|Madrid for kids|
A boat enters a chamber with gates at each end. To raise the boat, water is let into the chamber until it is the level of the water to be entered. When the water reaches that level the gates on the new elevation side are opened and you motor out.
A Lock is a short channel or a waterway divided into steps by watertight gates at either end. They form steps to move boats up or down hills. The first was invented by a Chinese engineer in the 10th century. Da Vinci developed the idea.
The Lock, 1824
Constable painted many idyllic English landscapes, often with people at work. His art style is Romantic and idealises nature. This is the landscape where Constable grew up. His dad owned a mill on the river.
The man pushes with his knee and arms on the lever to release the gate. The gate is in bad condition [but in reality had been repaired].