An experimental high vacuum furnace with a platinum‐rhodium resistance heating element is described; it is operable also in oxygen or other gases up to pressures of at least 10−3
mm Hg. The furnace is assembled from readily obtainable equipment, and knife‐edge vacuum seals are used throughout. The uniform hot zone is approximately 1
in. in diameter and 2 in. long. The power required for 1400°C, the maximum safe operating temperature, is about 1 kw; at this temperature the pressure is ∼10−8
mm Hg. This furnace is suitable for electrical conduction studies as well as for heat treatment, etc.