Verniana — Jules Verne Studies / Etudes Jules Verne — Volume 3 (2010–2011) — 125–130
Sur la trace des “kritiskshalhen” du professeur Friedrich
The "ultra X rays of professor Friedrich of Elbing" that Jules Verne mentions in Le Testament d’un excentrique do not come from the author's imagination. The trace of their discovery can be followed from a meeting of the Vienna Academy of Science to an article in the Revue scientifique, which Jules Verne used to read.
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