Blondlot reported that N-rays were produced by many types of matter, both living and inert (everything except green wood and some treated metals), and that their strength increased with the “psychic activity” of the source. His experimental setup included a hot wire inside an iron tube to generate the N-rays, which were then refracted through a 60-degree angle prism of aluminum, and in turn were detected by a calcium sulfide thread that would glow slightly. The subtle glow could only be perceived in the dark by those with sharp vision.
