COMBINATION OF COLOURS.
Cut out a disc or circle of pasteboard, and cover it with paper half green and half black: cause the disc to be rapidly turned round, (like the shafts of a toy wind-mill,) and the colours will combine and produce white.
Cut out a disc or circle of pasteboard, and cover it with paper half green and half black: cause the disc to be rapidly turned round, (like the shafts of a toy wind-mill,) and the colours will combine and produce white.