It was considered dÃ©classÃ© to refer to one's own townhouses, estates or villas (or those of friends) as mansions and modern etiquette books still advise that the terms house, big house or great house be used instead.
Waste weir. A waste weir on a navigable canal is a slatted gate on each canal level or pound, to remove excess water and to drain the canal for repairs or for the winter shutdown.
The canal has three sets of locks, (waterfilled chambers) which raise and lower ships from one level to another. The locks were built in pairs to allow ships to pass through in both directions at the same time. Each lock has a usable length of 300 metres, a width of 34 metres, and a depth of about 20 metres.