my deepest intellet^tual gratitude and venera- tion). Their results can easily be translated into terms of the theory advocated in this work : and they ' About this point tlie author is now extremely donlitfiil. K 2 ^32 COACRKTJC OK SYNTHETIC liave not sufficiently direct dynamical bearings to concern us greatly in our present inquiry.^ It must suffice here to recognise the fact that life owes its origin to the chemically-separative action of ethereal undulations on the cooled surface of the earth, espe- cially carbonic anhydride and water, and that the existing diversity of organic forms is due to the miiuite interaction of dynamical laws. It will, however, be desirable to point out that life is essentially separative in its nature, because the identity of Energy with separation is the main point insisted upon in the present treatise, and life is the Mode of Energy with which human beings are most familiar, and from which they form their conception of all its other modes. Life, then, is shown to be essentially separative, first, because it is a product of solar Energy, acting upon the superficial matter of the earth. This Energy is the locomotive form of the statical separation once existing between the particles of the sun's mass. "When it falls upon the earih, being then in the ethereal form, we know that it is partly absorbed by various loosely aggregated superficial material molecules, in * It must be understood that no disrespect towards such inquiries is intended in the present passage. On the contrary, there can be no doubt that, bea-ring as they do on all our acts and theories as living beings, these questions are of paramount practical importance. But they are not necessary to the present subject, and they have already been treated sufficiently by proper and competent authorities. ORGAMC LIFE 133 wliicli it sets lip separati()i\s that overcome the niole- cuhir Force of cohesion, and so produces winds, storms, ocean currents, clouds, &c. Now it simiUirly falls upon certain other molecules, among whose atoms it sets up separations that overcome the atomic Force of Chemical Affinity, and so produces starch, albuminoids, free oxygen, and other like chemically Energetic bodies. The separative nature of this process is obvious. Without the disjunctive solar Energy there could be no life, just as there could be no wind, ocean currents, rain, or clouds. All the stable chemical compounds would remain for ever in the aggregated state, unless the solar Energy came in to separate them. Again, life is seen to be essentially separative by its mechanical position and effects. Trees, plants, and animals stand out for the most part at a visible elevation from the mass of the earth's solid crust, and when they die, large portions of them fall down and are reaggregated with its sub- stance. The heat which sets up evaporation in leaves causes a capillary circulation in the vessels and cells of the plant, whereby water, holding in solution nitrogenous salts and mineral matters generally, is raised to every part of its surface ; and then a large portion of this water is evaporated, while the mineral matters remain in the leaves and fibres. In all this we obviously see separative action opposed to 134 COXCKETE OR SYNTHETIC gravitation, as above we saw it opposed to chemical affinity. Still more clear is this point of view in animals, which climb trees, plants, rocks, and mountains ; which fly to great heights in the air ; and some of which carry about great masses of bone, while others lift stone and brick to conspicuous ele- vation as houses, towers, and steeples. No one of these separative acts could have been performed without the intervention of solar Energy. But it is especially in its reconversion that organic matter shows its separative nature. As its atoms reaggre- gate, they give out heat, which obviously causes molecular separation in the surrounding bodies. The animal organism is perpetually in such a heated condi- tion, and is perpetually parting with heat which goes off to swell the volume of ethereal Energy. So that in every way life reveals itself as an effect of the separative action exerted by ethereal Energy on the superficial material particles of our planet. Succeeding chapters will deal with the phenomena of vegetal and animal life severally, as enforcing and illustrating these principles. For the present we may content ourselves with a brief summary of the results already attained. Organic life is one of the effects wrought by incident solar Energy on the surface of the earth. It originates mainly in separative actions, whereby ORGANIC LIFE 135 atoms are severed from relatively stable clieinkal combinations, and are either turned loose upon the atmosphere in a free state, or are built up into Ener- getic Compounds. But through the action of libera- ting agents, also of solar origin, these free atoms and Energetic Compounds for the most part sooner or later recorabine ; whereupon the absorbed Energy is once more liberated and turned loose upon the ether. Organic life is thus a transitory result of the general aggregating process during which the Energy libe- rated by the aggregation of particles in one mass falls upon the aggregated surface of another mass, and there sets up separative actions, which, however, are most often only temporary in their effects, owing to the subsequent incidence of Liberating Energies, whereby the absorbed Energy is once more turned loose upon the ether. 