Kelvin's first tide predicting machine, 1872

Detail. Lord Kelvin (1824-1907) designed this machine to predict the tide patterns in harbours. It has ten dials which are are set with the oceanographic and astronomical data of the harbour. On cranking the handle, the machine calculates the harbour's tide patterns for up to a year in only four hours. A machine like this was used in central India for many years to calculate all the tidal patterns for the country.