The Specific Heat of Pure Iron at Low Temperatures

Abstract

Specific‐heat measurements of iron of 99.94 percent purity were determined throughout the temperature range 52° to 298°K. These measurements were undertaken because of the five sets of determinations in this region previously recorded in the literature are in disagreement, with the exception of those of Eucken and Werth and of Simon and Swain, although even these differ on an average of 1.8 percent. Present results are considered accurate on the average to within 0.3 percent, and they confirm the work of the investigators just mentioned rather than that of Rodebush and Michalek and of Griffiths and Griffiths. The entropy of iron was computed as S_298.16 = 6.49±0.03 cal./deg. (gram atom), of which only 4×10⁻⁴ is extrapolation below 1°K.