The atomic heats of copper, silver and gold have been determined in the temperature interval 1.0° to 5.0° K. The measured values can be described adequately by a linear plus a cubic term in temperature. Any deviations from this relationship are explainable in terms of inaccuracies in the presently accepted helium vapor pressure-temperature scale. In fact, it is shown that the temperature scale corrections, necessary to correct the data to the simple law given above, essentially agree with temperature scale corrections suggested by other work. Values'of the coefficient of the linear term (electron heat capacity), and the Debye characteristic temperature have been derived and compared with several indirect determinations, as well as with other calorimetric data, where possible. The values of the electronic heat capacity determined in the work are consistently lower than those from previous work on copper and silver. 7 M.

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The atomic heats of vanadium, in the normal and superconducting states, have been determined from just above the transition temperature, r c =5.03°K, down to 1.1 °K. After corrections to the 1948 temperature scale had been made, the normal state atomic heat could be represented by C n = yT-{-(12/5)Tr i R(T/®) z , with 7= (9.26rfc0.03)X10-3 joule mole^1 deg^2 and 0 = 338±5°K. The entropy difference, S n~Ss , between the normal and superconducting states, extrapolated to 0°K, was found to vanish, in accordance with the third law of thermodynamics. The critical field values deduced from S n -S 8 gave #0=1310 oersteds; at higher temperatures they were in agreement with initial penetration fields previously reported.The most interesting result of this work was that below about .0.7T c the electronic contribution to the atomic heat of the metal in the superconducting state could be represented by an exponential expression of the form C es /yT c =ae~b Tc,T with a -9X1 and 6 = 1.50; such an exponential relation is consistent with a single-electron model of a superconductor involving a gap of the order of kT c per electron in the spectrum of available energy levels.

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An account is given of a simple, reliable, and generally applicable electrical means for accurately measuring and controlling the level of low boiling-point liquids. The sensitive elements exhibit at least a fivefold voltage difference for nitrogen and at least a five hundred-fold difference for helium depending on whether they are in the liquid or the vapor. Heat transfer characteristics for liquid nitrogen are also noted.