Every bulwark has a washing tray that can be fixed or detached in a moment.

"It's a fine day, let us kill something," says the Englishman; "Here's an odd moment, let us wash something," says the Dutch vrouw.
In some of the Rotterdam canals the barges are so packed that they lie touching each other, with their burgees flying all in the same direction, as the vanes of St.Sepulchre's in Holborn cannot do.

How they ever get disentangled again and proceed on their free way to their distant homes is a mystery.

But in the shipping world incredible things can happen at night.
One does not, perhaps, in Rotterdam realise all at once that every drop of water in these city-bound canals is related to every other drop of water in the other canals of Holland, however distant.

From any one canal you can reach in time every other.