96 X-Rays
Other scientists theorized that rays would be emitted from a Crookes’ tube and had
named them cathode rays after the name of one of the metal plates inside the tube. Crookes
thought these rays might come from another world. But no one had detected, measured, or
studied these unknown rays.
Roentgen suspected that cathode rays had somehow exposed his film. Two weeks later
he was able to prove the existence of these mysterious rays, which he named “X-rays” since
“X” was used to represent the unknown. By this time, he had seen that X-rays could pass
through wood, paper, cardboard, cement, cloth, and even most metals—but not lead.
For this experiment, Roentgen coated a sheet of paper with barium platino-cyanide (a
kind of fluorescent salt) and hung it on the far wall of his lab. When he connected power to
his Crookes’ tube, the fluorescent sheet glowed a faint green. When he held an iron disk in
front of the paper, the paper turned back to black where the iron disk blocked the X-rays.
Roentgen was shocked to also see the outline of every bone in his hand and arm in faint
green outlines on the fluorescent paper. When he moved a finger, the bones outlined in
glowing green also moved.
On seeing these first X-ray images, Roentgen’s wife shrieked in terror and thought that
the rays were evil harbingers of death. Roentgen, however, began six weeks of intensive
study before releasing his results on the nature and potential of X-rays.
Within a month Wilhelm Roentgen’s X-rays were the talk of the world. Skeptics called
them death rays that would destroy the human race. Eager dreamers called them miracle
rays that could make the blind see again and could beam complex charts and diagrams
straight into a student’s brain.
Doctors called X-rays the answer to a prayer.
Fun Facts: The Z Machine at the Sandia National Laboratories, New
Mexico, can, very briefly, produce X-rays with a power output roughly
equivalent to 80 times that of all of the world’s electrical generators.
More to Explore
Aaseng, Nathan. The Inventors. Minneapolis, MN: Lerner Publications, 1998.
Claxton, Keith. Wilhelm Roentgen. London: Heron Books, 1994.
Dibner, Bern. Wilhelm Conrad Röntgen and the Discovery of X-Rays. New York:
Franklin Watts, 1998.
Esterer, Arnulf. Discoverer of X-Rays: Wilhelm Roentgen. New York: J. Messner,
1997.
Garcia, Kimberly. Wilhelm Roentgen and the Discovery of X-Rays. Hockessin, DE:
Mitchell Lane, 2002.
Nitske, Robert. The Life of Wilhelm Conrad Röntgen, Discoverer of the X-Ray. Tucson:
University of Arizona Press, 1996.