London: Taylor and Francis, 1890. Three Quarter Leather. First Edition. vii, , 524 pp. 8vo. 10 plates, 8 folding. Rebound in an exquisite three quarter leather binding with brown leather spine with four raised bands, gold embossed titling on black leather patch titles, marbled paper insets to cover boards. Only indication of ex-library status is ink stamps on the title page. Very clean within. Fine.
Swedish physicist Johannes Rydberg (1854-1919) developed the first mathematical formula for the spectral lines of hydrogen atom (and other atoms or ions with only one electron). Rydberg’s insight came from using “wavenumber” (the inverse of the wavelength) in his calculations. He plotted the wavenumbers of the spectral lines against integers in different series and found that the resulting curves had similar shapes. Using this insight, he developed a function (called the “Rydberg formula”) to model these curves. This is the first publication in English of the Rydberg formula.