A compact gas high pressure cell for measuring the optical properties of solids at low temperatures under pressures up to 10 kilobars is described. Using helium gas as the pressure‐transmitting medium, the pressure is purely hydrostatic at 78°K and nearly hydrostatic at 7–12°K. Techniques are discussed for sealing windows of sapphire for optical studies, of beryllium for x irradiation, and dummy windows for electrical connections. A cryostat which can be accommodated in most recording spectrophotometers is also described.