136 CDXCK/iTE OR SYXTIIETIC CHAi*Tia( yi. TlIK VEfiKTAL OIUiAXIt?M. Ai.TiiouGii ill tlie last chapter, where we treated of life generally as a pnxluct of incident solar Energy, we made little distinction between tlie two main forms of life, it must yet be understood that the rela- tion which, as wholes, they bear to the incident Energy is exactly contrary. Vegetal organisms, as a rule, are accumulators of Energy, and not expenders : ani- mal organisms, as a rule, are expenders of Energy and not accumulators. In other words, the vegetal organ- ism is a case where incident Kinetic Energy is setting up separative actions between aggregated atoms, aiid is being absorbed (or potentialised) in the separa- tion so produced : while the animal organism is a case in which the atoms so separated are being reaggre- gated, and their Energies, Potential or Suppressed, are assuming the Kinetic Mode, either as heat or as visible motion. The energy absorbed and potential- ised by the plant, is kineticised and given off by the animal. THE VEGETAL ORGAMSM 137 These statements must only be accepted as true ill the gross, and with certain deductions duly noted hereafter. The phuit is the origin of all the Energy i)()ssessed by all living beings. The separation between the atoms of water, carbonic anhydride, and nitrogenous salts, which takes place in its tissues under the influence of sunlight, is the Potential Energy which becomes Kinetic in the growing seed, the expanding flower, and the leaping or flying animal. We may there- fore briefly trace the life-history of a plant, as throw- ing some light upon the dynamical nature of life generally. Every plant starts as a spore or seed, cast ofT from a previously existing plant. This first germ contains some small materials for growth for the young plant in the form of Energetic Compounds, wliose Potential Enercfv is to become Kinetic in the act of germination. In order, however, to produce this effect, liberating agents are needed ; and these libera- ting agents are generally three in number, moisture, lieat, and light. Tliese, acting upon the materials in the seed, either cause them to aggregate with other matters, or overcome the suppressing Force ; and in consequence the materials yield up their Potential or Suppressed Energies in that determinate form im- posed by the specific conditions and known as ger- 138 CONCRETE OR SYNTHETIC iiiiiiation. Tlie amount of Energetic materials supplied to the new plant (or the fresh year's growth) may be very great, as in the potato tuber, the lily bulb, and the wheat grain, or it may be very little, as in fungi, ferns, and cryptogams generally : but in every case, if the plant is to continue living, there must be enough Energy to permit of its assuming the shape in which it can begin to be acted upon by the sunlight, and to assimilate fresh matter under the influence of that incident Energy. This stage is reached when leaves are produced. On the surface of these leaves the solar Energy produces evaporation, and this evapora- tion gives rise to a general capillary action, whereby water is raised into the leaves. In these leaves the sunlight, acting upon carbonic anhydride sucked in from the atmosphere, frees the carbon atoms from their union with the oxygen, and builds them up with the hydrogen into hydrocarbons — Energetic compounds : while the oxygen is turned out upon the atmosphere in a free state. Nitrogenous salts in solution have also been supplied by the water, and from these and the starch, the plant in some un- known way builds up the protoplasm which forms the moving portion of all living organisms. The starch, sugar, albuminoids, and other organic compounds thus produced are then circulated all over the plant, where they supply the materials for growth, and rUE VEGETAL ORGANISM 139 develop new leaves, wliicli in turn increase the amount of Energetic matter in the plant. Tart of the Energy thus absorbed is used up by the plant itself in its own physiological processes. The growth of each cell doubtless involves the expenditure of Energy — that is to say, some Energy previously con- tained by the protoplasm assumes thereupon the Kinetic Mode, and is in part yielded up to the ether. In the larger physiological processes, such as germina- tion or inflorescence, it is certain that such dissipation of Energy takes place, in the first place because free oxygen is absorbed and carbonic anhydride is evolved, which shows that some of the contained carbon has reaggregated with the oxygen ; and in the second place because a rise of temperature can be shown to accompany these processes. Accordingly we may conclude that the motions which take place in plants are due to the reaggregation of certain Energetic particles with the free atoms of their neighbourhood, and that while some of the Energy thereupon liberated has assumed the form of Molar Motion, part of it has been dissipated as heat. But a large portion of the Energy remains dormant in the plant, either in the molar or the atomic species. The leaves and stem as wholes, viewed mechanically, represent the former : the starch, protoplasm, and wood, viewed chemically, re- present the latter. When the plant dies or is devoured. I40 COXCRETE OR SYNTHETIC on the average of iiistatices the greater part of this Energy is rendered Kinetic, and iihiinat el}' yielded up to the ether. Take first the case of a tree which dies a natural deatli. At the end of each year its leaves fall. Before they do so, they render up their most important chemically Energetic products to the permanent portions of the complex organism ; but inasmuch as they will burn, they retain a certain amount of atomic Energy in their cellulose ; and in- asmuch as they are elevated above the general level, they possess Molar Potential Energy in their position. When the leaves drop off by the weakening of cohesion at their bases (along a pre-arranged line) their Molar Potential Energy becomes Kinetic in the act of fall- ing, and is dissipated as they reach the ground. The dead leaves, lying on the earth, now consist mainly of inorganic earthy matter and cellulose. The action of moisture, heat, and light, as liberating agents, soon sets up decomposition : and the mineral matter lies in situ, while the organic substances com- bine with the surrounding oxygen. When the whole tree dies the same process is repeated on a larger scale. The actions of moisture, heat, and light, com- bined with those of fungi, w^orms, &c., are liberating agencies which cause the trunk to decay and fall, and afterwards produce more or less complete decomposi- tion of the whole tree as it lies. In a few cases, THE VEGETAL ORGAMSM 141 which will be treated of