Many of the lines might as easily have been written of Rotterdam as of Brooklyn:-- The sailors at work in the rigging or out astride the spars, The round masts, the swinging motion of the hulls, the slender serpentine pennants, The large and small steamers in motion, the pilots in their pilot-houses, The white wake left by the passage, the quick tremulous whirl of the wheels, The flags of all nations, the falling of them at sunset, The scallop-edged waves in the twilight, the ladled cups, the frolicsome crests and glistening, The stretch afar growing dimmer and dimmer, the grey walls of the granite storehouses by the docks, On the river the shadowy group, the big steam-tug closely flank'd on each side by the barges, the hay-boat, the belated lighter, On the neighbouring shore the fires from the foundry chimneys burning high and glaringly into the night, Casting their flicker of black contrasted with wild red and yellow light over the tops of the houses, and down into the clefts of streets.
There is of course nothing odd in the description of one harbour fitting another, for harbours have no one nationality but all.

Whitman was not otherwise very strong upon Holland.

He writes in "Salut au Monde" of "the sail and steamships of the world" which in his mind's eye he beholds as they Wait steam'd up ready to start in the ports of Australia, Wait at Liverpool, Glasgow, Dublin, Marseilles, Lisbon, Naples, Hamburg, Bremen, Bordeaux, The Hague, Copenhagen.
It is not easy for one of the "sail or steamships of the world" to wait steamed up at The Hague; because The Hague has no harbour except for small craft and barges.

Shall we assume, with great charity, that Walt feared that the word Rotterdam might impair his rhythm?
Not only big shipping: I think one may see barges and canal boats in greater variety at Rotterdam than anywhere else.

One curious thing to be noticed as they lie at rest in the canals is the absence of men.