322 DOCUMENT 283 SEPTEMBER 1911 langsam veränderbar ist. Beim Falle des isochorisch erwärmten Systemteiles hat man aber kein Mittel, um bei jedem Zustand diesen Teil zu verhindern, ein gewisses Energieintervall 8E zu verlassen. Auf so ein Intervall aber würden sich die exakten S und W-Werte beziehen müssen, derart, dass diese nicht nur von E, sondern auch von 5E abhängen. Natürlich kann das Gebiet, auf wel- ches man S und W bezieht, auch (nach kleineren Entropiewerten) unbegrenzt sein diese Wahl ist sogar manchmal vorteilhaft (osmotischer Druck), aber nicht prinzipiell wesentlich.- Denke an die Metalle! Da muss etwas Verständiges gefunden werden. Der jetzige Zustand ist nicht erträglich.[12] Anna und Vero danke ich für die freundlichen Zeilen. Seid alle drei bestens gegrüsst von Euerm Albert. Meine Frau legt einen Zeddel[13] bei. ALS (SzGB). Einstein/Besso 1972, 3 (E. 2). [7 250]. [1]The year is provided by the reference to the physics congress. [2]One of them is the preceding document. [3]Einstein was preparing a paper on specific heats for the Solvay Congress (see Doc. 269), which was held from 30 October until 3 November. See Einstein 1914a (Vol. 3, Doc. 26) for a published version of the lecture. [4]See Docs. 109, 182, and 187 for earlier discussions of the problem of absorption of radi- ation in quantum theory. [5]This hypothesis that collisions between electrons and atoms do not take place instanta- neously was first formulated in Sommerfeld 1911a as part of a theory of the emission of elec- tromagnetic radiation by accelerated or decelerated electrons. [6]Both the possibilty that the inhomogeneities in alloys are electron sources and the hy- pothesis that the mean free path of electrons in metals is inversely proportional to the density are mentioned by Besso in the preceding document. [7]Lampa 1911. It concerns the claim by Felix Ehrenhaft and others to have discovered sub- electronic charges (see the preceding document, in particular note 9, and Doc. 263, note 11). [8]This was pointed out in particular by Edmund Weiß, an Assistent in physics at the German University in Prague (see Doc. 263). [9]Karl Przibram (1878-1973), a Privatdozent in physics at the University of Vienna, had made measurements of the fundamental electric charge. Whereas Ehrenhaft had studied the mobility of charged metal particles in an electric field (see note 7), Przibram worked with va- por droplets, both with and without an external electric field (see, e.g., Przibram 1910). Przi- bram's measurements first seemed to confirm Ehrenhaft's results, but he remained cautious in his conclusions. In a remark made during the discussion following Jean Perrin's lecture at the Solvay Congress in the fall of 1911, the Viennese physicist Friedrich Hasenöhrl pointed out that Przibram had never adopted Ehrenhaft's views on the existence of subelectronic charges (see Perrin et al. 1914, p. 207, or Perrin et al. 1912, p. 25). [10]A reference to a dimensional argument, hinted at in the preceding document and devel- oped in Einstein 1909b (Vol. 2, Doc. 56), to find a connection between the elementary charge and Planck's constant. See Docs. 146, 153, and 163 for a discussion between Einstein and H. A. Lorentz on this point. [11]See Doc. 276 for Einstein's first mention of this example. [12]See the preceding document for Besso's thoughts on the electron theory of metals. [13]Swiss German for "Zettel."