This small four-sided wooden block was known as a 'silent monitor' and was used by Robert Owen as a means of imposing discipline at his New Lanark Mills.

Robert Owen was strongly opposed to the use of corporal punishment, so in order to keep discipline at the New Lanark Mills, he devised his own unique system. The 'silent monitors' were hung next to each worker in the mills, with each side displaying a different colour. 'Bad' behaviour was represented by the colour black; 'indifferent' was represented by blue; 'good' by yellow; and 'excellent' by white. The superintendent was responsible for turning the monitors every day, according to how well or badly the worker had behaved. A daily note was then made of the conduct of the workers in the 'books of character' which were provided for each department in the mills.