Several inorganic substances have been examined by electron microscope and selected area electron diffraction techniques. Large crystals of sodium chloride and potassium chloride break up into many smaller crystals of the same substances. Ammonium chloride evaporates, and nitron nitrate appears merely to melt. Reduction to metal was found for silver chloride, silver nitrate, lead carbonate, and cupric oxide. Only morphological changes were observed on bombardment of silver sulfate, lead oxide, lead chloride, and gold chloride. Hydrous ferric oxide and aluminum oxide were converted to crystalline forms which could not be identified by electron diffraction.