An Attempt Towards A Chemical Conception Of The Aether
If the Newtonian theory of gravity revealed the existence of forces acting at infinitely great distances, the chemistry of Lavoisier, Dalton and Avogadro Gerhardt, on the other hand, disclosed the existence of forces of immense power acting at infinitely small distances, and transmutable into all other forms of energy, mechanical and physical. Thus all the present-day fundamental conceptions of natural science — and consequently the conception of the ether — must necessarily be considered under the combined influence of chemical, physical, and mechanical teachings. Although skeptical indifference is prone to discern only a ‘working hypothesis’ in the conception of the ether, yet the earnest investigator, seeking the reality of truth, and not the image of fantasy, is forced to ask himself what is the chemical nature of the ether.
Before endeavoring to give an answer respecting the chemical nature of ether, I think it necessary to state my opinion regarding the belief held by some in the unity of the substance of the chemical elements and their origin from one primary form of matter. According to this view, ether consists of this primary matter in an unassociated form, that is, not in the form of the elementary atoms or molecules of substances, but as the constituent principle out of which the chemical atoms are formed.
This view has much that is attractive. The atoms are regarded as proceeding from primary matter in the same way as celestial bodies are sometimes represented as being formed from disunited bodies, such as cosmic dust, etc. The celestial bodies so formed remain surrounded by the cosmic dust, etc., from which they took their origin. So also the atoms remain in the midst of the all-pervading and primary ether from which they took their origin. Some persons assume also that atoms can be split up into their dust or primary matter, just as comets break up into falling stars; and that, as the geological changes of the earth or the building up and dissociation of heavenly bodies proceed before our eyes, so also do the atoms break up and form again in the silence of their eternal evolution.
Others, without denying the possibility of such a process in the exceptional rare cases, consider the world of atoms to have been established once for all, and do not admit the possibility of decomposing the atom into its primary matter, or of forming new atoms of any chemical element from this primary matter by experimental means. In a word, they regard the process of the creation of atoms as finite and not subject to repetition, while they consider the ether as the residue remaining after the formation of atoms.
This view need not be considered here, it being solely the fruit of imagination and unproved by any experimental investigation. But the former theory of a progressive evolution of the substance of atoms cannot be passed unnoticed by chemistry, for fundamental principles of this science are the indestructibility of matter and the immutability of the atoms forming the elements. If ether were producible fro atoms and atoms could be built up from ether, the formation of new unlooked-for atoms and the disappearance of portions of the elements during experiment would be possible.
A belief in such a possibility has long been held in the minds of may by force of superstition; and the more recent researches of Emmens to convert silver into gold, and those of Fittica (1900) to prove that phosphorus can be converted into arsenic, show that it yet exists. In the 50 years during which I have carefully followed the records of chemistry, I have met with many such instances, but they have always proved unfounded. It is not my purpose here to defend the independent individuality of the chemical elements, but I am forced to refer to it in speaking of the ether, for it seems to me that, besides being chemically invalid, it is impossible to conceive of an ether as a primary substance, because such a substance should have some mass or weight and also chemical relations — mass in order to explain the majority of phenomena proceeding at all distances up to the infinitely great, and chemical relations in order to explain those proceeding at distances infinitely small or commensurable with the atoms.
If the question were restricted to the ether which fills space and serves as a medium for the transmission of energy, it would in a way be possible to limit oneself to the supposition of mass without reference to its chemical relations and even to consider the ether as a primary matter, Justas the mass of a planet may be conceived without regarding its chemical composition. But such an indifferent, indefinite ether loses all sense of reality and awakens the misgivings of the earnest investigator, directly he realizes that it must permeate all substances. The necessity I an easy and perfect permeation of all bodies by the ether has to be admitted, not only for the comprehension of many physical phenomena (such as those o optics), but also owing to the great elasticity and rarity of the ethereal substance, the atoms of which are always conceived a being far more minute than the atoms and molecules of the known chemical substances.
Moreover, this permeability of ether I all bodies explains why it cannot be isolated from substances, which indeed behave in respect to ether like a sieve to water or air. The capacity of the ether to penetrate all substances may, however, be regarded as the ideal of the diffusion of gases through metals and other diaphragms. Hydrogen, which ha a small atomic weight and is the lightest of all known gases, not only diffuses more rapidly than any other gas, but also has the faculty of penetrating through walls of such metals as platinum and palladium, which are impervious to other gases.
This property is due, not only to the rapidity of motion of the molecules of hydrogen, closely connected with its small density, but also to a chemical faculty of the same kind as exhibited in the formation of metallic hydrides, of solutions, alloys and other indefinite compounds. The mechanism of this penetration may be likened (at the surface of the body penetrated) to the solution of a gas in a liquid, that is, to the gaseous particles leaping into the interstices between the particles of the liquid with a retardation of their motion (a partial liquefaction of the gas) and a bringing into harmony of the motion of both kinds of particles. The condensed gas absorbed at the surface of contact travels in all directions through the body, and diffuses from one layer to another until it entirely permeates it.
