Artificial pitch‐bonded graphite is known to exhibit an extremely large variation of heat conductivity with temperature. It is both rigid and strong, and below 1°K its heat conductivity is exceptionally small. For these reasons we have found it to be an ideal support material for use within the adiabatic enclosure of a cryostat operated below 1°K. Furthermore, above liquid nitrogen temperature graphite is an excellent heat conductor, and when used in parallel with a lead heat switch, it proves unnecessary to admit exchange gas during the precool period. The graphite exhibits a strong pumping action for helium gas at low temperatures.