The design and construction of a Q-Machine is discussed and its theory of operation is outlined. The Q-Machine to be described measures the mechanical resistance and reactance of small mechanical damping members in a frequency range near 100 cycles per second. The effect of the damping member under test on the resonant frequency and sharpness of resonance of a relatively high-Q, mechanical, tuned circuit is obtained by observing the amplitude of vibration of the mass in the Q-Machine's tuned circuit with capacitive pick-up probes. From this data, resistance and reactance can readily be computed. Application of the Q-Machine to the design of electromechanical transducers and to the testing of the properties of audio damping materials is discussed.