Return to Physics of the Ether
83. The Dynamic Effects of the Ether. — We will now turn to the consideration of the dynamic effects of the ether, and we may take the well-known case of the formation of water, by the combination of the mixed gases oxygen and hydrogen, as this case serves as a type of chemical processes, and, indeed, serves as an illustration of the process involved at the interchange of motion between the ether and the molecules of matter generally; the variety in the effects consisting in differences in the energy of action in the case of molecules of different vibrating periods, the variety in the effects depending also on the greater or less number of molecules which are in the act of combination at the same time. Thus the slow rusting of an iron wire, and the burning of a similar wire in oxygen gas with the scintillation of sparks, serve to represent two cases where the differences merely depend on the differences in the number of molecules which are in the act of combination at the same time, each separate molecule in the rusting of the wire entering into combination with the same velocity or intensity as each separate molecule of the wire when burnt, only in the former case the number of molecules in the act of combination at once is not sufficient to disturb the ether enough for the waves to be capable of affecting the eye.
84. If we regard a mixture of the gases oxygen and hydrogen, then before the match is applied the vibrating molecules are in free translatory motion, exchanging motion among themselves; any pair of molecules at their approach throwing the ether into forcible stationary vibration, and not coming into sufficient
proximity to unite. In order for the molecules to combine, they must, by the action of some force, be driven together beyond the outer neutral point of unstable equilibrium, which, as before set forth, separates the combined from the gaseous state. Although the force required to effect this is small compared with the energy with which the molecules are urged together after the neutral point is passed, it is nevertheless sufficient to prevent the spontaneous combination of the molecules. When, however, any means whatever, capable of forcibly disturbing the molecules, is resorted to, such as the application of a substance in intense molecular vibration, as, for example, an incandescent solid, a flame, &c, or even perhaps a sudden forcible concussion, indeed anything which suffices to drive a few of the molecules into proper proximity; when this is effected, the rarefaction produced in the intervening ether column thrown into forcible oscillation by any two approximated molecules, comes into effect, and the normal ether pressure on the remote halves of the pair of molecules being thereby brought into action, the molecules are driven forcibly together, they approach the internal neutral point of stable equilibrium, and are carried beyond it by their momentum, but rebound again, the molecules oscillating about this point as a position of stable equilibrium. Each pair of molecules during combination being driven at a high speed against the oscillating ether column intercepted between the approaching molecules, the oscillations of the column are thereby greatly intensified, and, therefore, those of the molecules which vibrate in synchronism with column, this giving rise to the ether waves of heat and light observed at the combination of the gases. At the same time the high intensification of the vibrating energy after combination has, by the stationary vibrations suddenly set up in the intervening ether, the effect of driving apart in all directions the molecules of water vapour, a general translatory motion (the motion characteristic of gaseous matter) being thus set up, the whole vaporous mass tending forcibly to expand in all directions, and producing the effect known as the * explosion/' It is of course clear that the combination of a few molecules, in the first instance, by the application of a flame, has the effect, by the molecular disturbance thus set up, of causing the practically instantaneous combination of the entire gaseous mass.
During the process of combination, the ether particles by whose action the molecules are driven towards each other, lose thereby a certain portion of their normal velocity; the amount of motion lost by the ether during the process being precisely that transferred to the molecules. This loss of motion sustained by the ether next the molecules commences to be replenished from the very commencement of the movement of the molecules, the ether particles simply continuing to exchange velocities (their normal mode of motion), and thus the spherical wave representing
the loss of motion is automatically carried off at the velocity of the particles themselves, or with the speed of a ware of light, so that the ether particles next the molecules are prepared for a fresh effort even before the gaseous molecules have had time fully to approach each other. If it were not for this high normal velocity of the ether particles, a sustained effort of a high intensity would be impossible to the ether, for only on this condition could fresh motion be drawn with adequate speed from the stores of motion contained in the ether at a distance. Moreover, only on this condition could the loss of motion sustained by the ether be, during the short time of the explosion, subdivided or distributed over a vast radial volume of the ether, whereby the local disturbance of the equilibrium of the ether is reduced to a minimum. The spherical wave representing the loss of motion sustained is carried off with extreme rapidity, and soon, from the vast number of ether par- ticles encountered which increases as the square of the distance, the loss of motion becomes so subdivided that, although existing as a whole, it soon practically ceases to exist as regards each particle taken separately.
