770 
MR. J. LARMOR ON A DYNAMICAL THEORY OF 
i.e. of the absolute rotation in the sether, will be set in action in the surroundinor 
medium. If the metals are perfect conductors the effective flow of displacement will 
he confined to the surface, and will involve simply a vortex-sheet along the surface of 
each metal ; but if the conducting power is imperfect the disturbance will diffuse 
itself into the metals, and the final steady condition will be one in which it is 
uniformly distributed throughout them, forming an ordinary electric current obeying 
Oner’s law, 
68. On the present theory, high specific inductive power in a substance is equi¬ 
valent to low electric elasticity of the aether; it in fact stands to reason that an 
elastic medium whose continuity is broken by the inelastic and mobile portions which 
represent the cores of vortex-atoms may from this cause alone have its effective 
elasticity very considerably diminished. 
Moreover it has been ascertained that, in electrolytic liquids, the specific inductive 
capacity attains very great values; the aether in these media interposes a pro¬ 
portionally small resistance to rotation, and the mobility or some other property of 
the vortex-molecules in it has brought it so much the nearer to instability; it is thus 
the easier to see wh}^ such media break down under comparatively slight electric 
stress. Such a medium also frees itself, as described belowg from electric stress, 
without elastic rupture, in a time short compared with ordinary standards, but in 
most instances long compared with the periods of light-vibrations ; while in metallic 
media the period of decay of stress is at least of the same order of smallness as the 
periods of light-'waves. 
69. x4n atom, as above specified, would be mathematically a singular point inthe fluid 
medium of rotational elastic quality. Such a point may be a centre of fluid circula¬ 
tion, and may have elastic twist converging on it, but it cannot have any other special 
property besides these ; in other words this conception of an atom is not an additional 
assumption, but is the unique conception that is necessarily involved in the hypothesis 
of a simple rotationally elastic sether. 
The attraction of a positively-charged atom for a negatively-charged one, according 
to the law of inverse squares, has already been elucidated. If the two atoms are 
moved towards each other so slowly that no kinetic energy of the medium is thereby 
generated, the potential energy of the rotational strain between them is diminished ; 
and this diminution can be accounted for, in the absence of dissipation, only by 
mechanical work performed by the atoms or stored up in them in their approach. It 
has been observed by von Helmholtz that the phenomena of reversible polarization 
in voltameters involve no sensible consumption of energy, but that it is the actions 
which eftect the transformation of the electrically charged ions into the electrically 
neutral molecules that demand the expenditure of motive power; and he draws the 
conclusion that energy of chemical decomposition is chiefly of electrical origin. In 
the explanation liere outlined, the chemical (hydrodynamic) forces between the 
component atoms of the molecule are required to be, in the equilibrium position, of 
