While Thomson was experimenting with his cathode ray tubes and Millikan with his oil drop experiment, discoveries were taking place in physics that would change the way that scientists would think about the material world. Most of those discoveries concerned the nature of light.
In 1885 Johannes Balmer (a Swiss schoolteacher of mathematics) was observing a phenomenon of the splitting of the light from a hydrogen gas tube into various "lines" when passed through a prism.
Balmer, who was superstitious about numbers, developed a formula that would reproduce the spacing between the lines. This formula was later refined by a Swedish physicist named Rydberg to give the frequency of each line (or the wavelength).
BUT WHY DOES HYDROGEN DO THIS, AND WHAT ARE FREQUENCY AND WAVELENGTH????????