hereafter, the stored-iip Energies are long retained in coal, peat, and vegetal debris : but on the average of instances, almost all the Energy absorbed during one year has been yielded up by the next. When the plant is devoured by an animal or burnt by man, it undergoes a somewhat different yet ultimately identical cycle of changes, which will be more fully detailed in our next chai)ter : for the present it will suffice to say that its Energetic Compounds combine with free oxygen within the animal organism, or the fireplace, and that their Energy is used up in the production of motion and heat, and is thus, as usual, finally transferred to the ethereal medium. The special case of reproduction requires a few additional remarks. Where this function is carried on by inflorescence, we have a series of leaves pro- duced which are expenders of Energy, instead of being accumulators, growing and unfolding by the employment of Energy stored up in other parts of the plant. Most esjoecially is this the case with the pollen, ovule, and seed. In the protrusion of the pollen-tubes and the growth of the embryo, we see conspicuous instances of the cmi)loyment and dissipa- tion of previously stored Energy. In the developed seed we sometimes find a store of albumen ; and in any case we have in the em])ryo itself a nitrogenous 143 CONCRETE OR SVNTI/ETIC iiiJiHs whicli is al)le, under the influonce of moist iin^ and heat (hbtTutiufj; aj^'ciits), to ag«^regate in part with oxygen and [)rodu(^e germination. Somewhat similar in their dynamical nature are those morpho- logically unlike propagating portions whidi lay up nutriment for the future growth of the individual or its oflsprlng. Such are tlie roots and tubers of l)otato('S and heets, the tu])ers of the orcliis and dahlia, the corms of tlie saffron, and the bulbs or buroils of the onion and the tiger-lily. In every case, motion in plants is caused Ijy the aggregation of free oxygen with the Energetic Compounds of tlie plant, and by the employment of the Energy thus liberated for the production of Molar motion. It will thus be seen that even those plants which are on the whole ac(;umulators and storers of Energy are themselves to some extent likewise expenders of Energy : and that the broad distinction which we have drawn between the vegetal and the animal organisms, viewed dvnamicallv, must not be pressed too close. In growth, in inflorescence, and in germination, the plant is essentially an animal. It is only in assimilation that it displays the charac- teristic vegetal function of transferring Energy from ether to material particles maiidy by the production of hydrocarbons, plus free oxygen, from carbonic anhydride and water. We may thus say roughly, in 77/A V EG ETA I. ORGAMSM I43 reffTonce to our present staiulpoinl, tl\at the as- siiniljiling leaf, IVoiul, or thallus, is the only true plant. Nor is this all. Afany or^Mni.snis, clas.scd inorpiiolojjjically a8 plants, are in their dynamical aHpect the analo<;ue8 of animals : that is to say, their funetions are wholly expensive of Energy and not at all aceumulative.' The leafless j)arasites (orobanche, cytinus iVc.) fasten iiixm some other j)lant, and without themselves eontributiuj,' to the general store of Energy, employ the Energetic Compounds laid up by their host, in the production of their own flowers and seeds. A much larger and more important class is that of fungi, which live upon the roots, stems, seeds, or tubers of otlier plants, upon the bodies or the dung of animals, or upon the generally difhised undecomposed organic matter of the soil. But whencesoever they derive tlieir nuiterials, they always thrive upon previously-composed Energetic Com- pounds, whose Energy they liberate with almost explosive power. They are like animals in never accunudating Energy, while expending that which has been previously accumulated by other plants. It is noticeable that all these (piasi-aninud functions can be carried on in the absence of light, that is, of high- ' Allusion is not here made to insectivorous species, like Dionira, Nepenthes, and Drosera ; but to plants which derive their whole material from previously orRanised matter. 144 CONCRETE OR SYNTHETIC power radiant Energy. Thus, a seed will germinate, a hyacinth will grow from its bulb and produce blossoms, a potato Avill sprout from its tuber, a flower will open, and a fungus will pass its whole life, under proper conditions of heat and moisture combined with the presence of oxygen, in a perfectly dark cellar : because the Energetic compounds, and the free oxygen whose a<;OTef(ation liberates their Enerjjfv, are all stored up in the plant or its environment beforehand. Jhit no assimilation, no separation of atoms from their sta])le unions, can take place except under the dis- junctive hifluence of radiant Energy. So, in spite of these numerous exceptions — these quasi-animal functions of all plants, and these large groups of ])lants with none but rpuisi-aninuil func- tions — the distinction which we have marked between l)lants and animals is yet of cardinal importance, and for this reason. Though some plants are quasi-animal, no animal is quasi-vegetal.^ All the Energetic Com- pounds which enter into the composition of any living- organism are derived, directly or indirectly, from l)lants. In the leaf or thallus or body of some plant or protophyte all the organised materials have taken their rise, under the separative influence of radiant Energy. ' Exception may be made of a few doubtful chlorophyll-containing animals. THE VEGETAL ORG AX ISM I45 To sum up, the conclusions at which we have arrived are these. Sohir Energy, phiying upon cer- tain superficial material particles of our planet, separates their atoms into Energetic Compounds and free elements. The masses immediatelv built up of these Energetic Compounds, together with certain inorganic (or stably-compounded) substances, are known as plants. The}' go on continuously assisting (by means of their chlorophyll) in the similar separa- tion of other atoms by solar Energy, some of which (liydrocar])ons) swell their mass, while others (oxygen) are turned loose upon the atmosphere. The Energy thus" stored in the matter of the plants and the free elements about them, does not remain perpetually connected with the same particles. Partly it is used up in the physiolo^yical operations of the plant : partly it is stored away in seed, tubers, &c., for future physiological operations : partly it is dissipated at the death of the plant. In a vast number of instances the plant is eaten by an aninial, and in that case the reaggregation of elements and dissipation of Energy takes place within the animal's body. So that, in the majority of instances, the Energy radiated from the sun into the ether, and temporarily employed on the surface of our planet in the production of vegetal life, is sooner or later cast once more upon the ether, to make its way forever through the interstellar spaces. 