  Substitution of nickel by copper in the heavy fermion system
CeNi$_{9-x}$Cu$_x$Ge$_4$ alters the local crystal field environment of the
Ce$^{3+}$-ions. This leads to a quantum phase transition near $x\approx0.4$,
which is not only driven by the competition between Kondo effect and RKKY
interaction, but also by a reduction of an effectively fourfold to a twofold
degenerate crystal field ground state. To study the consequences of a changing
crystal field in CeNi$_8$CuGe$_4$ on its Kondo properties, inelastic neutron
scattering (INS) experiments were performed. Two well-defined crystal field
transitions were observed in the energy-loss spectra at 4 K. The crystal field
level scheme determined by neutron spectroscopy is compared with results from
specific heat measurements.
