Johann Heinrich Wilhelm Geissler (1815-1879) was a German national who came from a glass-blowing family. About 1852 he became a maker of scientific instruments in Bonn, and in 1868 was awarded an honorary doctorate by the University of Bonn for his work at the university. In 1855 he constructed a vacuum pump that used droplets of mercury falling through a tube as a method of producing relatively high vacua. This pump was used to evacuate the discharge tubes that he made a few years later for Julius Pluecker. These tubes contained rarified gases, and the discharge was obtained in a narrow channel between the electrodes at either end of a straight tube. We still use discharge tubes in undergraduate laboratory work on spectra of gases. Note that this work required not only the technology of high vacuum, but also the technology of the high voltages obtained with the induction coil.

The set of Geissler tubes at the left shows some of the fanciful shapes in which Geissler tubes were made.     This display, mounted on a black velvet-covered board, is in the apparatus collection of Dartmouth College.

The Geissler tube at the right was at Oberlin College in Ohio when I photographed it about 1979. The tube is mounted on a base from another piece of electrostatic apparatus.

The Geissler tubes at the left are at Virginia Military Institute in Lexington, Virginia,     The discharge in the large tube takes place through narrow channels that are twisted into loops. The channels are surrounded by glass vessels containing liquids containing fluorescent dyes, such as fluorescin. The demonstration, done in a darkened room, is dazzling.

The upper Geissler tube is at Colby College in Maine, and the lower one is in the apparatus collection of Hampden-Sydney College in Virginia.     Geissler tubes are hard to date, but the examples on this page are probably no later than the nineteen twenties.

The anode of the Geissler tube at the left is made of aluminum cut to resemble leaves. The metal is coated with a fluorescent material that glows brightly in the dark when the tube is excited with a high voltage.    This unmarked piece of apparatus is in the apparatus collection of Franklin and Marshall College in Lancaster, Pennsylvania, and is probably ca. 1900.

   The Geissler tube below is mounted on a wood backet with a threaded connector in the middle of the bracket, suggesting that it was designed to be used with a rotating electric motor. It is in the apparatus collection of Hobart and William Smith Colleges in Geneva, New York.

This discharge tube with fluorescent rose leaves in the the collection of Richard J. Zitto.

The tubes to the right and left are in the demonstration rooms of the University of Texas in Austin. The University opened in 1890, which sets a lower bound on their age.     The tube at the right probably came from Queen & Co. of Philadelphia. The 1888 Queen catalogue notes that this tube contains "a rhomb of Iceland spar, giving a brilliant yellow light [when subjected to cathode rays], and a beautiful phosphorescence, lasting for perhaps a minute or more ... $10.00"

The set of three Geissler tubes at the right are in the Jack Judson Collection and are on display at the Magic Lanter Museum in San Antonio, Texas.

These four Geissler tubes are in the apparatus collection of Franklin and Marshall College in Lancaster, Pennsylvania. The tube directly below contains two types of fluorescent dyes that glow brightly when the discharge takes place. Return to Static Electricity Home Page  Return to Home Page

   The Geissler Tube below is in the collection of Hobart and William Smith Colleges in Geneva, New York. It was bought from Max Kohl of Chemnitz, Germany in the late 1920s. It can be pumped out while the high voltage is applied across the electrodes at the ends; a stopcock at the base allows it to be disconnected from the pump.

This pair of Geissler tubes shows the ability of cathode rays to excite fluorescent materials. The tube at the right has fluorscent minerals lying on the bottom, while the one at the right has a aluminum rose that is touched up with fluorescent paint,    The rose tube was made by Central Scientific, and the mineral tube is unmarked.    The tubes are in the apparatus collection at Hobart and William Smith Colleges in Geneva, New York

The two Geissler tubes at the right have uranium glass portions. The near example is an ordinary tube, while the farther one is designed to be pumped out -- its method of operation is not clear.    They are in the collection of Hobart and William Smith Colleges in Geneva, New York.

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