The Evolution of Matter - the book The Evolution of Matter - Table of Contents
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CHAPTER I.
INTRA-ATOMIC ENERGY - ITS MAGNITUDE.
§ I. The Existence of Intra-atomic Energy.
I HAVE given the name of Intra-atomic Energy to the new force, differing entirely from those hitherto observed, which is produced by the dissociation of matter - that is to say, by the whole series of radio-active phenomena. From the chronological point of view, I ought evidently to commence by describing this dissociation; but as intra-atomic energy governs all the phenomena examined in this work, it seems to me preferable to begin by its study.
I shall therefore suppose an acquaintance with the facts concerning the dissociation of matter which I shall set forth later, and shall confine myself at present to recalling one of the most fundamental of these facts - the emission into space, from bodies undergoing dissociation, of immaterial particles animated by a speed capable of equalling and even of often exceeding a third of the speed of light. That speed is immensely superior to any we can produce by the aid of the known forces at our disposal. This
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is a point which must be steadily kept in mind from the first. A few figures will suffice to make this difference evident.
A very simple calculation shows, in fact, that to give a small bullet the speed of the particles emitted by matter in process of dissociation would require a firearm capable of containing one million three hundred and forty thousand barrels of gunpowder.[1] As soon as the immense speed of the particles emitted was measured by the very simple methods I describe elsewhere, it became evident that an enormous amount of energy is liberated during the
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dissociation of atoms. Physicists then sought in vain and many are still seeking the external source of this energy. It was understood, in fact, to be a fundamental principle that matter is inert and can only give back, in some form or other, the energy which has first been supplied to it. The source of the energy manifested could therefore only be external.
When I proved that radio-activity is a universal phenomena and not peculiar to a small number of exceptional bodies, the question became still more puzzling. But, as this radio-activity is above all manifested under the influence of external agents - light, heat, chemical forces, etc. - it is comprehensible that we should seek for the origin of this proved energy among these external causes, though there is no comparison between the magnitude of the effects produced and their supposed causes. As to spontaneously radio-active bodies, no explanation of the same order was possible, and this is why the question set forth above remained unanswered and seemed to constitute an inexplicable mystery. Yet, in reality, the solution to the problem is very simple. In order to discover the origin of the forces which produce the phenomena of radio-activity, one has only to lay aside certain classical dogmas. Let us first of all remark that it is proved by experiments that the particles emitted during dissociation possess identical characteristics, whatever the substance in question and the means used to dissociate it. Whether we take the spontaneous emission from radium or from a metal under the action of light, or again from a Crookes' tube, the particles emitted are similar. The origin of the energy which produces the observed effects seems therefore to be always the same. Not being
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external to matter, it can only exist within this last.
It is this energy which I have designated by the term intra-atomic energy. What are its fundamental characteristics? It differs from all forces known to us by its very great concentration, by its prodigious power, and by the stability of the equilibria it can form. We shall see that, if instead of succeeding in dissociating thousandths of a milli-gramme of matter, as at present, we could dissociate a few kilogrammes, we should possess a source of energy compared with which the whole provision of coal contained in our mines would represent an insignificant total. It is by reason of the magnitude of intra-atomic energy that radio-active phenomena manifest themselves with the intensity we observe. This it is which produces the emission of particles having an immense speed, the penetration of material bodies, the apparition of X rays, etc., phenomena which we will examine in detail in other chapters. Let us confine ourselves, for the moment, to remarking that effects such as these can be caused by none of the forces previously known. The universality in nature of intra-atomic energy is one of its characteristics most easy to define. We can recognize its existence everywhere, since we now discover radio-activity everywhere. The equilibria it forms are very stable, since matter dissociates so feebly that for a long time one could believe it to be indestructible. It is, besides, the effect produced on our senses by those equilibria that we call matter. Other forms of energy - light, electricity, etc., are characterized by very unstable equilibria.
The origin of intra-atomic energy is not difficult
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to elucidate, if one supposes, as do the astronomers, that the condensation of our nebula suffices by itself to explain the constitution of our solar system. It is conceivable that an analogous condensation of the ether may have begotten the energies contained in the atom. The latter may be roughly compared to a sphere in which a non-liquefiable gas was compressed to the degree of thousands of atmospheres at the beginning of the world.
If this new force - the most widespread and the mightiest of all those of nature - has remained entirely unknown till now, it is because, in the first place, we lacked the reagents necessary for the proof of its existence, and then, because the atomic edifice erected at the beginning of the ages is so stable, so solidly united, that its dissociation - at all events by our present means - remains extremely slight. Were it otherwise the world would long ago have vanished.
