Dr. Thomas presided, with 58 members and visitors present. Dr. Michael Fleischer of the U. S. Geological Survey addressed the society on “The Role of Hydrogen in Minerals.” Pressure-temperature data are obtained by carefully controlled heating methods and the results are plotted. An x-ray analysis will reveal the possibility of the water being either a part of the structural lattice or merely adsorbed. There is a great variance in the amount of energy that binds the hydroxyl to the crystal lattice. In ter layered water will cause minerals such as bentonite to expand along the c-axis on heating, without changing the lattice.