The Cathode Ray Tube site
History and Physics Instruments
The first discharge light
Johann Heinrich Wilhelm Geissler (1815-1879)
Born in Igelshieb, was a skilled glassblower from a glass art making family in Thuringen Germany and worked as a travelling instrument maker in Germany and the Netherlands. Geissler opened a small company in Bonn in 1852 to sell his self made scientific glass instruments to schools and Universities. In that same time he developed a mercury vacuum pump, with this instrument he was able to create an higher vacuum (2 Torr) than possible that time with standard equipment.
This new developed vacuum pump enabled the production of high vacuum tubes which led to many discoveries of new physics instruments like the different Crookes, Hittorf, Goldstein and X-ray tubes. Geissler experimented with different gasses in vacuum tubes, together with Julius Plücker who worked with him and named them Geissler tubes. When he applied high tension to the tubes they produced a bright luminous effect which was demonstrated for public in 1864 together with his new mercury vacuum pump.
This was the practical discovery of the first discharge light. Someting that was until then only possible in instruments like "electric eggs". The Geissler tubes where sold for demonstrations at Universities, schools and later on even for home-entertainment use. This was a rare phenomena in the time that there was only electric carbon and gas light. The glass tubes contain a low vacuum, the remaining gas molecules trapped in the tube together with a high voltage are responsible for a discharge.
Geissler solved the "metal electrode through glass problem" by using (expensive) platinum wire in a small lead glass seal which was melted into the soft sodalime glasswall of the tube. From the third quarter of the 19th Century until the 1930 Geissler tubes were produced by many glassblowers like Franz Müller (Geissler's Nachfolger), Greiner & Friedrichs, Rudolf Pressler and Richard Müller-Uri.
In France and and Britain also many scientific workshops started the production of these instruments. The tube makers often used uranium glass, fluorescent liquid and different types of rarified gas to make the most beautiful luminous compositions. The tubes where discharged by use of a Ruhmkorff coil or Wimshurst machine, this produced the high tension needed to light the tubes.
Geissler tubes are real pieces of art and are rare collectors items, the tubes are still made by some glassblowers in Germany.
The British Science Museum in London and the Dutch Teylers Museum in Haarlem displays original tubes from Heinrich Geissler.
In Thuringen a museum is dedicated to Geissler's work.
A biography of Heinrich Geissler can be found here.
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Uranium glass models
Another box with 6 French 14-16cm tubes ca1920
Nice set in an original cardboard box
late 1800 containing four 15cm tubes.
These early tubes never had end caps but only small platinum wire loops. Despite their age all four tubes are still working!
French box with 6 small 10cm Geissler tubes ca 1920
2 small 10cm early Geissler tubes with original box.
Sadly the vacuum is lost due to minor cracks between the sealing and the platinum connection wires. This is a common failure with this old tubes.
Two nice 25cm tubes on a stand.
Two double twist with Catherine wheel Geissler tubes.
The larger tube has the typical early wire connections in this case probably Dumet wire which came in use after 1911 and replaced the expensive platinum wire.
Dumet wire consisted of a 42% nickel -iron alloy coated with a thin layer of copper and is a bit thicker than the old Platinum wire.
For more info about Dumet wire look here.
14cm tube with press glass grape in the middle.
Another tiny 9cm Geissler tube
Large 30cm Geissler tube ca 1900
This tube has stratifications as can be seen on the left side. In the tube there are some white grains probably to restore the correct pressure for this effect.
Geissler tube with shell decoration
Fine early Geissler tube with uranium glass twist.
Geissler tube with two grape decorations
Collection of 3 small Geissler tubes with uranium glass.
Standing Geissler tube with uranium glass twist.
This is an extraordinary and rare 15cm Geissler tube with a face and bold head.
Small 11cm tube with turn.
Rare 15cm tube with interrupted wobble.
Nice old 20 cm Geissler tube with two uranium glass grapes.
Early small 10cm tube with wire loops The light between the three uranium glass bubbles has a stratification effect.
Didactic Geissler discharge tube.
This is a very early example from the late 1800's on a nice black painted wooden stand.
A very nice 25cm late 1800's Geissler tube.
The wobbles of this tube are made from rare blue fluorescent glass. Originally the tube used to have platinum wire connections, the caps are a later addition.
Click on the picture to see a larger version.
An early 18cm tube with interrupted uranium glass curl.
The electrodes are sealed with blue glass, late 1800.
Even at its age the vacuum is still perfect!
A late 1800's Geissler tube on a stem with rare blue fluorescent glass and uranium glass spheres and stratification discharge.
Originally the tube used to have platinum wire connections, the caps are a later addition.
This is a very cute little snake tube, length 15cm.
The same tube can be seen in a 1870 French catalogue. This tube has blue fluorescent glass which is typical for early French tubes.