On the Quantum Theory of Line-Spectra. Part II, On the Hydrogen Spectrum. - [AUTHOR'S OFFPRINT - PRESENTATION-COPY]

1918. Copenhagen, Bianco Lunos, 1918. 4to. Original printed wrappers. Lower right corner of front wrapper bent. Small closed tear to front wrapper. Spine strip renewed. Otherwise fine and clean throughtout. First printing of the second part of Bohr's seminal work "On the Quantum Theory of the Line-Spectra" (which appeared in three parts and which was never finished), author's off-print (with "Separate copy" printed on front wrapper), presentation-copy, inscribed by Bohr: "Hr. Professor K. Prytz / med venlig Hilsen / fra Forfatteren"."By 1918 Bohr had visualized, at least in outline, the whole theory of atomic phenomena. ... He of course realized that he was still very far from a logically consistent framework wide enough to incorporate both the quantum postulates and those aspects of classical mechanics and electrodynamics that seemed to retain some validity. Nevertheless, he at once started writing up a synthetic exposition of his arguments and of all the evidence upon which they could have any bearing; in testing how well he could summarize what was known, he found occasion to check the soundness of his ideas and to improve their formulation. In the present case, however, he could hardly keep pace with the growth of the subject; the paper he had in mind at the beginning developed into a four-part treatise, 'On the Theory of Line Spectra', publication of which dragged over four years without being completed; the first three parts appeared between 1918 and 1922 [of which the second from 1918 is offered here], and the fourth, unfortunately, was never published. Thus, the full impact of Bohr's view remained confined to the small but brilliant circle of his disciples, who indeed managed better than their master to make them more widely known by the prompter publication of their own results" (D.S.B. 2: 246-47).The present second part deals with the hydrogen spectrum, whereas the first part dealt with the general theory, and the third with the spectra of elements of higher atomic structure. Peter Kristian Prytz (1851-1929), to whom the work is inscribed, was an important physicist of the generation before Bohr. He did immense work to better the conditions of the teaching of physics at the Polytechnic Institute in Copenhagen, where Bohr studied for many years and where he later became a teacher. Prytz introduced the teaching of experimental physics here and fought for more space, more apparatus, more money for teaching assistance and more time for teaching. Thus, he played a great role in the physics-environment in Copenhagen both during Bohr's years as a student and as a teacher.Most importantly, it was Prytz who (in 1907) attracted the necessary money for the institute which enabled him to create the physical laboratory that constituted the foundation of Danish experimental physics, the field of which Bohr became professor in 1916 (till 1920 - the years during which he was working on the "On the Quantum Theory of the Line Spectra").Rosenfeld, Bohr-Bibliography, 15.