Geissler tube is a gaseous-discharge tube similar to a neon lamp. It consists of a glass tube containing such gases as hydrogen, nitrogen, oxygen, and air under low pressure. The gases are made to glow with brilliant colors by passing an electric current through the tube. Scientists use Geissler tubes in research, particularly to examine incandescent gases with a device called a spectrometer (see Spectrometer ). The tubes were first built by Heinrich Geissler, a German instrument maker, in the late 1850’s.
Geissler tubes vary in shape. An electrode is sealed into each end of the tubes. Most Geissler tubes have electrodes made of platinum wire. The electrodes are connected to the opposite poles of an electrostatic machine or an induction coil. These devices create an electric current, which passes from one electrode to the other. The current causes the gases in the tube to produce different colors of light.
