DOCUMENTS 191, 192 DECEMBER 1909 223 ALS (Walter Habicht, Rodersdorf, Switzerland). [70 319]. "Moussonstr 12." in Einstein's hand in the upper left corner is omitted. [1]The year is provided by the reference to Einstein's course. [2]Paul Habicht. See the editorial note, "Einstein's 'Maschinchen' for the Measurement of Small Quantities of Electricity," pp. 51-55. [3]Very likely one or both of the volumes of Boltzmann's lectures on gas theory (Boltzmann 1896, 1898). Both volumes are in Einstein's personal library. Almost two years earlier Einstein had requested that Habicht return Boltzmann 1896. From Doc. 198 it appears that Einstein needed the book for a course in the kinetic theory of heat, which he gave in summer semester 1910 at the University of Zurich. Lecture notes for it are presented as Vol. 3, Doc. 4. 191. To Conrad Habicht [Zurich, 14 December 1909] Dem ordentlichen hochverdienten Mitglied Conrad Habicht die Akademie Olympia Der Präsident: A Ritter v. Steissbein.[1] Der Sekretär M. v. Insolvini. ADS (Walter Habicht, Rodersdorf, Switzerland). [12 412]. The torn envelope is addressed "Herrn Dr. Konrad Ha[bicht] Schiers Kt. Graubünden.," and postmarked "Zürich 10 Hottingen 14.XII.09.-3." [1]The name and title were given to Einstein by Conrad Habicht in Bern. Approached by a tradesman who wanted to engrave his name and title on a piece of tin, Habicht had the man engrave "Albert Ritter von Steißbein, Präsident der Akademie Olympia" on it instead, and af- fixed it to the entrance of Einstein's apartment. On returning home and seeing the tin plate, Einstein and his wife "laughed so much they thought they would die" ("ont tellement ri qu'ils croyaient en mourir") (see Maurice Solovine to Carl Seelig, 31 July 1955, SzZE Bibliothek, Hs. 304:1009). 192. To Conrad Habicht [Zurich, 17 December 1909] Ich bitte Sie sehr mir rasch den Titel des Notenheftes mit den alten Tänzen mitzuteilen[1] & auch den Verlag, aber an die Universitätsadresse,[2] weil ich das Heft zu Weihnachten meiner Frau geben will.[3] Schreiben Sie doch auch sonst ein wenig Ihrem A. E. AKS (Walter Habicht, Rodersdorf, Switzerland). [12 458]. The postcard is addressed "Herrn Konrad Habicht. Schiers Kt Graubünden.," and postmarked "Zürich 8 (Fluntern) 17.XII.09.-3." [1]Einstein may be referring to the music booklet mentioned in Doc. 177. [2]The physics institute of the University of Zurich was located at Rämistrasse 69. [3]Mileva played the piano (see Clark 1971, p. 30).