Roentgen X-Ray Tube

This is one of the first x-ray tubes used by physicist Wilhelm Conrad Roentgen (1845-1923), who discovered this new form of radiation at the University of Wurzburg in Germany, on November 8, 1895. While experimenting with cathode rays by passing an electric current through a glass vacuum tube covered with black paper, he noticed an unexpected green glow on a little screen covered with phosphorescent paint lying on his bench. He quickly realized that some mysterious invisible rays were leaving the tube, going through the black paper, and causing the screen to become luminous. These unknown, or "x" rays were shown to pass easily through wood, cloth, and paper, but not denser material. He showed that they could even pass through the skin and reveal the bones of the human hand. The medical diagnostic and therapeutic implications of the x-ray were realized quickly. X-ray imaging remains the most widely used form of body imaging today.
This tube was purchased from a private owner in Germany and presented to the Smithsonian Institution in 1956 by the General Electric Company's X-ray Department of Milwaukee, Wisc. It is part of a very large and rich radiology collection at NMAH.
Currently not on view
Object Name
x-ray tube
Date made
ca 1985
ca 1896
discovered x-rays
Roentgen, W. C.
Roentgen, W. C.
Physical Description
glass (overall material)
wood (overall material)
overall: 6 in x 7 in x 10 in; 15.24 cm x 17.78 cm x 25.4 cm
overall, case: 5 3/4 in x 10 1/4 in x 7 3/4 in; 14.605 cm x 26.035 cm x 19.685 cm
Place Made
Deutschland: Bayern, Würzburg
ID Number
catalog number
accession number
Health & Medicine
See more items in
Medicine and Science: Medicine
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
General Electric Company
Related Publication
Kendrick, Kathleen M. and Peter C. Liebhold. Smithsonian Treasures of American History

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Selected comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about the history, rarity, or value of your personal artifacts.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Enter the characters shown in the image.