††††A lock is a section of river or canal between watertight gates.
It was invented in 983 AD by Qiao Wei-Yao, a Chinaman. A lock works by dividing sections of a river or canal into ascending or descending 'steps'. This means that craft can be taken up a gradient in stages, and there is no need for canals to wind around hilly obstacles. Prior to the development of the canal lock, boats often needed to be hauled over difficult patches. This frequently damaged the boat and resulted in lost cargo.
