  The scaling of the magnetic field dependence of the remanent magnetization
for different temperatures and different spin-glass samples is studied.
Particular attention is paid to the effect of the de Almeida-Thouless (AT)
critical line on spin-glass dynamics. It is shown that results of the
mean-field theory of aging phenomena, with two additional experimentally
justified assumptions, predict $H/H_{AT}(T)$ scaling for remanent magnetization
curves. Experiments on a single crystal Cu:Mn 1.5 at % sample in the
temperature interval from $0.7T_{g}$ to $0.85T_{g}$ give results consistent
with this scaling. Magnetization vs. field curves for different Cu:Mn and
thiospinel samples also scale together. These experimental results support the
predictions of the mean-field theory of aging phenomena.
