Time variation of sample position measured for a sub-millimeter-sized sample of polyethylene-1 (in Table 1). The sample was released at t = 0. The values of x were determined by a scale that was attached along the x-axis. The images of the scale and the sample were recorded by a high-vision camera. A line x = xR denotes the position where B = 0. The measured distribution of magnetic field along the x-axis is shown in the figure (Hisayoshi et al., 2011).