The elusive N-rays

At the beginning of the 20th century, the world of science stormed around new rays that were discovered and that have interesting properties, what happened when they were tested by skeptical scientists

At the beginning of 1903, eight years after the discovery of X-rays (by the German Wilhelm Roentgen), news spread among French scientists about the discovery of a new type of radiation. Rene Blondlot, one of the famous physicists of that time, discovered this radiation and called it N-radiation, in honor of the city where it was discovered - Nancy.

Blondlot noticed that the radiation causes the electrical discharges it passes through to appear brighter. He split the N-rays into different frequencies with an aluminum-coated prism (similar to splitting a white light beam into the colors of the rainbow with a glass prism), and performed a series of measurements and experiments to characterize that radiation.

Soon, different sources were discovered that emit these rays, different detectors that can detect it, and different materials that transmit or block it (dry cigarette paper, for example, transmits N-rays, but wet does not).

Many researchers (mainly in France) began experimenting with the new radiation, and discovered a host of amazing phenomena. For example, Augustin Charpentier, distinguished professor of biophysics at the medical school, discovered that rabbits and frogs emit N-radiation, muscles emit it but tendons do not. He discovered that exposure to N-rays increased the sensitivity of the eye, sense of smell and hearing. He noticed that the radiation emanating from living creatures was slightly different from normal N-radiation, and called these rays "physiological rays". It was also found that these rays can be transmitted through a wire.

The amount of discoveries that accumulated around N-rays in just three years was so great that 60 pages were required just to list the various phenomena that were discovered. In total, about 300 articles by 120 scientists were published on the subject.

To illustrate the magnitude of the enthusiasm surrounding the discovery, we note that two physicists and one spiritualist claimed to be the original discoverers of N-rays, claims that were examined by the French Academy of Sciences.

But not everyone was able to reproduce the findings. Other famous scientists tried to measure the effects of N rays but without success.

What happens when a sharp minded person arrives on the scene

Robert Wood was an American physicist best known for the study of ultraviolet (UV) radiation. His areas of interest were many and varied, and included, among other things, solving crimes using scientific methods and investigating the exploits of spiritualist mediums. When he heard about the new horns that were discovered in France, he dropped by to see what it was all about.
Here are excerpts from what Wood says In a letter published in Nature Towards the end of 1904 (my free translation):

"The failure of a large number of experienced experimental physicists to find any evidence of the existence of N-rays, and the incessant stream of publications concerning more and more amazing phenomena of these rays, stimulated me to visit one of the laboratories where these findings were demonstrated. I set out surrounded by doubts, I must admit, but with the hope that I will be convinced of the reality of the phenomenon.

After spending [wasted?] 3 hours or more observing various attempts, not only was I unable to report a single observation that could testify to the existence of this radiation, but I was convinced that those researchers who received positive findings were deluding themselves in one way or another.

The first experiment I witnessed was the change in brightness of an electric spark when N rays are focused on it by means of an aluminum lens. It is claimed that it is very easy to notice the differences in brightness, but I was not able to notice even a slight change. It was explained to me that my eyes are probably not sensitive enough. I suggested to the researchers that they try to identify when I block the N-rays with my hands, by watching the brightness of the spot on the screen (without knowing when I block the rays). In no case was a correct answer given. The spot was pronounced alternately light and dark while my hand continuously blocked the path of the rays. Even when I removed it, the reports continued to arrive regardless of the movement of the blocking hand."

At this point, Wood moved to another trick: under the cover of darkness that prevailed in the room where a demonstration was held, Wood removed the saw that was the most critical component of the experimental set-up. The researchers continued to report the same pattern of N-rays, even though such a pattern could not have been seen in a situation where the prism was not in place! (If it was right in the N rays, of course).

In another experiment, some spots of phosphorescent paint were supposed to change their sharpness as a result of moving a metal plate back and forth near them. Wood continued his antics: "I could not notice any difference, even though I was told that the phenomenon is not in doubt and the changes are very obvious to the eye. While holding the metal plate behind my back I moved my arm back and forth in relation to the screen. The researchers continued to describe the same changes."

An example of one of the experimental setups

After a few more embarrassing revelations, he concludes:

"I have to admit that I left the laboratory with a strong feeling of depression. Not only did I not see a single convincing experiment, but I was almost completely convinced that all the brightness changes that were reported (and were the only evidence for the existence of N-rays) were the product of imagination only. It seems strange that after a year's work on the subject, not even one experiment was planned that could convince a critical observer that the rays even exist."

Wood offers an example of an experiment that "could have decided the issue beyond any doubt", and is based on the double-blind principle: suppose you want to test the claim that a panel of type A transmits N rays while a panel of type B blocks them. All that is required is for one researcher to randomly insert panel A or panel B into the path of the beam (let's say according to the result of a coin toss), and another researcher who does not know which panel was inserted indicates whether he recognizes the effect of the rays on the experimental set-up. In this way the second researcher does not know if he is "supposed" to see a radiation effect or not. This exercise clears his desire to see a particular thing from influencing the results of the experiment. After repeating this many times, check the degree of compatibility between the type of board placed each time by one researcher and the reports of the other researcher. If the match is perfect or high - there is probably a real phenomenon. If there is no match - the phenomenon probably does not exist in reality.

The publication of Wood's report had an overwhelming effect. Only one study supporting the existence of N-rays was published after this embarrassing revelation. Blondlot himself, who retired in 1909, was convinced of the existence of his horns at least until 1926.
How do 120 scientists manage to measure something that doesn't exist?

The existence of N radiation was inferred based on visual evidence only (slight brightness changes between light spots). Since it was the researchers' brains that interpreted what they saw there (and not an "objective" measuring device), their expectations and desires influenced what they actually saw.

The scientists unconsciously tricked themselves into seeing what they expected to see, or as Gardner put it - they suffered from a "self-induced visual hallucination".

What is interesting in this case is the spread of "seeing the expected" among an entire community of people, that is, even repeating the experiments in other laboratories and with other equipment was not enough to shatter the illusion! This is an example of mass delusion.

The simple thing that all those scientists failed to do was question their very senses. To try to fail themselves, to put themselves and one of his friends to a simple test that will clear the biases of seeing the expected and desired.
An example of the weakness of science or its strength?

Those who do not understand the essence of the scientific enterprise mistakenly believe that science should be infallible and yield only absolute truths. They see the N-ray affair as a case that weakens science: "Look, even great scientists make big mistakes!"

But this affair demonstrates exactly the opposite - it demonstrates the resilience of the scientific enterprise to overcome the weaknesses of the specific scientists (whether it is self-deception, intentional charlatanism, obscurity or stubbornness, jealousy, personal revenge, a desire for publicity or any other human trait).

The N-ray incident is studied as a historical lesson about the dangers lurking in experiments that are not properly planned. A properly designed experiment cleans up the researchers' influence on the results, for example by using a double-blind protocol. This was exactly the essence of the "pranks" that Wood performed during his visit, and which were shattered in a few hours and a year of intensive research.
And here lies one of the main differences between science and pseudo-science. In science, such a mass illusion is shattered in a short time, and thrown into the "failures and lessons learned" drawer. In the realms of pseudo-science this does not happen: any researcher's self-delusion continues to thrive for decades or even hundreds of years. Thousands of believers continue to adhere to it even in the face of simple experiments that completely disprove it, and within the framework of studies and training in that pseudo-scientific field, this mass illusion is passed on to future generations.

Sources:

• N rays on the rexresearch website
• N-rays on Wikipedia
• N rays in the dictionary for the skeptic
• N rays on skeptic.com