The electrically heated bit described is used for boring sounding holes in glaciers. The-bit, which melts its way downward, is a bare high-resistance wire, helically wound and tapering to a point. Appropriate contacts and relays provide protection when encountering rocks or air spaces. The average drilling speed of the bit was 20 to 25 m/hr for an average hole diameter between 60 and 80 mm. The deepest boring was stopped by bedrock 195 m below the surface of the glacier. Theoretical and practical aspects of the development and use of this apparatus are discussed.