http://www.skeptic.com/01.1.randi-paranormal.html

"I want to close this presentation with some parallel examples of scientific claims that turned out to be so much nonsense. Let's go back to 1903 in France. You may have heard of this, if not it really is something you should look up. A prominent scientist - a physicist named Rene Blondlot - startled the world of science with his announcement of the discovery of N-rays. A very well respected man who had won many prizes in science and justifiably so, he was doing experiments by today's standards that were very simple - such as finding the speed of electricity in a conductor. It sounds easy today, but in those days it was a very sophisticated experiment and not all that easily done. Blondlot was in his 70s at the time when he discovered N-rays, named after the town of Nancy, where he was head of the Department of Physics at the University of Nancy."

"What were N-rays? N-rays were allegedly radiation exhibiting impossible properties emitted by all substances with the exception of green wood (wood not dried out) and anesthetized metal. (Metal that had been dipped in ether or cholorophorm did not give out N-rays!) Within a matter of six to eight months of the announced discovery of N-rays, 30 papers had come in from all over Europe confirming the existence of N- rays. Reports were published in journals despite the fact that there were many laboratories reporting failure after failure in replicating the results. Such acceptance was understandable considering that X-rays, which also exhibited unsuspected properties, were by then firmly established."

"What Blondlot had was a basic spectroscope with a prism (not glass, but aluminum) on the inside, and a thread. The narrow stream of N-rays was refracted through the prism and coming out produced a spectrum on a field. The N-rays were reported to be invisible, except when viewed when they hit a treated thread (for example, treated with calcium sulfide). They moved the thread across the gap where the N-rays came through and when it was illuminated that was reported as the detection of the N- rays."

"Before long N-rays were established as factual. Nature magazine was skeptical of the N-rays since laboratories in England and Germany were unable to find them. (Germany had just discovered X-rays the decade before and the French were annoyed that they didn't have a ray.) Nature sent an American physicist named Robert W. Wood from Johns Hopkins University to investigate. Now, I've been accused of skulduggery in my time, but what Wood did was brilliant. When no one was looking he removed the prism from the N-ray detection device and put it in his pocket. Without the prism the machine could not possibly work because it was dependent on the refraction of N-rays by the aluminium-treated prism. Yet, when the assistant conducted the next experiment he found N- rays! He swore they were there."

"When the experiment was over Wood knew it was really over. He was prepared to make his report, and when he went to replace the prism back in the machine, one of the other assistants saw him do this and thought he was actually removing it, and he decided to show Wood up. Thinking Wood had removed the prism (when he had actually put it back), he set up the experiment, could find no lines, and opened the box to show that the prism was not there and to his dismay, there it was! The whole incident blew up. Papers were withdrawn, those that were in the mail were retracted, and N-rays disappeared from the scene."

"How did this happen? How did over 30 papers get published? Not because the scientists who wrote the papers were stupid. Not because they were lying. But because they were deceiving themselves.