Geissler is a well known figure in the history of scientific instruments since the descendants of his inventions – the Geissler tube and the mercuryvacuum pump are still in use today. The Geissler tube of 1855, in which gas at low pressure glowed when subjected to an electrical voltage, demonstrating the principle of the electric discharge lamp.
House where Geissler was born
Heinrich Geissler was born in the village of Igelshieb, in the Rennsteig area of the Dukedom of Saxony-Meiningen. His father Georg, was an innovative glass-blower and maker of instruments such as barometers andthermometers. Heinrich Geissler’s youth coincided with a flowering in interest in experimental natural sciences leading to a greater demand for laboratory apparatus, particularly hollow glassware, which was to catapult the craft of the glassblower from a cottage industry to a profession.
Geissler, however, earned his living for a decade as a traveling instrument maker before settling and establishing in 1854 a workshop in Bonn, a young university town with a demand for laboratory apparatus. Here Geissler worked closely with chemists, physicists, medical doctors, physiologists and mineralogists and built up an international client list. From 1855 he participated regularly in world exhibitions, winning several medals for his scientific apparatus.
In 1855 he devised his famous mercury air pump which later contributed to the success of Thomas Edison’s first incandescent lamps in 1879. Later, using an apparatus of his own invention, he was able to demonstrate, in collaboration with Julius Pluckers, that water reaches its maximum density at 3.8 C (later determined to be 3.98). Among his other inventions was also a vaporimeter.
Geissler began experimenting with what were later to become known as the ‘Geissler tube’ in 1857 and full-scale production of these was well underway in the 1880s.
An electrical discharge through a partially evacuated tube glows with a color depending on the type of glass in the tube and the gas inside. Studies of discharges in such tubes later led to the development of atomicphysics. These tubes, as modified by Sir William Crookes, become the first to produce cathode rays, leading eventually to the discovery of the electron (and a bit farther down the road to television).
Geissler tubes were (and still are) produced for demonstration purposes however in the early days they were more of a novelty item used in parlor tricks and post dinner entertainment. They are blown from delicate glass made into decorative shapes and range in size from just a few inches to several feet in some rare examples.
Some tubes are partly made from uranium glass that fluoresces a bright green color when the tube is electrified and some were blown with a hollow chamber surrounding the primary tube, this area filled with a colored liquid that produced even more vivid effects when the tubes are lit. Geissler’s tubes are the predecessors to the modern neon and fluorescent tubes.
Today Geissler tubes are highly sought after and are considered works of art showing off the glass artisan’s specialized skill. They are still produced today and are used for laboratory and school physics demonstrations to study electrons in motion.
Geissler tubes were constructed in many very creative shapes and sizes. It is not uncommon to find tubes with elaborate twisted swirls or colored water chambers. The tubes can be quite striking when activated. Below are some examples of the tubes dating from about 1868.
Take a look at these advertisements of Geissler tubes from the 1914 Catalog from Electro Importing Company of New York.
Geissler rotator motors (1868) were used in high voltage experiments with Geissler tubes. The activated tube was held in the clamp and rotated rapidly by the motor, creating beautiful patterns.
Geissler rotator motors
A “Voltana” Wimshurst machine (1921) was used to charge Geissler tubes.
Geissler recieved a honorary doctorate in 1868 from the Bonn University. He died on January 24, 1879, and is buried in Bonn.