1. 146 CONCRETE OR SYNTHETIC Only a small portion remains here, dormant in wood, coal, and peat ; and even that small portion, as we shall hereafter see, is finally used up by animals (in- cluding man) for some purpose connected with their vital necessities. J47 CHAPTER VII. THE ANIMAL ORGANISM. In the last chapter we saw roughly what were the dynamical relations of those organisms which act mainly as accumulators of Energy. In the present one we must make a similar investigation regarding the dynamical relations of those organisms which act mainly as expenders or dissipators of Energy. Amongst these, as already noticed, are many themselves of vegetal origin ; and it may simplity matters if we first look briefly at their nature, after- wards noting the principal points of distinction be- tween them and the animal organism proper, A fungus grows upon a decaying tree. It has its origin in a spore ; and this spore, alighting in the neighbourhood of previously-accumulated Energetic Compounds, has its own Energies liberated by heat and moisture; and thereupon becomes in turn a liberator of the Energies in the organised matter around it. These it gathers info its mass, and ora- 148 COXCRETE OJi SY XT J IE TIC dually dissipates, with the exception of that portion which it bequeaths to its spores, thereby once more beginning a similar cycle of changes. Wherever the fungus seats itself, — whether on the root or stem of a plant ; or on a seed, tuber, or other receptacle of Energetic Compounds destined for future growth ; or on an animal body ; or on a patch of soil containing dispersed undecomposed organic matter ; — it adds nothing to the total of Energy, being merely a dis- sipator of the Energy already accumulated. Now, the animal organism is a mechanism in which these same processes take place, but take place muc^h more rapidly and conspicuously, and are accom- panied by certain secondary phenomena. As the highest organisn\s show all the processes of the lower, and also some others peculiar to themselves, it may be convenient to take an example from the upper ranks of animal life to illustrate the specialities of the case. A young vertebrate begins its existence as a small mass of Energetic Compounds presenting elementary organisation, surrounded by another mass (more or less) of comparatively unorganised Energetic material. As in the case of the plant, the material may differ in amount, but must be sufficient, under the liberating agency of heat, to carry on the process of organisation to such a point that the young organism can obtain THE AMMAL ORGANISM 149 the necessary further material for itself. In the case of a bird, this material is supplied by the food-yolk ; in that of a mammal it is supplemented by nutriment derived from the maternal circulatlnfr system. But in eyery case, the young plant and the young animal are alike in this, that each begins its life as an ex- l)ender of previously-accumulated Energy. It is needless to add that the presence of free oxygen, which combines with the food-slufls to ])roduce carbonic anhydride, and so yields up its Energy for the act of organisation, is in both cases indispen- sable. So soon, however, as the self-sustaining de- gree of organisation has been reached, a wide diffe- rence begins to manifest itself. The plant spreads its leaves to the sun and the air, and drinks in carbonic anhydride and water, from which the ethereal Enero-y separates part of their oxygen, and manufactures starch and other organic compounds. The animal, on the contrary, devours the compounds thus formed, and drinking in the free oxygen, causes them to re- aggregate within his body, using up the Energy so liberated, partly for the production of heat, partly for physiological processes, and partly for locomotion. What may be the exact nature of these conversions w^e do not fully know ; and even if w^e did, they could only be detailed in a complete work on Physiolofry : but it is sufficient for our purpose to point out (hat ISO CONCRETE OR SYXTIIETIC Energetic carbonaceous and nitrogenous matters pass into the body by one channel, and free oxygen by an- other ; tliat they leave the body as carbonic anhydride, ammonia, water, and other de-energised products ; and that heat and motion have been given outmeanwliile. The animal organism is thus essentially a seat for the reaggregation of matter and the dissipation of Energy. It is, however, probable that part of the Energy thus liberated is not immediately dissipated, but is used up for the time being in the so-called syn- thetic processes of the body. What these really are, we do not thoroughly understand : but it seems lilcely that they may be combinations of many atoms, pos- sessing high relative Kinetic Energy, upon whose de- composition the Kinetic Energy is liberated.