Source : Webster's Revised Unabridged Dictionary (1913)

Vortex theory \Vortex theory\ (Chem. & Physics)
   The theory, advanced by Thomson (Lord Kelvin) on the basis of
   investigation by Helmholtz, that the atoms are vortically
   moving ring-shaped masses (or masses of other forms having a
   similar internal motion) of a homogeneous, incompressible,
   frictionless fluid. Various properties of such atoms (

   {vortex atoms}) can be mathematically deduced.