and cannot be destroyed; so that if, as Thomson[1] suggested in 1867, the atoms of matter are constituted of vortex-rings in a perfect fluid, the conservation of matter may be immediately explained. The mutual interactions of atoms may be illustrated by the behaviour of smoke-rings, which after approaching each other closely are observed to rebound: and the spectroscopic properties of matter may be referred to the possession by vortex-rings of free periods of vibration.[2]
There are, however, objections to the hypothesis of vortex-atoms. It is not easy to understand how the large density of ponderable matter as compared with aether is to be explained; and further, the virtual inertia of a vortex-ring increases as its energy increases; whereas the inertia of a ponderable body is, so far as is known, unaffected by changes of temperature. It is, moreover, doubtful whether vortex-atoms would be stable. "It now seems to me certain," wrote W. Thomson[3] (Kelvin) in 1905, "that if any motion be given within a finite portion of an infinite incompressible liquid, originally at rest, its fate is necessarily dissipation to infinite distances with infinitely small velocities everywhere; while the total kinetic energy remains constant. After many years of failure to prove that the motion in the ordinary Helmholtz circular ring is stable, I came to the conclusion that it is essentially unstable, and that its fate must be to become dissipated as now described."
The vortex-atom hypothesis is not the only way in which the theory of vortex-motion has been applied to the construction of models of the aether, It was shown in 1880 by W. Thomson[4] that in certain circumstances a mass of fluid can exist in a state in which portions in rotational and irrotational
- ↑ Phil. Mag. xxxiv (1867), p. 10; Proc. R.S. Edinb. vi, p. 94.
- ↑ An attempt was made in 1883 by J. J. Thomson, Phil. Mag. xv (1883), p. 427, to explain the phenomena of the electric discharge through gases in terms of the theory of vortex-atoms. The electric field was supposed to consist in's distribution of velocity in the medium whose vortex-motion constituted the atoms of the gas; and Thomson considered the effect of this field on the dissociation and recoupling of vortex-rings.
- ↑ Proc. Roy. Soc. Edinb., xxv (1905), p. 565.
- ↑ Brit. Assoc. Rep., 1880, p. 473.
