  We study the effect of box size on the matter power spectrum obtained via
cosmological N-body simulations. Within the framework of the cosmic screening
approach, we show that the relative deviation between the spectra for our
largest comoving box with L = 5632 Mpc/h and those for L = 280, 560, 1680,
4480, 5120 Mpc/h boxes consistently increases with decreasing box size in the
latter set in the redshift range $0\leq z\leq 80$ for the considered values. As
an additional demonstrative example, at redshift zero, we determine the values
$k_{1\%}$ corresponding to the modes at which relative deviations reach 1\%.
