Abstract
A modified King electric furnace, charged with rare earth salts, has been used to observe the absorption spectra of cerium, neodymium and samarium in the region 12,000A to 2500A with a 21-ft. concave grating giving dispersion of 2.5A/mm in the first order. The observations include 600 lines in cerium, 450 in neodymium, and 1500 in samarium. In general the absorption data confirm the line types as given by King's temperature classification in that, of those lines which are absorbed, the class I lines are more strongly absorbed than class II lines, which are in turn stronger than class III lines, and provide additional data in that only those lines of each class which involve the lowest levels appear in absorption.

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