We have learnt through experience that when an electrical ray strikes the surface of an atom, an electron, and in some circumstances a second and even a third electron, can be detached.

Die elektrischen Quanten. Career
Stark worked in various positions at the Physics Institute of his alma mater until 1900 when he became an unsalaried lecturer at the University of Göttingen. (Sonderabdruck aus 'Annalen der Physik' 4.