Replica of Samuel Morland's arithmetic machine
This large-scale replica of the Morland calculator was used by the BBC in the programme 'What the Tudors and Stuarts Did for Us', televised in 2002. It was used to demonstrate how the device works. A stylus was used to turn the major dials. If one moved from 9 to 0 it engaged the small wheel above it, which then showed how much should be carried to the next wheel on the left. Mechanical calculators have been used in schools to assist with understanding the basic arithmetical processes since the mid 20th century.