  Forthcoming CMB experiments will allow us to accurately investigate the power
spectrum at very small scales ($\ell > 1000$). We predict the level of the
primary anisotropies, given the actual CMB measurements. The secondary
anisotropies generated after matter-radiation decoupling contribute additional
power in the tail of the CMB power spectrum. Together with the primary
anisotropies, we compute the predicted power spectra for three dominant
secondary effects induced by photon scattering. We predict these secondary
contributions in flat cosmological models for parameters in agreement (to
$2\sigma$) with the values allowed by current parameter estimates.
