The isotope shifts in the 283.3-nm resonance line of natural lead were measured by atomic-beam absorption spectroscopy with a 9.1-m focal-length spectrometer. The spectrum was calibrated internally by the measured 6<i>p</i>7<i>s</i><sup>3</sup><i>P</i>°<sub>1</sub> hfs separation of <sup>207</sup>Pb [J.-L. Cojan and H. R. Saussereau, C. R. Acad. Sci. Ser. B 277, 415 (1973)] and by the value calculated from the level-crossing results of Saloman and Happer [Phys. Rev. 144, 7 (1966)] and <i>gj</i> of Rudi-Saussereau <i>et al.</i> [Opt. Commun. 9, 186 (1973)]. The isotope shifts relative to <sup>208</sup>Pb are -46.6(6), <sup>207</sup>Pb center of gravity; -74.5(6), <sup>206</sup>Pb; -142(3), <sup>204</sup>Pb. The values are in units of 0.001 cm<sup>-1</sup>, the negative sign indicating a shift to lower wave numbers. The precision is nearly 1 order of magnitude greater than that of previous measurements.
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