Houdeng, a small village close to the city of La Louvière in Belgium is known for it's two water elevators.

The chanels to relay different rivers had a too high difference in level on that place and the elvators where built to bring boats from the top to the bottom and back.

The elder one of this two elevators, shown here, works with water only. The two bassins where the boats take place are actuated by hydraulic pistons on which they move up and down. The both pistons are connected by a tube and a valve that is opened more or less to control the speed of the movement. If the weight in one of the both bassins is bigger then in the other, the pressure on it's piston presses the water to into the other piston which makes that bassin move upwards.
The trick is to fill the bassin on the top with more water to get a bigger weight then the one at the bottom.

Note that the only parts that are mechanical are hand operated valves to control the water displacement between the both pistons and the valves to control the water level in the bassins.
There is on guy in the bottom to open those valves and the doors of the bassins and another one on the top to do the same.

A very smart construction using simple physical laws such as weight scale principles and water displacement rules determined once by Archimedes.

More about it here : http://users.swing.be/ccocksta/ccmarche.htm

I will post the other elevator tomorrow.