The possibility of gaseous hydrogen acting thus is evident from the fact that even gold diffuses through solid lead under the same force. At length, at the opposite surface of the body penetrated, the condensed gas will find it possible to escape into greater freedom, and will continue to pass in this direction until its degree of concentration becomes the same on both sides. When this takes place it does not set up a sate of rest, but one of mobile equilibrium, that is, equal numbers of molecules or atoms will escape and leap in at both sides. If, as it must, ether has the faculty of permeating all substances, it must be even lighter and more elastic (greater vis viva) than hydrogen, and, what is most important, must have less capacity than hydrogen to form chemical compounds with the bodies it permeates.
Compounds are characterized by the fact that the diverse atoms in them form systems or molecules, in which the different elements are in compatible, harmonious motion. We must therefore suppose that such a state of harmonious motion of, for instance, hydrogen and palladium, is actually set up in those atoms of hydrogen which permeate the palladium, and that in so doing it forms with the palladium some compound (either Pd2H or another) which easily dissociates when heated. Hence it seems to me that the atoms of ether are so void of this faculty of forming compounds (which is already weak in hydrogen) that such compounds dissociate at all temperatures, and that therefore nothing beyond a certain condensation among the atoms of substances can be looked for in the ether.
Eight years ago, it would have been most arbitrary to deny the existence, in the substance or atoms of ether, of the faculty of forming any compounds with their chemical elements, for in those days all the known elements were, directly or indirectly, capable of entering into mutual combination. But in 1894 Lord Rayleigh and Professor Ramsay discovered argon, and defined it as the most inactive element; this was followed by the discovery of helium, the existence of which Lockyer had predicted by its spectrum as a solar element, and subsequently by the separation of neon, krypton and xenon from air.
None of these five new gases have yet given any definite compounds, although they clearly evince the faculty of solution, i.e., of forming definite, easily dissociated compounds. Thus we have now every right to say that the ether is unable to form any stable compounds with other chemical atoms, although it permeates all substances.
Hence the ether may be said to be a gas, like helium or argon, incapable of chemical combination. This definition of the ether as a gas, signifies that it belongs to the category of the ordinary physical states of matter, gaseous, liquid or solid. It does not require the recognition of a peculiar fourth state beyond the human understanding (Crookes). All mystical, spiritual ideas about ether disappear. In calling ether a gas, we understand a ‘fluid’ in the widest sense; an elastic fluid having no cohesion between its parts. Furthermore, if ether be a gas, it has weight; this is undisputable, unless the whole essence of natural science, from the days of Galileo, Newton, and Lavoisier, be discarded for its sake.
But since ether possesses so great a penetrative power that it passes through every envelope, it is, of course, impossible to experimentally determine its mass in a given amount o other substances, or the weight of a given volume of ether. We ought, therefore, not to speak of the imponderability of ether, but only of the impossibility of weighing it.
The preceding remarks are in exact accordance with the generally accepted conception of ether. The only addition made is to ascribe to ether the properties of a gas, like argon and helium utterly incapable of entering into true chemical combination. This point lies at the basis of our investigation into the chemical nature of ether, and includes the following two fundamental propositions:
(1), that the ether is the lightest (in this respect ultimate) gas, and is endowed with a high penetrating power, which signifies that its particles have, relatively to other gases, small weight and extremely high velocity, and
(2), that ether is a simple body (element) incapable of entering into combination or reaction with other elements or compounds, although capable of penetrating their substance, just as helium, argon, and their analogues are soluble in water and other liquids.
The argon group of gases and the periodic system o the elements have such a close bearing upon our further consideration of the chemical nature of ether that it behooves us to look at them more closely.
When in 1869 I first showed the periodic dependence of the properties of the elements upon their atomic weights, no element incapable of forming definite compounds was known, nor was the existence of such an element even suspected.
Therefore the periodic system was arranged by me in groups, series, and periods, starting with group I and series I, with hydrogen as the lightest and least dense of all the elements. It never occurred to me that hydrogen might be the starting point of a system of elements. Guided by this system, I was able to predict both the existence of several unknown elements and also their physical and chemical properties in a free and combined state.
These elements, gallium, scandium, and germanium, were subsequently discovered by Lecoq de Boisbaudran, Nilson, and Winkler respectively. I made these predictions by following what is known in mathematics as a method of interpolation, that is, by finding intermediate points by means of two extreme points whose relative position is known. The fact of my predictions having proved true confirmed the periodic system of elements, which may now be considered as an absolute law.