Mutually Supporting Evidence in Atomic Spectra

Atomic emission spectra were observed in the nineteenth century and early twentieth century to be grouped into distinct series. By means of the Ritz combination principle, evidence of the structure of some series supports the structure of others, and vice versa, forming many relations of mutual support. The Ritz combination principle itself initially supplied evidential support for the nascent quantum theory. Soon the more developed quantum theory provided support for a corrected version of the Ritz combination principle.