Over time, scientific instruments often enter the public arena, sometimes as common tools (like thermometers) or as devices providing entertainment (such as television). Today, we’ll look at an object perhaps unfamiliar in its original form but which has led to a wide variety of items that we encounter in our daily lives. The Museum recently purchased a group of 68 delicate Geissler tubes that will help us to tell the story of an important innovation.
A Geissler tube is a sealed glass cylinder, often spiraled or shaped to demonstrate an interesting property of physics. After the glass is blown, and an electrode attached to each end, the tube is evacuated of air, and typically filled with a gas, often argon, neon, or mercury vapor, or a metal that can be easily ionized, such as sodium. High voltage applied across the electrodes ionizes the gas or metal, releasing electrons. These electrons begin a sequence of events that ends with light emitted by atoms or molecules chosen specifically for their characteristic colors. By varying the shape and contents of the Geissler tube, or even nesting one inside another, you can create a wide variety of colors and exciting visual effects.
These tubes take their name from Heinrich Geissler (1814-1879), a physicist and highly skilled glass blower. He invented them in 1857, just two years prior to the development of spectroscopy. Geissler made precision instruments in Bonn, Germany in the 1850s, and enjoyed an international reputation after 1855. After Geissler’s death, various manufacturers produced these tubes until the middle of the 20th century.
Geissler tubes played an important role in physics and chemistry from the late 1850s until a century later. Scientists used them to explore and illustrate the complicated connections between electricity, magnetism, materials, and the ether, a fluid then thought to carry electrical and magnetic fields. These tubes also enabled the development of spectroscopy, the study of spectral lines emitted (or absorbed) by substances and a fundamental tool in physics, chemistry, and astronomy. Variations of these tubes led to the discovery of the electron, as well as the design of fluorescent and neon lighting, x-ray machines, and the cathode ray tube, which is at the heart of radar, TV tubes, the oscilloscope, and many other display devices.
From the 1880s, Geissler tubes were mass produced and on display to public audiences in Europe, demonstrating the wonders of electricity and conveying the power of science. Fascination with the color effects from the different gases and materials inside the tubes led directly to the commercially and culturally significant neon lighting industry after 1910. From the bright lights of Broadway to the glitter and glitz of Las Vegas and beyond, Geissler’s simple idea has now illuminated the world far beyond his lab.
Geissler tubes play an important role in the history of science, of the public demonstration of science, and of popular culture. Whether simply on display or actually lit up, these beautiful tubes can capture our imagination and fascinate us today just as they did a century ago. We are delighted to add these to the CMoG collection, and to include them in our plans for telling more of the story of the role of glass in science and technology.