Pourquoi Louis de Broglie n'a pas démissionné en 1944.... Un document inédit issu du nouveau fonds Borel de Saint-Affrique.

In February 1942, the Académie des sciences (France) proceeded - following the death of Émile Picard in December 1941 - with the election of his successor to one of the two positions of permanent secretary. Under ordinary circumstances, the post should have gone to the dean of the mathematics section, Jacques Hadamard. However, as a target of Vichy’s antisemitic policies, he was no longer an admissible candidate. Next on the short implicit list of natural candidates was Émile Borel. Yet, in the wake of his recent arrest by the Gestapo and his detention for several weeks at Fresnes prison, he was sidelined under obscure circumstances in favor of the physicist Louis de Broglie. In a 2011 article, Mazliak and Shafer explained how, after the Liberation of Paris in August 1944, Borel attempted to persuade de Broglie to resign so that he might take up the position of permanent secretary. The reasons why Louis de Broglie ultimately chose to remain in office – despite early signs suggesting an imminent resignation – had nevertheless remained elusive. The present short note originates in the discovery of three archival documents from a collection recently unearthed in Saint-Affrique, a French town in the Aveyron département, in the southwest of France, where Borel was born and where he served as mayor for over a decade. This collection contains hundreds of letters addressed to Borel and his wife. Among these was found one from Louis de Broglie, dated late October 1944, reproduced in full in this note. To illustrate the material aspect of the document, a photographic reproduction of an excerpt of the original accompanies this previously unpublished transcription. In it, de Broglie sets out the reasons why he ultimately decided not to resign from the secretaryship. Two further documents are also reproduced, including a circular letter from Louis de Broglie to the members of the Académie. These documents are accompanied by a brief historical contextualization and a very concise interpretative commentary, amounting to only a few lines.