Copenhagen: Jul. Gjellerups Forlag, 1922. 70 pages. Slim 8vo, original beige printed wrappers (very lightly worn but sturdy). Kobenhavn: Jul. Gjellerups Forlag, 1922. A very good(+) copy. Bohr wrote this work at the time that he and members of his laboratory staff were working on a theory of the periodic system of the elements. Bohr, by "the analysis of the evidence of the spectra, renewed the science of chemistry by putting at the chemists' disposal rational spectroscopic methods much more..... More