D O C . 1 2 M A R C H 1 9 1 9 1 1 dynamics. In this regard I worked on Maxwell’s distribution law and, together with Prof. Sommerfeld, on the theory of monatomic gases. This development was in- terrupted by a return to the electrodynamic problem of my dissertation from a new point of view. I was able to calculate the spectrum of the eigenfrequencies of a coil in a very simple way, relatively speaking. With this paper I took my Habilitation degree. The resumption of my inquiry into statistical problems was brought to an end by the outbreak of war. Throughout the duration of the war my military duties left me very little time and energy for scientific analyses. Only toward the end of the war did my situation improve I addressed the problem of the structure of atom- ic nuclei of hydrogen cores and electrons according to quantum theory. These ef- forts arose from a paper on “an inverted Bohrian model of the atom”. —A list of my publications is enclosed. This hindrance by the war of my scientific activity is now, after the end of the war, joined by another, if lesser hindrance, upon my assumption of an assistantship, which I cannot avoid owing to my pecuniary situation. My current income from this position totals, with the cost-of-living allowance, about 2500 marks, an amount which meanwhile has proven inadequate at the present time. Since I am not in a position to supplement this in the long run with money from private sources, a stipend in an amount above that of an assistant’s salary would free me from the ob- ligations of the assistantship and from the burden of financial worries. I intend primarily to take up again the theory of monatomic gases, from the per- spective of the quantization of the collision process. This would lead to the question of treating nonperiodic processes according to quantum theory and, in connection with this, to the problem of the nature of continuously distributed X-ray spectra. In addition, I intend to continue the analyses on the feasibility of nuclear models ac- cording to quantum theory, which has thus far referred to the first elements of the periodic system, with a view toward the radioactive end of the periodic system. For these analyses I take the liberty of applying to you respectfully for approval of a stipend, if possible at a level above that of my present salary as assistant. Respectfully and sincerely, Dr. Wilh[elm] Lenz Institute for Theoretical Physics of the University of Munich Secretary’s note at head “Application by Dr. W. Lenz.” 12. From Arnold Sommerfeld Munich, 25 March 1919 Dear Einstein, I am launching a two-pronged attack on you.