  Conductance histograms of work-hardened Al show a series up to 11 equidistant
peaks with a period of 1.15 +/- 0.02 of the quantum conductance unit G_0 =
2e^2/h. Assuming the peaks originate from atomic discreteness, this agrees with
the value of 1.16 G_0 per atom obtained in numerical calculations by Hasmy et
al.
