C. T. R. Wilson, that charged particles can serve as nuclei for the

condensation of water-vapour, he was further able to determine the value of the electrical charge carried by these particles, which was found to be constant also, and equal to the charge carried by univalent ions, _e.g._, hydrogen, in electrolysis. Hence, it follows that the mass of these kathode particles must be much smaller than the hydrogen ion, the actual ratio being about 1 : 1700. The first theory put forward by Sir J. J. Thomson in explanation of these facts, was that these kathode particles (“corpuscles” as he termed them) were electrically charged portions of matter, much smaller than the smallest atom; and since the same sort of corpuscle is obtained whatever gas is contained in the vacuum tube, it is reasonable to conclude that the corpuscle is the common unit of all matter. Proof that the Electrons are not Matter. § =80.= This eminent physicist, however, had shown mathematically that a charged particle moving with a very high velocity (approaching that of light) would exhibit an appreciable increase in mass or inertia due to the charge, the magnitude of such inertia depending on the velocity of the particle. This was experimentally verified by Kaufmann, who determined the velocities, and the ratios between the electrical charge and the inertia, of various kathode particles and similar particles which are emitted by compounds of radium (see §§ 89 and 90). Sir J. J. Thomson calculated these values on the assumption that the inertia of such particles is entirely of electrical origin, and thereby obtained values in remarkable agreement with the experimental. There is, therefore, no reason for supposing the corpuscle to be matter at all; indeed, if it were, the above agreement would not be obtained. As Professor Jones says: “Since we know things only by their properties, and since all the properties of the corpuscle are accounted for by the electrical charge associated with it, why assume that the corpuscle contains anything but the electrical charge? It is obvious that there is no reason for doing so. “_The corpuscle is, then, nothing but a disembodied electrical charge_, containing nothing material, as we have been accustomed to use that term. It is electricity, and nothing but electricity. With this new conception a new term was introduced, and, now, instead of speaking of the corpuscle we speak of the _electron_.”[96] Applying this modification to the above view of the constitution of matter, we have what is called “the electronic theory,” namely, that the material atoms consist of electrons, or units of electricity in rapid motion; which amounts to this--that matter is simply an electrical phenomenon. [96] H. C. JONES: _The Electrical Nature of Matter and Radioactivity_ (1906), p. 21. The Electronic Theory of Matter. § =81.= Sir J. J. Thomson has elaborated this theory of the nature and constitution of matter; he has shown what systems of electrons would be stable, and has attempted to find therein the significance of Mendeléeff’s generalisation and the explanation of valency. There can be no doubt that there is a considerable element of truth in the electronic theory of matter; the one characteristic property of matter, _i.e._, inertia, can be accounted for electrically. The fundamental difficulty is that the electrons are units of negative electricity, whereas matter is electrically neutral. Several theories have been put forward to surmount this difficulty. Certainly the electron is a constituent of matter; but is it the sole constituent? Recent research indicates that, as already pointed out, all atoms consist of two distinct portions, a massive central nucleus, whose net charge is positive, surrounded by a number of electrons, just sufficient to neutralize this charge. The point of greatest interest is that the indicated number of free electrons is exactly the number which expresses the position of the element in the Periodic Table, reckoning helium as 2, lithium as 3, and so on; and it would seem that the chemical properties of the elements are determined entirely by these electrons, and are, therefore, not, strictly speaking, periodic functions of their atomic weights, as was formerly thought (§ 78), but of their atomic numbers. The exact nature of the nuclei of the various atoms has yet to be determined: in the case of the atoms heavier than helium they would appear to be made up of the nuclei of hydrogen and (or) helium atoms together with--in many cases--electrons insufficient in number to neutralize the positive charges associated with these. The Etheric Theory of Matter. § =82.= The analysis of matter has been carried a step further. A philosophical view of the Cosmos involves the assumption of an absolutely continuous and homogeneous medium filling all space, for an absolute vacuum is unthinkable, and if it were supposed that the stuff filling all space is of an atomic structure, the question arises, What occupies the interstices between its atoms? This ubiquitous medium is termed by the scientists of to-day “the Ether of Space.” Moreover, such a medium as the Ether is demanded by the phenomena of light. It appears, however, that the ether of space has another and a still more important function than the transmission of light: the idea that matter has its explanation therein has been developed by Sir Oliver Lodge. The evidence certainly points to the conclusion that matter is some sort of singularity in the ether, probably a stress centre. We have been too much accustomed to think of the ether as something excessively light and quite the reverse