Most scientific historians view the beginning of modern physics as 1895, when Wilhelm Röntgen published an X-ray discovery paper. This is probably because the X-ray discovery has had a profound impact on the development of modern physics, including radiology, nuclear physics, and quantum mechanics. How did the experiment of Rötgen that started with a false hypothesis lead to a great discovery? I have reconstructed the moment of discovery from Röntgen’s perspective.

To illustrate more vividly, I used Röntgen’s articles as well as his experimental notes, interviews, and related papers. I would like to say that the subjective feelings and thoughts in the following article are not quoted from the author’s point of view, but are quoted from Röntgen’s data.

Wrong hypothesis and experiment

It was late Friday afternoon, Friday, November 8, 1895, when Professor Röntgen was able to resume the cathode ray tube experiment. Over the last year, the University of Würzburg has been working with the Dean. As soon as the dean finished his term, Röntgen resumed his research on cathode ray tubes.

Before the power is turned on (Left) Cathode tube (Crookes Tube) and high voltage (right) when the appearance. When the cathode ray hits the glass tube, green fluorescent light appears. A cross-shaped shadow appears in the glass tube, indicating that the cathode can not penetrate the common metal. Ⓒ Wikipedia
Before the power is turned on (Left) Cathode tube (Crookes Tube) and high voltage (right) when the appearance. When the cathode ray hits the glass tube, green fluorescent light appears. A cross-shaped shadow appears in the glass tube, indicating that the cathode can not penetrate the common metal. Ⓒ Wikipedia

The cathode ray tube phenomenon was a mystery that caused mysterious fluorescent light from the cathode ray of red light passing through the glass tube without air. What does a cathode ray passing through a vacuum react with and light like this? It stimulated the curiosity of many scholars, but no one could explain the phenomenon properly. Some scholars say that cathode rays are the result of reaction with a virtual medium, ether, and even some scholars claim to be some ectoplasm.

Rogen was preparing his experiments in May of 1894, one year before Phillpp Lenard, famous for cathode ray studies, inquiring about cathode ray experiment equipment. Rogen’s experiment was to measure the cathode ray passing through the glass tube. The mysterious fluorescent light is what happens when a cathode ray is transmitted through a glass tube.

The idea of ​​Rogen is a scientifically false hypothesis. At that time, it is widely known that cathode rays can not pass through glass tubes, but Röntgen believes that a very small amount of cathode ray can emerge. He made this hypothesis because of the cathode ray experiment of Leonard. Leonard created a device through which the cathode ray could penetrate a very thin metal (aluminum) plate. It is believed that glass can also permeate because metals can also penetrate.

Assuming that the cathode ray passing through the glass tube would be very weak in intensity, Röntgen completely wrapped the cathode ray tube with black cardboard to block the bright cathode ray tube light. And the laboratory was completely darkened. And a high-voltage current was passed through the cathode ray tube. Rogen carefully observed the experimental setup, but no light came out of the cathode ray tube.

Instead, he looked at the experimental equipment and glanced at the dim light. I thought that the cathode ray tube was less obscured, and black cardboard was carefully cut off and tested again, and I confirmed that the faint flicker was coming from the side of the chair opposite the experiment device. He wondered why the light came from the chair, and Rutgen lit up the laboratory and started looking at the chair. He was shocked when he checked the object placed on the desk next to the chair.

It was a platinum cyanide barium paper that emitted fluorescent light when a cathode ray hits. It was prepared to check the cathode ray through the glass tube wrapped in cardboard. Can a cathode ray that can only fly about three centimeters in the air reach the top of a desk a few meters away? Rutgen felt that reacting with platinum cyanide paper was a different kind of light than a cathode ray.

The moment of X-ray discovery

Röntgen was excited and started experimenting to find out what this invisible light was. I spent the night during the weekend, then I ate in the lab all the time and continued experimenting repeatedly. Books over 1000 pages, 2.5 cm thick aluminum panels, and 5 cm thick wooden planks could not completely prevent this light.

When Röntgen picked up the lead box, which is the heaviest metal in the lab, by hand and touched the light, platinum cyanide barium paper showed another stunning scene. There was something very faintly printed on the side of the shadow of the lead box that caused this light to block.

Surprisingly, it was a shadow of a finger bone. It is the moment when X-rays are found.

Röntgen, who had never seen his fingertips faintly reflected on a sheet of platinum cyanide barium paper, was afraid. At first, I had been experimenting for several days while I was experimenting. However, as he continued to see the same phenomenon, he had a terrible idea that his mind was strange, and that there was an ectoplasm on the cathode.

Röntgen, who could not scientifically explain the transmission of X-rays, could not tell others about this phenomenon. Nobody would believe it, and it would seem that the reputation that he had built up as a scientist for the time being would fall down at once. We needed the proofs and testimonials that would undoubtedly prove the bizarre phenomenon that this invisible light produces.

Record invisible light

Is there any way to clearly record the phenomenon created by this invisible light? It was the photographic plate that came into the eyes of Rantgen who was worried. In 1879, a photographic plate was invented, and in 1895 it was popular to take pictures at a photo studio.

Three days before Christmas, December 22, Röntgen prepared a photographic plate and invited his fiancé, a person who would believe in himself, even if the experiment failed, to the lab. And I took an X-ray of the hand of the fiancee with the engagement ring. The two people who finally saw the developed picture screamed. Röntgen is in the joy of proving that he is not crazy, and the fiancee is in terrible shape with his bones. When the fiancée saw this picture, she was afraid, “I seem to see my body becoming a corpse.”

The x-ray photograph taken by the fiancee’s hand was objective evidence to prove that there is invisible light in itself.

The cathode ray tube phenomenon has already been under study for several years by several scholars, and Rogen has quickly prepared the results of the experiment.

Röntgen discovered this phenomenon of invisible light, but could not explain it scientifically. He named this light X-ray (X in the sense that it is unknown).

His dissertation, which included photographs of his fiance ‘s hand, was sent to his College of Physics and Medicine on December 28, 1895. It was only 50 days after X-ray was discovered.