D O C U M E N T 4 2 9 D E C E M B E R 1 9 2 6 4 0 5 429. From Walther Meißner [Friedenau, Berlin,] 7 December 1926 Dear Professor, Of course it will be a special pleasure for me to participate in the verification of the gas degeneracy theories as you comprehend them.[1] I place myself entirely at your disposal in this regard. You will perhaps only need to have some patience be- cause, due to installation work for the new low-temperature laboratory,[2] I can usu- ally only start to work properly after 4 o’clock. My measurements of the specific heat of gaseous helium at the temperature of liquid helium, which are under way, might also be useful. What you wrote to me about Fermi’s theory, which I have now also briefly had a look at, was very interesting.[3] A question occurred to me about whether, at the zero-point energy, the difference between the generation heats u + pv at high and low pressures of 15° atm would obtain the wrong sign, a difference that, according to your theory, is already smaller than according to the result of the helium lique- faction. However, I cannot assess this without closer study. With cordial thanks for your kind note, yours sincerely, W. Meißner