Although
his lab notes were burned after his death in 1923, Röntgen’s biographers
describe him noticing a faint glow from a screen covered in fluorescent
material about a metre away from his apparatus. This was despite the vacuum
tube itself being covered with black cardboard that stopped all visible light.
Having
reasoned that the tube itself must be giving off these invisible rays, Röntgen
conducted a series of experiments over the next few weeks in which he found
that they could pass through certain objects but not others. Due to his
uncertainty over the exact nature of the new rays, he adopted the mathematical
designation ‘X’ to reflect their mysterious nature.
As his
experiments continued, Röntgen began to notice that the rays were able to
penetrate the soft tissues in his body but were stopped by bone. After
subsequently replacing the fluorescent screen with a photographic plate he made
the first ever X-ray image clearly showing the bones of his wife Bertha’s hand
and her wedding ring. On seeing the image, she is said to have remarked, ‘I
have seen my death.’
Röntgen
published the paper “On a New Kind of Rays” on 28 December 1895, and news of
his discovery spread quickly. Within a year X-rays were being used as far away
as the United States as both a diagnostic tool and for treating cancers.
Röntgen refused to take out a patent on X-rays in order to allow the entire
world to benefit from them but was awarded the first ever Nobel Prize in
Physics in 1901.
His citation referred to his discovery as the
“remarkable rays”. Röntgen refused to patent his discovery and gave the money
that came with the Nobel Prize to his university.