But how is it that a demonstration so simple as that of the existence of intra-atomic energy has not been made since the discovery of radio-activity, and especially since I have demonstrated the generality of this phenomenon? This can only be explained by bearing in mind that it was contrary to all known principles to recognize that matter could by itself produce energy. Now, scientific dogmas inspire the same superstitious fear as did the gods of old, though they have at times all their liability to be broken.
I have said a few words as to the magnitude of intra-atomic energy. Let us now try to measure it.
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The following figures will show that, whatever may be the method adopted, we arrive, by measuring the energy liberated by a given weight of dissociated matter, at totals immensely superior to all those obtained by hitherto known chemical reactions - the combustion of coal, for example. It is for this reason that substances, in spite of the slightness of their dissociation, are able to produce during this phenomenon the intense effects which I have to enumerate.
The different methods in use for measuring the speed of the particles of dissociated matter, whether radium or any metal whatever, have always given nearly the same figures. This speed is almost that of light for certain radio-active emissions. For others we get a third of that speed. Let us take the lesser of these figures, that of 100,000 kilometres per second, and endeavour, on that basis, to calculate the energy that would result from the complete dissociation of one gramme of any matter we please.
Let us take, for instance, a copper one-centime piece, weighing, as is well known, one gramme, and let us suppose that by accelerating the rapidity of its dissociation we could succeed in totally dissociating it.
The kinetic energy possessed by a body in motion being equal to half the product of its mass by the square of its speed, an easy calculation gives the power which the particles of this gramme of matter, animated by the speed we have supposed, would represent. We have, in fact,
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millions of kilometers, figures which correspond to about six thousand eight hundred million horse-power if this gramme of matter were stopped in a second. This amount of energy, suitably disposed, would be sufficient to work a goods train on a horizontal line equal in length to a little over four times and a quarter the circumference of the earth.[1]
To send this same train over this distance by means of coal would take 2,830,000 kilogrammes, which at 24 francs a ton, would necessitate an expenditure of about 68,000 francs. This amount of 68,000 francs represents, therefore, the commercial value of the intra-atomic energy contained in a one- centime coin.
What determines the greatness of the above figures and makes them at first sight improbable is the enormous speed of the masses in play, a speed which we cannot approach by any known mechanical means. In the factor mV2, the mass of one gramme is certainly very small, but the speed being immense the effects produced become equally immense. A rifle-ball falling on the skin from the height of a few centimetres produces no appreciable effect in consequence of its slight speed. As soon as this speed is increased, the effects become more and more deadly, and, with the speed of 1000 metres per second given by the powder now employed, the
[1] I take, in this calculation, a normal goods train, comprising 40 trucks of 12 1/2 tons, say, a weight of 500 tons, journeying at a speed of 36 kilometres per hour on the level, and necessitating a haulage force of 6 kilogrammes per ton per second - or 3000 kilogrammes for the 500 tons. The force given out by the engine pulling this train at a speed of 36 kilometres would amount to 400 h.p. At the rate of 1 1/2 kilos of coal per unit and per hour, there would be consumed in 4,722 hours (duration of the journey) 4,722 x 400 x 1. 5 =2,830,000 kilogrammes.
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bullet will pass through very resistant obstacles. To reduce the mass of a projectile matters nothing if one arrives at a sufficient increase in speed. This is exactly the tendency of modern musketry, which constantly reduces the calibre of the bullet but endeavours to increase its speed.
Now the speeds which we can produce are absolutely nothing compared with those of the particles of dissociated matter. We can barely exceed a kilometre per second by the means at our disposal, while the speed of radio-active particles is 100,000 times greater. Thence the magnitude of the effects produced. These differences become plain when one knows that a body having a velocity of 100,000 kilometres per second would go from the earth to the moon in less than four seconds, while a cannon ball would take about five days.
Taking into account a part only of the energy liberated in radioactivity, and by a different method, figures inferior to those given above, but still colossal, have been arrived at. The measurements of Curie prove that one gramme of radium emits 100 calorie-grammes an hour, which would give 876,000 calories per annum. If the life of a gramme of radium is 1000 years, as is supposed, by transforming these calories into kilogrammetres at the rate of 1123 kilogrammetres per great calorie, the immensity of the figures obtained will readily appear. Necessarily, these calories, high as is their number, only represent an insignificant part of the intra-atomic energy, since the latter is expended in various radiations.
