On the basis of Lorentz's theory, if we limit ourselves to a single spectral line, it suffices to assume that each atom (or molecule) contains a single moving electron.
Pieter ZeemanMoreover, photography has made it possible to fix these images and now provides us with a permanent record of each observed spectrum, which can be measured out at any time.
Pieter ZeemanI count myself fortunate to be able to contribute to this work; and the great interest which the Royal Swedish Academy of Sciences has shown in my work and the recognition that it has paid to my past successes, convince me that I am not on the wrong track.
Pieter ZeemanThe rotation of the polarization plane is extraordinarily small in all gases, thus also in sodium vapour.
Pieter Zeeman