Abstract
Two sets of widely refered data on the equilibrium moisture content of wood, one by U.S.D.A., Forest Products Laboratory and the other by R. Keylwerth, were examined for the temperature dependency by applying the Clapeyron-Clausius equation. The apparent differential heat of sorption and the related quantities were compared with the literature values obtained by calorimetry. The difference was found to be too great to be neglected for approximation. The effect of sorption hysteresis upon the apparent differential heat was also estimated from the data in literature, and the result was comparable in its extent to the above mentioned discrepancy. On the contrary, the data of Stamm and Loughborough obtained by their “oscillating desorption” method were proved to be in accordance with the calorimetric data.
