Abstract
Precise measurement of the attracting force between two polarized spheres inside an electric field indicates that the rotation of one sphere along the axis perpendicular to the electric field reduces the attracting force between them. The important difference between the experimental results and the existing theory indicated that this reduction is due to several factors. In addition to the reduction of polarization due to the free surface charges, the rotation may also weaken the local field near the rotating sphere, making the main contribution to the reduction of the attracting force. Moreover, the experiment also suggests that the polarization due to the molecular polarizability cannot be ignored.