Proc. R. Soc. Lond . A 378, 445-460 (1981) The spectator electrons approximation in the 3d and 4s spectra of Cr I By J. P. Connerade, M. A. Baig and G. H. Newsom The paper by Connerade et al . (1981) reported measurements of 125 absorption structures due to single excitation of a 3d electron as well as of a series involving 27 double excitations, all of which lie above the first ionization limit and were previously unobserved. The subject of the paper is the validity of the spectator electrons approximation and is discussed in the light of Hartree-Fock calculations. The observations covered the range 1400-2000 Å and, in table 8, we also presented measurements for 19 members of the principal series of Cr I between 1990 and 1839 Å. It has recently been pointed out to us that measurements at higher dispersion than available to us had already been reported for the series in table 8 by Huber et al . (1975). This reference is listed in the N. B. S. bibliography (Hagan 1977) but is not quoted in the otherwise comprehensive references on Cr I by Sugar & Corliss (1977) and had, regrettably, been overlooked.