By means of solution calorimetry in a molten oxide solvent of composition 2PbO·B2O3 at 692±2°C, the enthalpy of transformation of tetragonal to hexagonal germania was found to be +5·17±0.25 kcal/mole, and that of hexagonal germania to glass, +3·7±0·6 kcal/mole. The heat content increment between room temperature room temperature and the calorimetric temperature. H966-H295. of the tetragonal form was measured by "transposed-temperature" drop calorimetry in order to refer these data to room temperature. The enthalpies and calculated entropies for the transformations are discussed, and compared with the corresponding values for silica.