Ivan Puluj in the UK. While Professor Puluj's finding were essentially X-rays, he did not recognise them as such at first, although he demonstrated X-ray pictures of a hand and fingers obtained by using his tube / lamp to his students. This credit later went on to Wilhelm Conrad Röntgen. Once Roentgen visited Professor Puluj's laboratory and the latter presented one of his tubes to Roentgen. Roentgen went home and in his laboratory started to conduct experiments with Puluj's tube. Puluj also continued to do research with his X-ray tubes. On 8 February 1896, just 6 weeks after Röntgen presented his finding
Multiple discovery independent discovery". Robert K. Merton defined such "multiples" as instances in which similar discoveries are made by scientists working independently of each other. Merton contrasted a "multiple" with a "singleton"—a discovery that has been made uniquely by a single scientist or group of scientists working together. As Merton said, "Sometimes the discoveries are simultaneous or almost so; sometimes a scientist will make a new discovery which, unknown to him, somebody else has made years before." Commonly cited examples of multiple independent discovery are the 17th-century independent formulation of calculus by Isaac Newton, Gottfried Wilhelm Leibniz and others, described by A.