Balmer, Johann Jakob (1825-1898), Swiss mathematician and physicist, born in Lausanne, Switzerland. In 1885 Balmer discovered a simple mathematical formula that generated the wavelength values for a certain series of spectral lines of the element hydrogen. This series of spectral lines is now called the Balmer series. The reason that Balmer's formula generated the correct wavelength values was not understood until the development of quantum theory in the early 1900s.