^ Thus, a manifestation of Energy accompanies the conversion of sugar into lactic acid, or into alcohol and carbonic anhydride, although no new oxygen is united during the process. At any rate, waiving all speculation, it is <*ertain that these bodies, unlike ordinary com- pounds, possess Energy in their composite form, which is dissipated when the}^ separate into simpler bodies. While the animal lives, he is perpetually taking into his organism Energetic Compounds stored up in plants, or temporarily deposited in the tissues of other ' This the author now greatly doubts. THE ANIMAL ORGANISM 151 animals, and using up their Enerpries for his own activities. In some cases the matters thus ahsorlx'd are inunediately employed for physiological processes : but in other cases they are stored up, like the starch and albumen of seeds or tubers, for future use. A bear living through the winter on his own fat, or a camel consuming his humps during a journey, is the exact analogue of the sprouting wheat and of the potato or hyacinth grown in a cellar. When the animal dies, heat and other animal germs act as liberators for his stored-up tissue Energies ; and de- composition rapidly sets in, resulting in the final formation of stable compounds. Thus the matter which during the animal's life possessed Energy of chemical separation in its atomic composition, — Energy of molar separation in its erect position and frequent elevation in the air or on mountain tops, — Energy of molecular motion in its heat, — and Energy of molar motion in its locomotive processes, — becomes at last a number of chemically stable masses, partly aggregated with the earth's surface, and partly float- ing as carbonic anhydiide, incapal)le of resuming its separate and self-moving condition except by the intervention of fresh solar Energy through the agency of vegetal life. Viewed from a wide standpoint, we may say that animals act as liberating agents for the Enern^ies isa coxcKEm ok synthetic stored \\\) in plants. Thoy are therefore links in that general chain of j)rocesses whereby separate portions of matter are made to aggregate in the stablest union, and their ])revioiisly-existing separation is imparted lo the ether. '53 CHAPTER VIIT. OKNKRAL VI KW OF MUNDANE ENERCilKS. We have now coini)leted our brief survey of the cos- niical facts known to us at present, and examined their congruity with our general theory of two opposing Powers, aggregative and separative. But before we close the subject it may be well to look briefly at the facts of mundane Energy in their entirety, with especial reference to the part played by man. By the term ' Cosmical Energies of the J^arth ' we may understand all that Energy which our planet possesses in virtue of its statical separation from the sun and the other sidereal bodies. By the term ' Proper Energies of the Earth ' we may designate all that Energy which the material particles composing the earth's substance now possess or formerly pos- sessed in virtue of their own original separation from one another, as masses, molecules, or atoms. Finally, bv the term 'Derived Energies of the Earth,' we may understand all that Energy which our planet has ab- 154 cose RET E OR SYNTHETIC iSorbcd from the radiated Energy of other aggregathig masses elsewhere : and as the amount of such absorbed Energy derived from the ' fixed ' stars or refle(;ted from the moon and planets is practically without conspi- cuous effects on the earth's surface, we may consider this term as equivalent to directly incident solar Energy. The Cosmical Energies need not long detain us. Doubtless, as the earth loses orbital Energy by ethe- real friction, it is slowly approaching the sun, while the sun in turn is approaching its own central point of attraction ; but these remote possibilities possess for man only a speculative interest, and have no in- fluence on practical mechanical activities. The Proper Energies of the Earth are more inte- resting to humanity. (1) First, come the facts of the planet's orbital Energy and nutation, which in- directly yield the phenomena of winter and summer. (2) Next comes its axial motion (the indirect cause of day and night ),^ of whose dissipation the tides are a concomitant. (3) More purely terrestrial are the phenomena of earthquakes, volcanoes, &c., which are Kinetic transformations of the statical separation existing between the superficial and central masses. ' Indirect, because the real cause is the incident sunlight. Were there no sun, the axial energy might still continue, but not, of course, the daylight. GENERAL VIEW OF MUXDAXE ESERGIES 155 (4) Derived from tlie last-njimcd Kiierjjry 18 the Po- tential Enorjrv of mountains and otlier masses raised by lateral pressure above the rjeneral level of the solid and liquid surface. In both these eases, — that of the whole cohering crust, and that of special raised masses — small por ions of the Potential Enerjjfy become from time to time Kinetic under the influence of liberating Jigencies ; in the first case, we know the result as an earthquake, in the second as a landslip. (5) Next may be mentioned the internal heat of the earth, small portions of which are always escaping by con- duction through the cohering crust. (6) Lastly, we may mention the Potential I*]nergy of chemical sepa- ration in free elements, like sulphur &c., within the earth's crust, if these ought not to be regarded as of organic origin, and consequently included in the list of Derived Energies. All these Proper Energies are the surviving forms of the separation once exist- ing between the various portions of our earth. (But in the case of the cohering crust, the monntains, and the free elements, the Energies remain as statical se- parations to our own time. In the case of the orbital and axial Energies, the separation has assumed the form of continuous molar motions. In the case of the internal heat, it has assumed tliat of continuous molecular motion.) And in every earthquake, land- slip, falling cliff, or tuml>!ing stone, we see these Po- 156 CO^CKICTK OK syW77//:77C tciitial Kiicrgles .