The fact of the existence of a considerable condensation of energy within the atoms only seems to jar on us because it is outside the range of things
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formerly taught us by experience; it should, however, be remarked that, even leaving on one side the facts revealed by radioactivity, analogous concentrations are daily observable. Is it not strikingly evident, in fact, that electricity must exist at an enormous degree of accumulation in chemical compounds, since it is found by the electrolysis of water that one gramme of hydrogen possesses an electric charge of 96,000 coulombs? One gets an idea of the degree of condensation at which the electricity existed before its liberation, from the fact that the quantity above mentioned is immensely superior to what we are able to maintain on the largest surfaces at our disposal. Elementary treatises have long since pointed out that barely a twentieth part of the above quantity would suffice to charge a globe the size of the earth to a potential of 6000 volts. The best static machines in our laboratories hardly give forth 1/10,000 of a coulomb per second. They would have, consequently, to work unceasingly for a little over thirty years to give the quantity of electricity contained within the atoms of one gramme of hydrogen.[1]
As electricity exists in a state of considerable concentration in chemical compounds, it is evident that the atom might have been regarded long since as a veritable condenser of energy. To grasp thereafter the notion that the quantity of this energy must be enormous, it was only necessary to appreciate the magnitude of the attractions and repulsions which
[1 They would indeed make this output at tensions of about 50,000 volts, so that the power produced (volts \ amperes) would greatly exceed, at the end of thirty years, the power generated by 96,000 coulombs under a pressure of one volt.]
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are produced by the electric charges before us. It is curious to note that several physicists have touched the fringe of this question without perceiving its consequences. For example, Cornu pointed out that if it were possible to concentrate a charge of one coulomb on a very small sphere, and to bring it within one centimetre of another sphere likewise having a charge of one coulomb, the force created by this repulsion would equal 918 dynes, or about 9 billions of kilogrammes.[1]
Now, we have seen above that by the dissociation of water we can obtain from one gramme of hydrogen an electric charge of 96,000 coulombs. It would be enough - and this is exactly the hypothesis lately enunciated by J. J. Thomson - to dispose the electric particles at suitable distances within the atom, to obtain, through their attractions, repulsions, and rotations, extremely powerful energies in an extremely small space. The difficulty was not, therefore, in conceiving that a great deal of energy could remain within an atom. It is even surprising that a notion so evident was not formulated long since.
Our calculation of radio-active energy has been made within those limits of speed at which ex-
[1] These figures of Cornu's only give the amount of the force of repulsion between two spheres. We can calculate the amount of power such a force as the above would yield in given conditions of time and space. If we suppose that the distance between the two spheres passes under the influence of the force in question are from 1 centimeter to 1 decimeter in 1 second, the power produced will be represented in C.G.S. units by the formula -
Converted into kilogram-meters, this formula gives 82 thousand million and a half kilogram-meters, or over one thousand millions h.p. per second.
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periments show that the inertia of these particles does not sensibly vary, but it is possible that one cannot assimilate their inertia - though this is generally done - to that of material particles, and then the figures given might be different. But they would none the less be extremely high. Whatever the methods adopted and the elements of calculation employed - velocity of the particles, calories emitted, electric attractions, etc. - one arrives at figures differing from each other indeed, but all extraordinarily high. Thus, for example, Rutherford fixes the energy of the u particles of thorium at six hundred million times that of a rifle-ball. Other physicists who, since the publication of one of my papers have gone into the subject, have reached figures sometimes very much higher. Assimilating the mass of electrons to that of the material particles, Max Abraham arrives at this conclusion: "That the number of electrons sufficient to weigh one gramme carry with them an energy of 6 x 1o13 joules." Reducing this figure to our ordinary unit, it will be seen to represent about 80,000,000,000 horse-power per second, about twelve times greater than the figures I found for the energy emitted by one gramme of particles with a speed of 100,000 kilometres per second.
J. J. Thomson also has gone into estimates of the magnitude of the energy contained in the atom, starting with the hypothesis that the material atom is solely composed of electric particles. His figures, though also very high, are lower than those just given. He finds that the energy accumulated in one gramme of matter represents 1.02 x 1019 ergs, which would be about 100,000,000,000 kilogram-
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metres.[1] These figures only represent, according to him, "an exceedingly small fraction" of that possessed by the atoms at the beginning and gradually lost by radiation.
Under what forms can intra-atomic energy exist, and how can such colossal forces have been con- centrated in very small particles? The idea of such a concentration seems at first sight inexplicable, because our ordinary experience tells us that the extent of mechanical power is always associated with the dimensions of the apparatus concerned in its production. A 1000 h.p. engine is of considerable volume. By association of ideas we are therefore led to believe that the extent of mechanical energy implies the extent of the apparatus which produces it. But this is a pure illusion consequent on the weakness of our mechanical systems, and easy to dispel by very simple calculations. One of the most elementary formulas of dynamics teaches us that the energy of a body of constant size can be increased at will by simply increasing its speed. It
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is therefore possible to imagine a theoretical machine composed of the head of a pin turning round in the bezel of a ring, which, notwithstanding its smallness, should possess, thanks to its rotative force, a mechanical power equal to that of several thousands of locomotives.
