In 1858 Geissler developed the so-called Geissler tube or gas discharge tube. This is a glass tube filled with a rarefied gas and whose ends are provided with two electrodes, between which is a high electric voltage. While Geissler aimed his research at the light phenomena generated under these conditions, the gas discharge tube was soon used for other research too. The tube shown here, for example, could be used for research into discharge phenomena in gases at different densities and different electric voltages. However, all these phenomena were explained only after a theory about the structure of atoms had been developed in the early 20th century.
Gas discharge tube
1775 - 1799