•issuiiiiiig llic Kinetic Mode uiulcrour V€^ry eyes. Nor is it neressary to show in detail liow the earth is gradually i)arting with all these Proper I'Jiergies. The orbital and axial motions are being dissipated by ethereal friction or by the moon's attraction. The internal heat is being dissi- pated by (H)nduction. The Potential Energy of the crust is being given up from time to time by cart h- ([uakes, or, after assuming the form of heat in volcanic eruptions, is being radiated off into ether. And the mountains, cliffs, and other elevated portions locally raised for awhile (to outward appearance) by these widespread disturbances, aljove the general level, are being for ever woin down by rain, storms, roots, animal footsteps, and other results of those Derived Energies which we have next to examine. So that the remaining Proper Energies of the earth (most of them having been long since dissipated, after the paitial aggregation of its matter, dui-ing the cooling of its crust) are still being cast loose, in one form or another, upon the Energy-a])sorbing ether ; while a corresponding aggregation of its matter is for ever taking place. But the m-eat mass of those Mundane Enei'ijries in which man is directly interested Ijelong to the class of Derived Energies. And these, as we have al- ready (?eeii. may be considered as practically c([uiva- GICXKKA/. in: II' OF .UCXDAMC EXKNUI/iS 157 lent to the (liivctly-incidciit 8olar cncrjjy aiul its deri- vatives. They are dilliciilt to classify, ovviii<{ to tlieir rapid ehaii^^'es, hut the r()ll()\viii<,' division may cast some lij;lit oil tl»eir nature. Solar ICnergies are either l)ire(;t, as li^dit and radiant heat, or Absorbed, as in clouds, orn^anisnis, iSjc. Tiie latter or A])sorbed class may be a'^ain divided into those of Inorj/anic Orij^nii, and those of Organic; Origin. Each of these will de- mand separate treatment. Direct Solar Energy is the radiant Energy which from moment to moment is cast upon our planet from the sun. If the surface of the earth were composed of a perfectly reflecting non-absorbing substance, all tliis Energy would immediately be reflected back into space. As it is, a small portion is so reflected, but tlie greater part is absorbed by various superficial bodies in the production of motion and separation between their parts. Absorbed Solar Energy, emplo}'ed for Inorganic pnrposes, gives rise to the following among other phenomena. (1) The Energetic gaseous condition of the atmosphere. (2) The Energetic liquid condition of water in temperate climates. (0) The melting of ice. (4) The act of evaporation and raising of vapour. (5) The production of winds and storms. (6) The production of ocean currcjits. Some of these Ener- gies are Kinetic, as in the case of the gases, liquids. IS8 CONCRETE OR SYNTHETIC &c. : but ill other instances the Energy is rendered Potential for awhile, as in the case of the floating cloud, the head of water, and the ice or snow upon the mountain tops. And, finally, these Potential Energies are constantly becoming once more Kinetic, as when the rain falls, the river flows, and the glacier or ava- lanche slides down the valley. Each such Kinetic Energy is of course in the act of being dissipated, by friction or otherwise, to the ethereal medium. And as before notic^ed, these Inorganic Absorbed Energies become liberating agents for the proper Potential Energy of the Earth, when rain or rivers wear down rocks and mountains ; when glaciers or avalanches grind their bed and tear away the stones ; wdien storms beat the waves against the cliff; and when winds upset rocky masses. Moreover, they also act as liberating agents for Potential Energy of Organic Origin, when lightning, rain, or wind wears down and overthrows trees or buildings, when storms sink iron ships, and when avalanches overwhelm villages. Still more difficult to trace, because of their numerous involutions, are the vicissitudes of that Energy wdiicli assumes the Organic form. Yet we must endeavour to give some account of its main phases. The Energy which falls on the growing plant lays up Energetic Compounds in the i)lant's sulj- , stance and raises it to a position of visible height. GENERAL VIEW OF MUNDANE ENERGIES 159 Part of the Potential Energy thus obtained, the phmt uses up in its own processes : part remains for awhile inherent in its tissues. But, for the most part, sooner or later it is either devoured by an aninuil, or else dies. In the first case, the animal digests it, and uses up its Energy in its own processes as heat and motion. In the second case, fungi grow upon it, worms de- vour it, water disintegrates it, and in one way or another it yields up its Energy at last to ether. Be- sides the Energy thus stored up in existing organisms, there is some Energy belonging to extinct organisms yet remaining on our earth. The small amount which is stored up in wood, meat, Siberian mammoths, desic- cated diatoms, and other like forms, may be neglected on account of its insignificant quantity. But there are considerable stores of Energetic material, known as coal, peat, rock-oil, &c., which deserve a passing mention. These are so situated that without a liberating agent they could not be dissipated. Such a liberating agent they find in man, who is so rapidly using them up that he is now beginning to look forward to a future when all such stores will be exhausted, and when he will have to depend for his stock of Energy on the immediate daily supplies from the sun. As to the animal organisms, they are themselves entirely expenders of Energy, ;i,nd their whole life consists in a reaggregation of matter and l60 COXCRETE OR SYNTHETIC consequent dissipation of Energy. In one way, how- ever, such organisms leave portions of their Energy for awhile in a Potential form, namely by building. Every house, wall, church, &c., is a mass raised to a height by means of Energy : and it may retain its Energy, in the absence of a liberating agent, for a considerable time. But in the end. Solar Energy, in some one or other of its transformations, will act as a liberating agent to reduce these irregularities and wear down their masses. Either by rain, wind, fire, roots of trees, lightning, or the hand of man, every building sooner or later totters to the ground. And if it escapes all these, the earth's own Proper Energy may prove its overthrow, by tides, earthquakes, subsidences, or volcanic eruptions. So that, as in every other case, we see the matter ultimately aggregating