On November 8, 1895, by chance, the invisible became visible: they discovered x-rays. The story, which earned its protagonist the Nobel Prize for physics in 1901, changed history forever, certainly that of medicine. It was a casual discovery, as mentioned, made by trying to do another experiment. A typical case of scientific serendipity mentioned many times. Among those who, in my opinion, the scientific journalist Stefano Dalla Casa told the best, for the website of the Foundation for Cancer Research (AIRC), Wonder Why.
Here is what Dalla Casa writes: “(…) When he discovered the X-rays, (Wilhelm) X-ray he was fifty years old. He was born in Lennep, Germany, the only child of Friedrich Conrad Röntgen, a textile merchant, and Charlotte Constanze Frowein, of a Dutch family. When Wilhelm was three, the Röntgens migrated to Apeldoorn, Holland, where their son would attend the Instituut van Martinus Herman van Doorn, the boarding school where he developed his love for mechanics. In 1862 he enrolled in the technical institute in Utrecht, but after a year he was expelled: he had been unjustly accused of having designed the caricature of a teacher, and did not mean the name of the person in charge. He tried to win the diploma by studying privately but, according to what was reported by the biography by Otto Glasser (perhaps the best known scholar of the life of Röntgen), on the day of the exam he found himself in front of one of the professors who had had him expelled, and he did not pass the test.
He was unable to enroll in the city’s university, but he began to attend it as a guest in 1865. Meanwhile he discovered that at the prestigious Zurich Polytechnic on the other hand, it was also possible to access without a diploma, as long as you passed a entrance exam. Just in that institute, after passing the test, Wilhelm graduated in mechanical engineering (1868) and won his doctorate (1869) with a thesis on gas. Under the protective wing of Professor August Kundt, Röntgen began his university career, accepting positions in various German universities, until he settled permanently in Würzburg in 1888, after obtaining a professorship in physics at the city’s university. With him Anna Bertha Ludwig, whom he had married in 1872, and with whom he had adopted a child (daughter of Bertha’s brother). This is where our professor with an atypical curriculum had his “Eureka!” Moment.
November 8, 1895 X-ray was working with a tubo at Crookes, a device that can be considered the precursor of the cathode ray tube of televisions: it is a particular cone-shaped glass ampoule connected to a pump to create a vacuum and inside which two metal plates are placed, called electrodes (anode and cathode) , each connected to an electric generator. When the gas inside the tube is sufficiently rarefied, the flow of electricity causes light emission. By further reducing the gas pressure, i.e. making the vacuum even more severe, the emission of light ceases and a fluorescent spot can be observed on the glass wall in front of the cathode.
The fluorescence produced by the fixture is due to cathode rays. Back then no one knew that they were beams of particles called electrons, accelerated by the current from the cathode to the anode. Many materials hit by a radiation get excited by re-emitting other radiation, and this was exactly what happened in the tube when the accelerated electrons passed the electrodes and hit the glass wall. That day, however, Röntgen discovered the existence of an unknown radiation: X-rays, in fact. Like many colleagues, X-ray he wanted to understand more about the nature of cathode rays. Shortly before the German physicist Philip Lenard he had proven they could too exit the tube, through a thin aluminum window, and be detected on a screen coated with a nearby fluorescent substance. Röntgen repeated the experiment in one room, however, completely dark, and wrapped the tube with black cardboard, so that the light could not escape.
To his surprise, he saw a fluorescent plate light up a a few meters away, out of the reach of any cathode ray. The details of this chance discovery would later be told in many ways. One of the most famous legends tells that at that moment, leaning against the fluorescent plate in the laboratory, there was a book. Moving the slab, to his surprise Röntgen would have found the silhouette of a key, key then actually found by the scientist within the pages of the book. After that fateful November 8, 1895, X-ray he spent weeks in the lab, but at the end of December he published his first scientific article on the subject. A preliminary communication, modestly titled About a new kind of ray (“About a New Kind of Rays”), addressed to Medical Physics Society of Würzburg. The scientist also privately informed some colleagues, sending the printouts of the publication. (…) The first, famous, radiographic image of history (the one attached to Röntgen’s scientific publication) was that of left hand of Anna Bertha Ludwig, the physicist’s wife: they could clearly see each other the bones of the fingers and the marriage ring. In this regard, according to another anecdote, very picturesque but of uncertain source, Bertha in front of the image would have exclaimed: “I have seen my death” ”.
(for the rest, refer to the original article)
.