A calorimeter is described for routine measurements of specific heats in the temperature region of liquid hydrogen and liquid helium. It is designed so that samples can be interchanged without disturbing the calibration of the thermometer, or the water equivalent of the calorimeter. The calorimeter has been used to measure the specific heat of manganese from 16° to 22° K. It was found that the atomic heat of this metal is given by the formula[Formula: see text]