Magnetic and equivalent-width data (red dots: AAT; blue squares: CFHT) phased with Eq. (5), repeated over two rotational periods. Lower two panels: magnetic data with their residuals to the best-fit cosine curve. Panels 3, 4 and 5 from bottom: equivalent widths of the Si iii 4575, He i 4471 and Al iii 5696 lines with a best-fit sinusoid superposed. Note the opposite behavior of the different lines. Top: C iv 1540 equivalent width fifteen years earlier. The dashed curve is a suggested double sine wave, with arbitrary amplitude, and phased according to what is observed in other similar magnetic stars.