and the Energy handed over to the all- absorbing ether. Thus the earth is for ever parting with its Energy in every shape. It is slowly aggregating Mdth the sun and the fixed stars. It is losing its orbital and axial motions. By internal cooling, by subsidences, earthquakes, and volcanic eruptions, by radiation from lava and hot springs, it is getting rid of the proper separation and motion inherent in its own mass. Solar Energy falling upon it prevents ^nd counteracts for awhile its total aggregation,— liquefies ^ GENERAL VIEW OF MUXDANE ENERGIES i6i the ocean, keeps the atmospliere gaseous, creates winds and currents, piles ice on mountain-tops, stores up Energetic Compounds in vegetal and animal oriia- nisms, lays by coal and peat, builds castles and cathe- drals, smelts iron, and separates chemical bodies in phials and jars. But this very same Solar Ener<rv acts as a liberating agent in the long run not oidy for its own Potentially-Energetic products, but also for the proper Tot ential Enei-gy of the earth. It wears down cliffs, moui ains, and table-lands, it melts the ice and snow on the mountains, it sets the animal to devour the plant ; it drives num to dig and burn the coal and petroleum ; it overthrows the buildings he has piled ; it rusts his iron implements ; it corrodes his chemical reagents. 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Fcp. 8vo. 2s. 6</. each. Tucker's (Rev. II. W.)Tlie English Church in other Lands. Perry's (Rev. G. G.) The History of the Reformation in England. BrndiicU's (lion. G. C.) A History of the University of Oxford. Mullirgcr's (J. B ) A History of the Univer- sity of Cambridge. Plummer's (A.) The Church of the Early Fathers. Carr's (Rev. A.) The Church an I the Roman Empire. Wakeman's (H. O.) The Church and the Puritans (1570- 1660). Overton's (Rev. J. H.) The Evangelical Revival in the Eighteenth Century. Tozer's (Rev. H. F.) The Church and the Eastern Empire. fUKUSHKD Bv Mrssrs. /.o.\r,.uA\s, Gutity. » Co, Epochs of Church History— roiitinued. Stephens's (Rev. W. R.W.) Ilildcbrand ami his Times, Hunt's (Rev. W.) The English Church in the Middle Arcs. Balzani's (U.) The Topes and the Ilohcn- staufcn. Gwatkin's (11. M.) The Arian Controversy. Ward's (A. W.) The Counter- Reformation. Toole's (R, L.) WyclifTc and Karly Move- ments of Reform. Epochs of Ancient History. Edited l.y the Rev. Sir C. W. Cox, Hart. M.A. and by C. Sankey, M.A. lo volumes, fcp. 8vo. with Map», 2s. 6d. each. Ccesly's (A. II.) The (Iracchi, Marius, and Sulla. With 2 Maps. Cai)es's (Rev. AV. \S.) The Early Roman Empire. I'rom the Assassination of Julius C.xsar to the Assassination of Domiiian. With 2 Maps. ■ The Roman Empire of the Second Cenlur)', or the Age of the Antonincs. With 2 Maps. Cox's (Rev. Sir C. W.) The Athenian Empire from ll;e I'liRht of Xerxes to the Fall of Athens. With 5 Maps. ___ The Ci reeks and the Tersiar.s. With 4 Maps. Cuiteis's (A. M.) The Rise of the Mace- donian Empire. With 8 Maps. Ihne's (W.) Rome to its Capture i)y the (iauls. \Vilh a Map. Merivale's (\ery Rev. C.) The Roman Triumvirates. With a Map. Sankey's (C.) The Spartan and Tlieban Supremacies. With 5 Maps. Smith's (K. 15) Rome .and Carthngc, the Punic Wars. With 9 .Maps and I'lans. Epochs of American History. Edited i>y Dr.Al.liKRT I!i siinki.i. Haki, Assistant Trofessor of History in liarvanl College. Thwaites's (R. C.) The Colonies (1492- 1763). I'cp. 8vo. y. Gil. [A'eai/y. Hart's (A. R.) Formation of the Union (176J-1829). Fcp. 8vo. \In preparation. Wilson's (W,) Division and Re-union (1829-1889). Fcp. 8vo. [/n preparation. Epochs of English History. Complete iu One V'tjTuine, with 27 Tables and I'edigrces, and 23 Maps. Fcp. 8vo. *f^* For details of Tarts see Longmans & Co. 'a Catalogue of School liuoks. EWALD (Heinrich)— Works by. The Antiquities of Israel. Trans- lated from the German i)y H. S. SOLLY, M.A. 8vo. izr. bJ. The History of Israel. Trans- lated from the German. 8 vols. 8vo. Vols. I. and II. 24r. Vols. III. and IV. 21/. Vol. V. i%s. Vol. VI. 16/. Vol. VII. 2ir. Vol. VIII. with Index to the Complete Work. 181. FAR NELL. The Greek Lyric Poets. Edited, with Introduction* and Notes, by G. S. Farnell, .M..\. 8vo. FAR RAR.— Language and Lan- guages. A Revised Edition of Chtt" tets on Lanj^iai^e an/ Families of Sf<etyh. ByF. W. FARkAR, D.D. Crown 8vo. 6*. FIRTH.— Nation Making: a .Storv of New /,<Mland .Savni eir.m and Civil- isation. I'.y I, C. FiKiii, Author <>'' •Luck' .anil 'Oar Kin across the Sea. ' Crown Svo. Gs. FITZWYGRAM.— Horses and Stables. By Maj( r-C.eneral Sir F. Fi^.zwYc.RAM, Bart. With 19 pages of Illustrations. 8vo. 5x. FORD.— The Theory and Prac- tice of Archery. BythelatelloRAdl Ford, New Edition, thoroughly Revised and Re written by W. Bu IT, M.A. With a Preface by C, J. LuNGMAN, M.A. F.S.A. 8vo. 14/. FOUARD.— The Christ the Son of God: a Life of our Lord and Savii ur Jesus Christ. By the Abbe Constant FnfARD. Translated from the Fifth Edition, with the Author's sanction, bv GE'irckF. X. GiUFiiTii. With an Intri- duction by Cardinal M.VNMNu. 2 vols. crown Svo. la^s. FOX.— The Early History of Charles James Fox. By the Right Hon. SirG. (\Trevelyan, Bait. Library Edition, Svo. \%s. Cabinet Edition, cr. Svo. 6/. FRANCIS— A Book on Angling; or. Treatise on the Art of Fishing in e\ery branch; including full Illustrated list of .Salmon Flies. I'y Francis Francis. Post Svo. I'ortrait rnd I'lates, 15^. FREEMAN.-The Historical Geo- graphy of Europe. By e. a. Freeman. Wah 65 Maps. 2 vols. Svo. 2 IX. 6</. A3 10 A Catalogub of Books /.v Gbxbkai. Literati-rb FROUDE (James A.)-Works by. The History of England, from the Fall of Wolscy to the DcfL-at of the Spanish Armada. 12 vols, crov.n 8vo. £2. 2s. Short studies on Great Sub- jects. Cabinet lulition, 4 vols, crown 8vo. 24T. Cheap Edition, 4 vols, crown 8vo. 31. (hi, cacli. Cxsar : a Sketch. Crown 8vo. y. dd. The English in Ireland in the Eighteenth Century. 