In 1903 a French physicist named René Prosper Blondlot announced the discovery of a subtle and mysterious form of radiation he called N-Ray. Blondlot announced the discovery of N-Rays shortly after Roentgen discovered X-Rays.
N-Rays were refracted by metal prisms. They were blocked by wet paper. Blondlot's results were independently confirmed in dozens of other labs in 1903 and 1904.
In 1904 a visiting American physicist, Robert W. Wood, visited Blondlot's lab, and was invited to view N-Rays for himself. The viewing had to be done in total darkness, after the experimenter's eyes had adapted to the darkness. Wood took the opportunity to remove a key piece of Blondlot's apparatus. Nevertheless Blondlot described to Wood what he should be seeing. Wood did not reveal that he had tampered with the apparatus until the lights had been turned back on.
The story of the discovery of N-Rays, the early confirmations, and later repudiations, is one of the cautionary parables of Science with which skeptics greet startling announcements, like that of cold fusion.