of massive or dense, in which it appears we have been wrong. Sir Oliver Lodge calculates that the density of the ether is far greater than that of the most dense forms of matter; not that matter is to be thought of as a rarefaction of the ether, for the ether within matter is as dense as that without. What we call matter, however, is not a continuous substance; it consists, rather, of a number of widely separated particles, whence its comparatively small density compared with the perfectly continuous ether. Further, if there is a difficulty in conceiving how a perfect fluid like the ether can give rise to a solid body possessed of such properties as rigidity, impenetrability and elasticity, we must remember that all these properties can be produced by means of motion. A jet of water moving with a sufficient velocity behaves like a rigid and impenetrable solid, whilst a revolving disc of paper exhibits elasticity and can act as a circular saw.[97] It appears, therefore, that the ancient doctrine of the alchemistic essence is fundamentally true after all, that out of the “One Thing” all material things have been produced by adaptation or modification; and, as we have already noticed (§ 60), there also appears to be some resemblance between the concept of the electron and that of the seed of gold, which seed, it should be borne in mind, was regarded by the alchemists as the common seed of all metals. [97] See Sir OLIVER LODGE, F.R.S.: _The Ether of Space_ (1909). Further Evidence of the Complexity of the Atoms. § =83.= There are also certain other facts which appear to demand such a modification of Dalton’s Atomic Theory as is found in the Electronic Theory. One of the characteristics of the chemical elements is that each one gives a spectrum peculiar to itself. The spectrum of an element must, therefore, be due to its atoms, which in some way are able, at a sufficiently high temperature, to act upon the ether so as to produce vibrations of definite and characteristic wave-length. Now, in many cases the number of lines of definite wave-length observed in such a spectrum is considerable, for example, hundreds of different lines have been observed in the arc-spectrum of iron. But it is incredible that an atom, if it were a simple unit, would give rise to such a number of different and definite vibrations, and the only reasonable conclusion is that the atoms must be complex in structure. We may here mention that spectroscopic examination of various heavenly bodies leads to the conclusion that there is some process of evolution at work building up complex elements from simpler ones, since the hottest nebulæ appear to consist of but a few simple elements, whilst cooler bodies exhibit a greater complexity. Views of Wald and Ostwald. § =84.= Such modifications of the atomic theory as those we have briefly discussed above, although profoundly modifying, and, indeed, controverting the philosophical significance of Dalton’s theory as originally formulated, leave its chemical significance practically unchanged. The atoms can be regarded no longer as the eternal, indissoluble gods of Nature that they were once supposed to be; thus, Materialism is deprived of what was thought to be its scientific basis.[98] But the science of Chemistry is unaffected thereby; the atoms are not the ultimate units out of which material things are built, but the atoms cannot be decomposed by purely chemical means; the “elements” are not truly elemental, but _they are chemical elements_. However, the atomic theory has been subjected to a far more searching criticism. Wald argues that substances obey the law of definite proportions because of the way in which they are prepared; chemists refuse, he says, to admit any substance as a definite chemical compound unless it does obey this law. Wald’s opinions have been supported by Professor Ostwald, who has attempted to deduce the other stoichiometric laws on these grounds without assuming any atomic hypothesis[99]; but these new ideas do not appear to have gained the approval of chemists in general. It is not to be supposed that chemists will give up without a struggle a mental tool of such great utility as Dalton’s theory, in spite of its defects, has proved itself to be. There does seem, however, to be logic in the arguments of Wald and Ostwald, but the trend of recent scientific theory and research does not appear to be in the direction of Wald’s views. Certainly, however, it appears that, on the one hand, the atomic theory is not necessitated by the so-called “stoichiometric laws”; but, on the other hand, a molecular constitution of matter seems to be demanded by the phenomenon known as the “Brownian Movement,” _i.e._, the spontaneous, irregular and apparently perpetual movement of microscopic portions of solid matter when immersed in a liquid medium; such movement appearing to be explicable only as the result of the motion of the molecules of which the liquid in question is built up.[100] [98] For a critical examination of Materialism, the reader is referred to the present writer’s _Matter, Spirit and the Cosmos_ (Rider, 1910), especially Chapters I. and IV. [99] W. OSTWALD: “Faraday Lecture,” _Journal of the Chemical Society_, vol. lxxxv. (1904), pp. 506 _et seq._ See also W. OSTWALD: _The Fundamental Principles of Chemistry_ (translated by H. W. Morse, 1909), especially Chapters VI., VII. and VIII. [100] For an account of this singular phenomenon, see Prof. JEAN PERRIN: _Brownian Movement and Molecular Reality_ (translated from the _Annales de Chimie et de Physique_, 8me Séries, September, 1909, by F. Soddy, M.A., F.R.S., 1910).