Recent calculations of the order (Z\alpha)^4(m/M)Ry pure recoil correction to
hydrogen energy levels are critically revised. The origins of errors made in
the previous works are elucidated. In the framework of a successive approach,
we obtain the new result for the correction to S levels. It amounts to -16.4
kHz in the ground state and -1.9 kHz in the 2S state.Comment: 15 pages, Latex, no figure