Giant shadows that seemed to move by themselves due to movement of the cloud layer (this movement is another part of the definition of the Brocken spectre), and that were surrounded by glories, may have contributed to the reputation the Harz mountains hold as a refuge for witches and evil spirits. In Goethe's Faust, the Brocken is called the Blocksberg and is the site of the Witches' Sabbath on Walpurgis Night. Theory Modern theories of light, first described by Henri Poincaré in 1887, are able to explain the phenomenon of glories through the complex angular momentum (rotation) of the electromagnetic field of a light wave, and do not need quantum theories. A summary of rainbowlike phenomena was provided in Scientific American in 1977, and states: Most 20th century work on the phenomenon of rainbows and glories has focused on determining the correct intensity of light at each point in the phenomenon, which does require quantum theories. In 1947, the Dutch astronomer Hendrik van de Hulst suggested that surface waves are involved. He speculated that the brightness of the coloured rings of the glory are caused by two-ray interference between "short" and "long" path surface waves—which are generated by light rays entering the droplets at diametrically opposite points (both rays suffer one internal reflection). A theory by Brazilian physicist Herch Moysés Nussenzveig suggests that the light energy beamed back by a glory originates mostly from classical wave tunneling (synonymous in the paper to the evanescent wave coupling), which is an interaction between an evanescent light wave traveling along the surface of the drop and the waves inside the drop. In culture C. T. R. Wilson saw a glory while working as a temporary observer at the Ben Nevis weather station. Inspired by the impressive sight, he decided to build a device for creating clouds in the laboratory, so that he could make a synthetic, small-scale glory. His work led directly to the cloud chamber, a device for detecting ionizing radiation for which he and Arthur Compton received the Nobel Prize for Physics in 1927. In China, the phenomenon is called Buddha's light (or halo). It is often observed on cloud-shrouded high mountains, such as Huangshan and Mount Emei. Records of the phenomenon at Mount Emei date back to A.D. 63. The colourful halo always surrounds the observer's own shadow, and thus was often taken to show the observer's personal enlightenment (associated