Radlof, Johann Gottlieb
Johann Gottlieb Radlof (1777-1829) was a German linguist, who from 1818 to 1822 held a professorship at the University of Bonn and from 1823 to 1826 he taught at the University of Berlin. His later research led to an investigation of catastrophes in the solar system and their effects on the Earth.
Radlof’ supported his claim of cataclysmic celestial encounters with some material  later employed by Immanuel Velikovsky over a century later. Some commentators have mentioned how Velikovsky seemed reluctant to credit earlier writers, such as W.C.Beaumont and Radlof(a), with their contributions to the development of the theory of planetary Catastrophism. Others, such as Clube & Napier offer a more generous attribution(b).
(b) Johann Gottlieb Radlof – Atlantisforschung.de (atlantisforschung-de.translate.goog)