Sherrington notes that the rotating lamp 'was set vertically in the axis of a rotating cylinder. This cylinder of turned brass was 78 mm. in diameter. In its side were cut three horizontal rows of rectangular windows tier above tier. The lamp though fixed in the axis of rotation of this revolving cylindrical screen was entirely free from all attachment to it.' (C.S. Sherrington, 'On Binocular Flicker and the Correlations of Activity of 'Corresponding' Retinal Points', Journal of Psychology 1 (1) (1904), p. 27.)