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Blondlot and N-rays

One of the first things I did with every graduate student who worked with me is to convince them how difficult it was to keep oneself from unconscious bias.*--Michael Witherell, head of Fermi National Accelerator Laboratory

René Prosper Blondlot (1849-1930) was a French physicist who claimed to have discovered a new type of radiation, shortly after Roentgen had discovered X-rays. He called it the N-ray, after Nancy, the name of the town and the university where he lived and worked. Blondlot was trying to polarize X-rays when he claimed  to have discovered his new form of  radiation. Dozens of other scientists confirmed the existence of N-rays in their own laboratories. However, N-rays don't exist. How could so many scientists be wrong? They deceived themselves into thinking they were seeing something when in fact they were not. They saw what they wanted to see with their instruments, not what was actually there (or, in this case, what was not there).

The story of  Blondlot is a story of self-deception among scientists. Because many people have the misguided notion that science should be infallible and a fount of absolutely certain truths, they look at the Blondlot episode  as a vindication of their excessive skepticism towards science. They relish accounts such as the one regarding Blondlot and the phantom N-rays because it is a story of a famous scientist making a great error. However, if one properly understands science and scientists, the Blondlot episode indicates little more than the fallibility of scientists and the self-correcting nature of science.

Blondlot claimed that N-rays exhibit impossible properties and yet are emitted by all substances except green wood and certain treated metals. In 1903, Blondlot claimed he had generated N-rays using a hot wire inside an iron tube. The rays were detected by a calcium sulfide thread that glowed slightly in the dark when the rays were refracted through a 60-degree angle prism of aluminum. According to Blondlot, a narrow stream of N-rays was refracted through the prism and produced a spectrum on a field. The N-rays were reported to be invisible, except when viewed as they hit the treated thread. Blondlot moved the thread across the gap where the N-rays were thought to come through and when the thread was illuminated it was said to be due to N-rays.

Nature magazine was skeptical of Blondlot's claims because laboratories in England and Germany had not been able to replicate the Frenchman's results. Nature sent American physicist Robert W. Wood of Johns Hopkins University to investigate Blondlot's discovery. Wood suspected that N-rays were a delusion. To demonstrate such, he removed the prism from the N-ray detection device, unbeknownst to Blondlot or his assistant. Without the prism, the machine couldn't work. Yet, when Blondlot's assistant conducted the next experiment he found N-rays. Wood then tried to surreptitiously replace the prism but the assistant saw him and thought he was removing the prism. The next time he tried the experiment, the assistant swore he could not see any N-rays. But he should have, since the equipment was in full working order.

According to Martin Gardner, Wood's exposure of Blondlot led to the French scientist's madness and death (Gardner, 345 n.1). Robert T. Lagemann (1977) puts the lie to that notion, apparently first put forth by William Seabrook in his biography of Wood. Lagemann writes that he talked with E. Pierret, a retired chief assistant in the physics department at Nancy. Pierret told him he had known the assistants who worked with Blondlot and he had "talked with Blondlot in 1926, at which time Blondlot did not appear to have lost his intellectual powers. Blondlot, he said, continued to believe in the existence of N rays after he stopped his active study of them in 1906...."

Actually, Blondlot continued in his post of Professor of Physics for six years after Wood’s disclosure. He retired in 1910  at the age of 61, before the usual age of retirement. He lived for 20 years in retirement, until his death in 1930 at the age of 81. During that period he held the title Professor Honoraires (i.e., emeritus) and continued to live in his large home at 16-18 Quai Claude le Lorrain. He continued to have associations with others at the University, as when for example, in 1909, on the occasion of the unveiling of a monument of his friend, Ernest Bichat, Blondlot made one of the speeches. In 1923, a third edition of his book on thermodynamics appeared, and in November 1927, he wrote a new preface for a third edition of his textbook on electricity. Certainly his long will, frequently revised to accommodate changing conditions, which was duly accepted and probated upon his death, is one prepared by a sane man.

Nor is there any evidence that he committed suicide, as is sometimes inferred by those who read Seabrook. Blondlot lived some 26 years after Wood’s exposure. Had he taken his own life, he probably could not have been buried in a Catholic cemetery with the full rites of the Church, as was indeed the case according to newspaper accounts. Cemetery records show he is buried in the Cimetiere de Preville, the central one of the city.

So, Blondlot did not go mad and did not commit suicide, but he did persist in his N-rays delusion.

Were Blondlot and those who verified his N-ray experiments stupid or incompetent? Not necessarily, since the issue isn't one of intelligence or competence, but of the psychology of perception. Blondlot and his followers suffered "from self-induced visual hallucinations" (Gardner, loc. cit.).

What is the lesson from the Blondlot episode? James Randi writes

...science does not always learn from these mistakes. Visiting Nancy recently and speaking on the subject of pseudoscience, I discussed this example and though I was in the city that gave the name to N-rays, no one in the audience had ever heard of them, or of Blondlot, not even the professors from the University of Nancy!
--James Randi at Cal Tech

The fact that Blondlot is not remembered at Nancy ought to be taken as a sign that science does learn from its mistakes. The fact that Blondlot is not considered a prophet in his homeland is a healthy sign that although scientists often make errors, even big ones, other scientists will uncover the errors and get science back on the right path to understanding nature. Those who think that science should be infallible do not understand the nature of science.

Recent examples of "Blondlot's Folly" are Pons and Fleischmann's discovery of cold fusion (1989), Jacques Benveniste's water memory claims (1988), and the Lawrence Berkeley National Laboratory in California's claim to have discovered ununoctium or element 118 (1999), although the latter seems to be marred by faked data.

See also Charles Fort and the Forteans, confirmation bias, pathological science, Piltdown hoax, and pseudoscience.

reader comments

further reading

books and articles

Ashmore, Malcolm. "The Theatre of the Blind: Starring a Promethean Prankster, a Phony Phenomenon, a Prism, a Pocket, and a Piece of Wood," Social Studies of Science, Vol. 23 (1993), 67-106.

Asimov, Isaac, "The Radiation That Wasn't," The Magazine of Fantasy and Science Fiction, March, 1988; also in Out of the Everywhere (1990).

Gardner, Martin. Fads and Fallacies in the Name of Science (New York: Dover Publications, Inc., 1957).


James Randi at Cal Tech

The Rise and Fall of N-Rays by Mike Epstein

What Ever Happened to n-Rays? by Terence Hines and The n-Rays by Robert W. Wood

Last updated 27-Oct-2015

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