Recently we reported on the differential resistance R(I) = dV/dI of na
rrow AuFe spin-glass wires (Phys. Rev. Let., 77 (1996) 2276). Surprisi
ngly, R(I) nas found to be asymmetric in I for the smallest samples. I
n this letter we present differential resistance measurements performe
d on a AuFe wire with a multiprobe geometry. The new experiments revea
l that the asymmetric behavior of R(I) can be explained in terms of a
mesoscopic thermoelectric effect. Our experiments also indicate that t
he thermopower S of a AuFe spin-glass alloy becomes size dependent for
length scales below a few hundred nanometers.