Geissler-Tube

Johann Heinrich Wilhelm Geißler (1814-1879) was a German glassblower and physicist. 1857 he made a hand-crank mercury pump, and glass tubes that could contain a superior vacuum. In 1868 Geissler was awarded a honorary doctorate. The Geissler tube was used for entertainment throughout the 1800s. But around 1910 it evolved into commercial neon lighting. Advances in Plucker and Geissler's discharge tube technology developed into the Crookes tube. Crooks applied a much higher vacuum. With his device the electron was discovered in 1897. The later (1904 and 1906) the rectifying and amplifying vacuum tubes derived from the Crookes tubes. See also Crook tubes like the Maltese Cross and Paddlewheel.

Wikipedia: "It consists of a sealed, partially evacuated glass cylinder of various shapes with a metal electrode at each end, containing rarefied gasses such as neon, argon, or air; mercury vapor or other conductive fluids; or ionizable minerals or metals, such as sodium. When a high voltage is applied between the electrodes, an electrical current flows through the tube. The current dissociates electrons from the gas molecules, creating ions, and when the electrons recombine with the ions, the gas emits light by fluorescence. The color of light emitted is characteristic of the material within the tube, and many different colors and lighting effects can be achieved. The first gas-discharge lamps, Geissler tubes were novelty items, made in many artistic shapes and colors to demonstrate the new science of electricity. In the early 20th century, the technology was commercialized and evolved into neon lighting."

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