Return to Physics of the Ether
90. We have referred to the decrement, or loss of motion, sustained by the ether particles in developing motion in the molecules of matter (in chemical action, &c.) as a "wave." Now, since the term "wave" in general applies to regular or periodic increments and decrements of velocity experienced by the component particles of an aeriform medium, the periodic character of such waves enabling them to accumulate motion, so as to be capable in certain cases of affecting the senses (as in the phenomena of light and sound); it is well, therefore, to distinguish the true character of the wave representing the loss of motion sustained by the ether in the production of any movement or dynamic effect. Although it is necessary to conclude that in the performance of work by the ether, as in the case of combustion, for example, a separate wave, representing the equivalent loss of motion sustained by the ether, must be produced at the approach (combination) of each separate pair of molecules; still this could not be regarded as a "wave" in the ordinary sense, since this form of wave represents only a decrement of motion, and not an equal increment and decrement, of which a "wave" consists in the general meaning of the term. Moreover, these decrements of motion sustained by the ether as the motive agent in the movement of approach of the molecules, do not in any way follow in regular or periodic succession as in the case of "waves commonly so termed, and by which they are enabled to affect the senses, but
these waves or decrements of motion are superimposed upon each other, and the distinctive character of each wave (i. e. the wave attendant on the approach of each separate pair of molecules) is lost, or the waves are necessarily merged into each other, which would tend to produce simply an appreciably uniform loss of motion in the ether around, spread over a vast concentric volume of the ether, the loss of motion being proportionally very small as regards each ether particle taken separately, the loss diminishing uniformly as the square of the distance from the origin. If we regard an isolated wave, or the decrement of motion developed in the ether at the combination of a single pair of molecules, then this wave being due to the translatory movement of approach of the entire mass of the molecule, would be of disproportionately greater length than the rapid and periodic waves of neat simultaneously generated due to the vibrations of the molecule during its approach, these short waves of heat being, therefore, super* imposed upon the wave representing the decrement of motion : the short waves (waves of heat and light) being also capable, from their periodic character, of appealing to the senses.
So in a somewhat analogous manner the wave or decrement of motion developed in the air, at the mutual approach of two vibrating suspended tuning-forks, and which represents the loss of motion sustained by the molecules of air in urging the forks together, must be of much greater length than the periodic waves due to the rapid vibrations of the forks during their approach, these short waves being superimposed upon the wave representing the decrement of motion. The disproportionately greater length of the wave representing the decrement of motion will become apparent when it is considered that if the approach of the forks lasted but one second, the loss of motion would in that time be spread over a spherical mass of air of more than a thousand feet radius, or the loss of motion is so subdivided as to be totally incapable of appealing to the senses in any way, while, on the other hand, the periodic character of the waves aae to the vibrations of the forks (the waves of sound) enables these waves to affect the senses.