 One of the most influential discussions of Bohr’s correspondence principle appears in Max Jammer’s 1966 book The Conceptual Development of Quantum Mechanics. Jammer takes the correspondence principle to be a relation between the kinematics of the electron and the properties of the emitted radiation. Like many interpreters of the correspondence principle, he focuses primarily on the frequency relation. He notes that Bohr also found an asymptotic correspondence between the intensities of the spectral lines and the amplitudes in the classical harmonic components, as well as a correspondence between the polarization of the emitted radiation and the character of the classical motion. Although Jammer notes these other correspondences, he seems to interpret the frequency correspondence as the primary correspondence principle. Regarding the status of this correspondence as a principle, Jammer writes,