Three months later, on his way back to Europe, he makes the decision to resign from his Berlin position. Since the German citizenship had been tied to his position at the Academy of Sciences, it is his understanding that his resignation would also entail the loss of the latter. Yet, in order to be on the safe side, immediately after his arrival in Antwerp, he turns to the German consulate in Brussels, to receive instructions about how to relinquish the German citizenship.