Calculation of the westward drift of the earth's magnetic field for epoch 1960 by the method of least-square fit. The drifts of he magnetic potential and of the radial magnetic field are calculated at the surface of the earth and at the surface of the earth's fluid core; the values are shown to depend on the distance from the center of the earth. Drifts calculated for different components of the geomagnetic field are not in agreement, nor are the drifts of the nondipole components about the geomagnetic axis. This suggests that other types of motion besides simple westward drift are important. The value for the drift of the radial magnetic field at the earth's core (0.155 deg/yr westward) should provide the best estimate of the drift of the fluid at the surface of the core.
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