  The propagation of electromagnetic surface waves guided by the planar
interface of two isotropic chiral materials, namely materials $\calA$ and
$\calB$, was investigated by numerically solving the associated canonical
boundary-value problem. Isotropic chiral material $\calB$ was modeled as a
homogenized composite material, arising from the homogenization of an isotropic
chiral component material and an isotropic achiral, nonmagnetic, component
material characterized by the relative permittivity $\eps_a^\calB$. Changes in
the nature of the surface waves were explored as the volume fraction
$f_a^\calB$ of the achiral component material varied. Surface waves are
supported only for certain ranges of $f_a^\calB$; within these ranges only one
surface wave, characterized by its relative wavenumber $q$, is supported at
each value of $f_a^\calB$. For $\mbox{Re} \lec \eps_a^\calB \ric > 0 $, as
$\left| \mbox{Im} \lec \eps_a^\calB \ric \right|$ increases surface waves are
supported for larger ranges of $f_a^\calB$ and $\left| \mbox{Im} \lec q \ric
\right|$ for these surface waves increases. For $\mbox{Re} \lec \eps_a^\calB
\ric < 0 $, as $ \mbox{Im} \lec \eps_a^\calB \ric $ increases the ranges of
$f_a^\calB$ that support surface-wave propagation are almost unchanged but $
\mbox{Im} \lec q \ric $ for these surface waves decreases. The surface waves
supported when $\mbox{Re} \lec \eps_a^\calB \ric < 0 $ may be regarded as akin
to surface-plasmon-polariton waves, but those supported for when $\mbox{Re}
\lec \eps_a^\calB \ric > 0 $ may not.