3 vols. crown 8vo. i8j. Oceana ; or, England and Her Colonies. Withg illustrations. Crown 8vo. 2s, boards, 2s. 6J. cloth. The English in the West Indies; or, tlie How of Llysscs. With 9 Illustrations. Crown fivo. 2s. boards, 2s. 6/. cloth. The Two Chiefs of Dunboy; an Irish Roiuancc of ihii Last CeiUury. Crown 8vo. 6s. Thomas Carlyle, a Historj' of his Life. 1795 to 1S35. 2 vols, crown 8vo. 7^. 1S34 to i8Si. 3 vols, crown Svo. 7^. G A LLWEY.— Letters to Young Shooters. (First Scries.) On the C"h(iice and Uscof adiin, IJy Sir RAI.I'II rAVNE-GALLWKV, T.ait. \Vith Illustra- tions. Crown Svo. 7^. GJ. GARDINER (Samuel Rawson)— Works by. History of England, from the Accession of James I. to the Outbreak of the Civil War, 1603-1642. 10 vols, crown Svo. price 6^. each. A History of the Great Civil War, 1642-1649. (3 vols.) Vol. I. 1642-1644. With 24 Maps. Svo. 2IJ. (out of prim). Vol. II. 1644 -1647. With 21 Maps. Svo. 24J. The Student's History of Eng- land. Illustnited under the superin- tendence of Mr. St. John IIorE, Secretary to the Society of Antiipiaries. Vol. I. H.c. 55— A. D. 1509, with 173 Illustrations, crown Svo. 4.f. Vol. II. 1509-1689, with 96 Illustrations. Crown Svo. 4J. The work will be published in Three Volumes, and also in One Volume complete. GIBERNE— Works by. Ralph Hardcastle's Will. By Agnes Giukkne. With Frontispiece. Crown Svo. 5/. Nigel Browning. Crown Svo. 5^. GOETHE.- Faust. A New Transla- tion chiefly in Blank Verse ; with Intro- duction and Notes. By jAMIiS AUEY Birds. Crown Svo. 6 j. Faust The Second Part. A New Translation in Verse. By James Auey Birds. Crown Svo. Cs. GREEN.-The Works of Thomas Hill Green. Edited by R. L. Nettle- siiii' (3 vols.) Vols. 1. and II. — Philosophical Works. Svo. i6j. each. Vol. III.— Miscellanies. With Index to the three Volumes and Memoir. Svo. 2\s. The Witness of God and Faith : Two Lay Sermons. By T. II. GiiKEN, Fcp. Svo. 2J. GREVILLE. — A Journal of the Reigns of King George IV. King William IV. and Queen Victoria. By C. C. F. Creville. Fdiledbyll.REEVE. Svols. Cr.Svo.6/.ea. GREY.— Last Words to Girls. On Life in School and after School. By Mrs. William Grey. Cr Svo. 3^. 6./. 6WILT. — An Encyclopaedia of Architecture. By Joseph Gwilt, F.S.A. Illustrated with more th.in 1,700 Engravings on Wood. Svo. 52^. dd. 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Harrison. 8vo. iSf. HARRISON. — The Contemporary History of the French Revo- lution, compiled from tlie ' Annual Register.' IJy F. Baykoru Harrison. Crown Svo. },s. 6J. HARTE (Bret)-Works by. In the Carquinez Woods. Fcp. 8vo. I J. boards ; n. 6J. cloth. On the Frontier. i6mo. is. By Shore and Sedge. i6mo. is. HARTWIG (Dr.)— Works by. The Sea and its Living Wonders. \Vith 12 Plates and 303 Woodcuts. Svo. I Of. 6 J. The Tropical World. With 8 Plates, and 172 Woodcuts. Svo. lOs. 6d. The Polar World. With 3 Maps, 8 Plates, and 85 Woodcuts. Svo. loj. fxi. The Subterranean World. With 3 Maps and 80 Woodcuts. Svo. loj. 6d. Ihe Aerial World. With Map, 8 Plates, and 60 Woodcuts. Svo. 10/. bJ. The following books are extracted from the foregoing works by Dr. Hartwig : — Heroes of the Arctic Regions. With 19 Illustrations. Crown Svo. 2s. Wonders of theTropicalForests. With 40 Illustrations. Crown Svo. 2s. Workers Under the Ground. or. Mines and Mining. With 29 lilus-- trations. 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Verse Translations : Ninctttn Passages fio'u Lucretius, Horace, llon-cr, \c. Cro'.\n 8vo. 8^. M. HOW ITT.— Visits to Remarkable PlaceS,01(l Halls, Kail le-Fiel«ls, Scenes illustrative of Striking Passages in English History and Poetry. Py William HowiTT. 80 Illustrations. Cr. 8vo, 3J. 6</. HULLAH (John)— Works by. Course of Lectures on the His- tory of Modern Music. Svo. 8f. 6</. Course of Lectures on the Tran- sition Period of Musical History. 8vo. icw, 6./. HUM E.— The Philosophical Works of David Hume. Eiiited byT. h. Green and T. H. Grose. 4 vols. 8vo. 56J. Or separately, Essays, 2 vols. 28/. Treatise of Human Nature. 2 vols. 28^. HUTCHINSON (Horace) -Works by. Cricketing Saws and Stories. liy Horace Hi iciiinson. •\Vith fLCtilincar Illustrations by the Author. lonio. is. Some Great Golf Links. Edited by Horace Hutchinson. With Illus- trations. Tiiis book is mainly a reprint of articles that have recently appeared in the Saturday Kcvic'M, HUTH— The Marriage of Near Kin, considered with respect to the Law of Nations, the Result of Experience, and the Teachings of Biology. By Alfred H. Hltii. Royal 8vo. 2Ij. INGELOW (Jean)-Works by. Poetical Works. Vols. L and II. Fcp. 8vo. \2s. Vol. III. Kcp. 8vo. 5j. Lyrical and Other Poems. Se- lected from the Writings of Jean Inuelow. Fcp. 8vo. 2x. Ci. cloth plain ; 3r. cloth gilt. Very Young and Quite Another Story : Two stories. Crown Svo. f>s. JAME8. The Long White Moun- tain^ or, a Jdurncy in Nfanchuria, with an Account of ti.e History, Administra- lion, and Reii^,'i()n of that Piovincc. By H.E James. With lUujilrations. 8V0.24J. JAMESON (Mrs.) -Works by. Legends of the Saints and Mar- tyrs. With 19 Etchings nnd 187 \Yoo«l. cuts. 2 vols. Svo. 2)'. Hit. Legends of the Madonna, the \ Hgin M.ir) as feinescnted in Sacred and Legendary Art. Willi 27 Etchin(}s and 165 Woodcuts. 1 vol. 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JUSTINIAN.- The Institutes of Justinian ; Latin Text, chiefly that of Huschke, with English Introduction. Translation, Notes, and .Summary. By Thomas C. Sanuars, M.A. Svo. i8j. KALISCH (M. M.)-Works by. Bible Studies. Part I. The Pro- fhecits of Balaam. Svo. loj, (yi. Part I. The Book of Jonah. Svo lor. W. PUBUSHBD BY AfsSSMS. LONOUASS, GmBBX, ^ CO. t} KALI8CH (M. M.)— Works by— ««/./. Commentary on the Old Testa- ment; with a New Translation. Vol. I. Genesis, 8vo. lis, or adapted for the General Reader, I zr. Vul. II. Exodus, 15X. or adapted for the General Reader, \2s. Vol. III. Leviticus, Part I. 15/. or adapted for the General Recder, &r. Vol. IV. Leviticus, Part II. 1$^. or adapted for the General Reader, &r. Hebrew Grammar. With Exer- cises. Part I. 8vo. 12s. 6J Key, 5/. Part II. I2s. 6t/. KANT (Immanuel)— Works by. Critique of Practical Reason, and other Works on the Theory of Ethics. Translated by T. K. Abbott, U. D. 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