6-1-435. Herr Jordan à H. Poincaré

Wilmersdorf, Ringbahnstr. 19, 14.10.1910

Monsieur !

Où est la politesse française ? Est-ce permis de faire venir mille personnes et après l’arrivée les désappointer? Et pourquoi? À cause d’une maladie? Où d’un accident? Oh non! en vérité à cause d’une invitation à la cour royale! Ce n’est pas une excuse suffisante, car un devoir est plus important qu’une invitation.

Agréez, monsieur, l’expression de mon indignation profonde

Jordan

conseiller au tribunal de Berlin

ALS 2p. Collection particulière, Paris 75017.

Time-stamp: "17.06.2026 22:13"

Notes

• 1 Herr Jordan is upset. Poincaré represented the Paris Academy of Sciences at the centennial commemoration of the foundation of the University of Berlin, from 10 to 13 October, 1910. On 11 October, the Brandenburg Academy voted to present Poincaré for membership in the Order “Pour le mérite”, replacing Giovanni Schiaparelli (Archives BBAW Historische Abteilung II-X, 17, Orden Pour le mérite). The same day, the Minister for Religion, Education and Health awarded Poincaré a commemorative medal (§ 6-1-2058). Poincaré was scheduled by three different groups to give lectures on the 12th and 13th of October. On the 12th, he spoke at 6 p.m. on the topic of curves traced on an algebraic surface before the Berliner Mathematische Gesellschaft (Poincaré 1911b; Jahresbericht der deutschen Mathematiker-Vereinigung 19, 1910, 225). On the morning of the 13th, at the behest of the Mathematical Union of the University of Berlin, Poincaré lectured at 10:00 a.m. on the topic of “some equations of the theory of Hertzian waves”, at Münzstrasse 8, according to the notice in the Tägliche Rundschau of 8 October (p. 3 of the evening edition). A third talk, organized by the Wissenschaftlicher Verein in the auditorium of the Urania Institute on Taubenstrasse, was advertised in the Tägliche Rundschau of 13 October for 8 p.m. that same day, as follows: “Donnerstag 8 Uhr: Wissenschaftlicher Verein: Professor H. Poincaré (Paris): La mécanique nouvelle”. This announcement is evidence of a scheduling error, as Poincaré was invited to dinner at the Royal Palace by Kaiser Wilhelm II that same evening. Undoubtedly, there were many disappointed spectators at Urania that evening, including Mr. Jordan. According to the account published by the Tägliche Rundschau on 14 October (p. 3), Poincaré delivered his morning lecture before the Mathematische Verein, and he attended the Kaiser’s dinner in the evening. The newspaper reports that he delivered his talk to the mathematicians in German, and that it was attended by Professors Schwartz, Jahnke, Marr, Dziobek, and “numerous auditors”. When Poincaré’s text was subsequently published in German (Poincaré, 1911c), a note affirmed that the lecture was delivered in Berlin on 13 October 1910. As for the lecture advertised at Urania, it appears that it took place, but not on the 13th, and perhaps at a different location. The Urania Institute advertised talks by others on the evenings of the 14th and 15th October in the Tägliche Rundschau. According to Lebon’s bibliography (Lebon, 1912, 90), Poincaré lectured in French on the 14th of October at the University of Berlin on “la mécanique nouvelle”. This would suggest that Poincaré’s lecture was rescheduled for the 14th at a different venue. However, according to one auditor, Poincaré spoke in German at the Urania Institute on the 13th before a “modestly-sized audience” (Moszkowski, 1920, 15). A Urania publication from 1913 affirms only that the lecture took place (Anonymous, 1913, 41). Poincaré’s manuscript in French was translated to German by Urania’s director, Paul Schwahn, and published in Himmel und Erde (Poincaré, 1911a), the monthly of which Schwahn was co-founder and director. A note to Poincaré’s article affirms rather coyly that the lecture was held in the “Wissenschaftlichen Verein” in Berlin, in other words, Schwahn provided no precise information concerning the date and location of the lecture.