  A technique for measuring the electrical resistivity and absolute thermopower
is presented for pressures up to 30 GPa, temperatures down to 25 mK and
magnetic fields up to 10 T. With the examples of CeCu2Ge2 and CeCu2Si2 we focus
on the interplay of normal phase and superconducting properties. With
increasing pres- sure, the behaviour of CeCu2Ge2 evolves from that of an
antiferromagnetically ordered Kondo system to that characteristic of an
intermediate valence compound as the Kondo temperature increases by about two
orders of magnitude. In the pressure window 8-10 < P < 20 GPa, a
superconducting phase occurs which com- petes at low pressure with magnetic
ordering. For CeCu2Si2 the effective mass of carriers is probed by both the
coefficient of the Fermi liquid law and the ini- tial slope of the upper
critical field. The magnetic instability is studied no- tably for CeRu2Ge2 and
Yb-based compounds for which pressure-induced magnetic ordering tends to
develop. Finally, contrary to conventional wisdom, we argue that in heavy
fermions a large part of the residual resistivity is most likely not
independent of temperature; tentatively ascribed to Kondo hole, it can be very
pressure as well as sample dependent. [electrical resistivity, thermoelectric
power, heavy fermion, magnetic order, superconductivity]
