Neutral Metal Atoms Research Articles

Experiments Bearing upon the Origin of Spectra

IN connection with Prof. Strutt's letter under the above title in NATURE of March 12, it may be of interest to direct attention to some previous work of Prof. Lenard's which contains results bearing on the same subject. Lenard (Annalen der Physik, vol. xvii., 1905, p. 197), as a result of a study of the light emission of the electric arc and the Bunsen flame containing metallic salts, showed that the principal and subordinate series are emitted by different distinct regions of the luminous source, and are thus due to different centres of emission. Further, he demonstrated that the centres emitting the different series behave differently in an electric field, and came to the conclusion that while the centres which emit the principal series are neutral metallic atoms (as has been also contended by Wien for the canal rays), the centres of the subordinate series are atoms rendered positive by the loss of one or more electrons, one for the first series, two for the second, and so on. This theory is strikingly borne out by Prof. Strutt's experiments, all of which seem to be explicable by it; in any case, this independent confirmation seems to place beyond doubt the different electrical state of the centres emitting the different series.