This electrostaticion source operates as a cold cathode device. It produces a beam of energetic positive ions of, for example, 100 μ A/cm 2 at a pressure of 5×10 −4 Torr when operated at an anode potential of 10 kV. The ion beam is reasonably well collimated and the ions have a broad energy spectrum. It is therefore most suitable for sputter-ion etching of metallic and nonmetallic specimens for electron microscopy. It is relatively simple to construct and entirely reliable in operation. A number of optical and scanning electron micrographs of etched surfaces obtained with this source are given.