To fix our ideas, let us suppose a small bronze sphere (density 8.842), with a radius of three millimetres and consequently of one gramme in weight. Let us suppose that it rotates in space round one of its diameters with an equatorial speed equal to that of the particles of dissociated matter (100,000 kilogrammes per second), and that, by some process or other, the rigidity of the metal has been made sufficient to resist this rotation. Calculating the vis viva of this sphere it will be seen to correspond to 203,873,000,000 kilogrammetres. This is nearly the work that 1,510 locomotives averaging 500 h.p.[1] apiece would supply in an hour. Such is
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the amount of energy that could be contained in a yery small sphere animated by a rotatory movement of which the speed should be equal to that of the particles of dissociated matter. If the same little ball turned on its own centre with the velocity of light (300,000 kilogrammes per second) which represents about the speed of the ß particles of radium, its vis viva would be nine times greater. It would exceed 1,800,000,000,000 kilogrammetres and represent the work of one hour by 13,590 locomotives, a number exceeding all the locomotives on all the French lines.[1]
It is precisely these excessively rapid movements of rotation on their axis and round a centre that the elements which constitute the atoms seem to possess, and it is their speed which is the origin of the energy they contain. We have been led to suppose the existence of these movements of rotation by various mechanical considerations much anterior to the discoveries of the present day. These last have simply confirmed former ideas and have re-trans-
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ferred to the elements of the atom the motion which was attributed to the atom itself at a time when it was considered indivisible. It is only, no doubt, because they possess such velocities of rotation that the elements which constitute the atoms can, when leaving their orbits under the influence of various causes, be launched at a tangent through space with the velocities observed in the emissions of particles of matter in course of dissociation.
The rotation of the elements of the atom is moreover the very condition of their stability, as it is for a top or for a gyroscope. When under the influence of any cause the speed of rotation falls below a certain critical point, the equilibrium of the particles becomes unstable, their kinetic energy increases and they may be expelled from the system, a phenomenon which is the commencement of the dissociation of the atom.
The last objections to the doctrine of intra-atomic energy are daily disappearing, and it is now hardly contested that matter is a prodigious reservoir of energy; while the search for the means of easily liberating this energy will surely be one of the most important problems of the future. It is important to notice that, although the numbers above arrived at in various ways point out the existence in matter of immense forces - so unforeseen hitherto - they by no means imply that these forces are already at our disposal. In fact the substances which dissociate quickest, like radium, only disengage very minute quantities of energy. All those millions of kilogrammetres which a simple gramme of matter contains
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amount in reality to very little if, to obtain them, we have to wait millions of years. Suppose a strong box containing several thousand millions of gold dust to be closed by a mechanism which only permits the daily extraction of a milligramme of the precious metal. The owner of that strong box, notwithstanding his great wealth, would be in reality very poor, and would remain so, so long as his efforts to discover the secret of the mechanism by which he could open it were unsuccessful.
This is our position as regards the forces enclosed in matter. But, to succeed in capturing them, it was first necessary to be acquainted with their existence, and of this one had not the least idea a few years ago. It was even thought very certain that they did not exist. But shall we succeed in easily liberating the colossal power which the atoms conceal in their bosom? No one can foresee this. No more could any one say in the days of Galvani that the electrical energy which enabled him to move with difficulty the legs of frogs and to attract small scraps of paper would one day set in motion enormous railway trains. It will perhaps always be beyond our power to totally dissociate the atom, because the difficulties must increase as dissociation advances, but it would suffice if we could succeed in easily dissociating a small part of it. Whether the gramme of dissociated matter that we have supposed be taken from a ton of matter or even more, matters nothing. The result would always be the same from the point of view of the energy produced. The researches which I have essayed on these lines, and which will be set forth here, show that it is possible to largely hasten the dissociation of various substances.
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The methods of dissociation are, as we shall see, numerous. The most simple is the action of (light). It has further the advantage of costing nothing. In so fresh a field, with a new world opening out before us, none of our old theories should stop those who seek. "The secret of all who make discoveries," says Liebig," is that they look upon nothing as impossible." The results that could be obtained in this order of researches are truly immense. The power to dissociate matter freely would place at our disposal an infinite source of energy, and would render unnecessary the extraction of that coal whereof the provision is rapidly becoming exhausted. The scholar who discovers the way to liberate economically the forces which matter contains will almost instantaneously change the face of the world. If an unlimited supply of energy were gratuitously placed at the disposal of man he would no longer have to procure it at the cost of arduous labour. The poor would then be on a level with the rich, and there would be an end to all social questions.
The Evolution of Matter - the book The Evolution of Matter - Table of Contents