What, at best, has been mentioned in previous monographs about Himmler as the second most powerful man of National-Socialism in passing, the historian Franz Wegener develops in greater depth: Himmler's mind was open to diverse occult influences originating in Germany as well as France. Thus he wrote about a book of the German spiritualist, Carl du Prel, who experimented with hovering tables and mediums: "A small scientific work on a philosophical basis which truly has me believe in spiritualism and was the first to really introduce me to it." He received Gaston de Mengel, a British occultist, who wrote for the mysterious occult group of the Polaires in Paris, and who collaborated closely with the founder of the esoteric university in Nice. As researched by Wegener, Himmler purchased himself a manual for "pendulum practice and pendulum magic," and in this way came also in touch with the theory of the gnostic "Od." He believed in the "transmigration of souls," attempted to obtain horoscopes from a Munich astrologer and his various occult advisors, and agreed with the hypotheses of Karl Heise ("Okkultes Logentum," 1921) that occult powers were pulling the strings behind Communists, Jews, and Freemasons. On this background Wegener does not allow Himmler's tendency about occult subjects pass as a mere private matter: "If Himmler's image of the enemy with respect to Freemasonry and Jews was fed also by occult patterns, one can no longer speak of a 'private matter, ' since the political and, by no means, private consequence of Himmler's occult world view must be called mass murder."