85. Prom the known mechanical value of the process of combination of the gases oxygen and hydrogen, it may be computed that if the entire energy given up by tne ether were expended solely in developing the translatory motion of approach of the molecules in the process of combination, the maximum velocity imparted to the hydrogen molecule would amount to about nine miles per second; but since it is necessary to conclude that the translatory motion of approach of the molecule from the instant of its generation commences to be converted into vibratory motion (heat), it would follow that the full value of the translatory motion cannot be attained, although the inference appears warranted that a considerable part of the full value is attained; for, firstly, since the intensity of the vibratory motion (heat) depends on the velocity with which the molecule is urged against the oscillating ether column, the observed intensity of the heat therefore indicates that a high velocity of- translation must have been attained by the molecule; and secondly, the inference is necessary that the most intense development of vibratory motion (heat) takes place on the shortening of the ether column at the approach of the molecules, the vibrations of the column (due to the rapid forward and back- ward reflection of the. pulses attendant on its reduced length) being then intensified most forcibly; and, therefore, by reaction the vibrations of the molecules, the molecule then also having acquired its greatest velocity, and having reached the inner neutral point where the work of the ether ends, the molecule being driven by its momentum against the oscillating ether column from which it finally rebounds, and coming to the end of its path by converting its translatory motion into vibratory motion (heat). From these considerations, therefore, it would follow that the
greatest development of heat takes place, not during the development of the translatory motion, but afterwards, the translatory motion being first developed in great part, and then converted into heat, so that from this the inference would be warranted that the full mechanical value for the translatory motion is nearly attained.
The combination of the mixed gases oxygen and hydrogen being one of the most intense examples of chemical action known, and the mass of the hydrogen molecule being exceptionally small, it would follow that the velocity of the hydrogen molecule in this case must constitute one of the highest instances of molecular velocity developed in chemical action. However, even if the full value of the velocity (nine miles per second) were attained, this velocity constitutes but a small fraction of the normal velocity of the ether particles (that of a wave of light), so that it becomes apparent that the ether is an agent mechanically well adapted to follow up and to effect with ease the rapid movements of the molecules of matter even in the most intense instances of chemical action, as in the case of explosives, rapid combustion, &c.; or, in other words, the ether is, from the high normal velocity of its particles, an agent physically adapted to effect those extremely rapid changes in the positions of equilibrium of molecules, exhibited in the general phenomena of chemical action.
If, on the other hand, the ether particles did not possess a high normal velocity, or if by the same amount of enclosed energy the mass of the particles were greater and the speed less, then the production of the same velocity of motion in the molecules of matter could not take place without the loss of a considerable percentage of their absolute velocity by the ether particles, which would be attended by a palpable rarefaction or disturbance of the equilibrium of pressure of the ether; for it is important to observe that not only can a given decrement of velocity be sustained by the particles with a less disturbance, as the absolute velocity of the particles is greater, but* also the disturbance is less from a second cause when the absolute velocity of the particles is greater; for the speed with which the wave representing the loss of motion is carried off, and consequently the volume of the ether over which the loss of motion is subdivided, depends on the absolute normal velocity of the particles, the disturbance being less in proportion as the number of particles over which the loss of motion is subdivided is greater. Hence a high normal velocity of the particles of the agent contributes from two separate causes to reduce the disturbance of the equilibrium of the agent attendant on the production of a given dynamic effect. The existence of a high normal velocity for the ether particles is therefore the essential mechanical condition to render the ether adapted as a motive agent in an intense and long- continued development of motion, as exhibited in the intense molecular motion of rapid combustion, &c. On account of the
high absolute normal velocity of the ether particles, the proportionate loss of velocity sustained by the particles even in the most intense instances of chemical action, such as the explosion of gun-powder, for example, is not sufficient to produce a palpable disturbance of the equilibrium of the ether, and the loss of motion is rendered imperceptible by rapid distribution over a vast volume of the ether.