t any great inconvenience.
But this bridge, you see, is perfectly thronged all the time with
continued streams of foot passengers and carriages. If a draw were to be
opened in this bridge for only ten minutes, to allow a vessel to go
through, there would be such a jam on both sides that it would take all
day to disentangle it."

"I don't see how the little steamers get through under the bridges,"
said Rollo. "The smoke-pipes are higher than the arches."

"Yes," said Mr. George, "they are. But I will show you how they manage
that by and by. There is something very curious about that. Now let us
look down the river again."

So Rollo turned round with Mr. George, and they both looked down the
river. They saw on the left hand of the river--that is, on the London
side, the side towards which they were going--a great steamboat landing,
with several steamboats lying near it.

"That is where the steamboats lie," said Mr. George, "that go down to
the mouth of the river, and across the sea to France, Holland, and
Germany."

"I should like to go in one of them," said Rollo.

"Do you see that large building just below the steamboat landing,
fronting the river?"

"Yes," said Rollo; "what is it?"

"It is the Custom House," said Mr. George. "Every ship that comes into
the Thames from foreign countries has to send her manifest there and pay
the duties."

"What is a manifest?" said Rollo.

"It is a list, or schedule," said Mr. George, "of every thing there is
contained in the cargo. The officers of the Custom House make a
calculation, by this manifest, of the amount of duties that are to be
paid to the government for the cargo, and the owners of the ship have to
pay it before they can land their goods."

"Can we go into the Custom House and see it?" said Rollo.

"Yes," said Mr. George. "I am sure it must be open to the public,
because all sorts of persons must have occasion to go there continually,
to transact business; but I do not suppose there would be much to see
inside. There would be a great many tables and desks, and a great many
clerks and monstrous big account books, and multitudes of people coming
and going continually; but that would be all."

"I should like to go and see them," said Rollo.

"Well," said Mr. George, "perhaps we will look in some time when we are
going by on our way to the Tower or to the Tunnel. But now look down
just below the Custom House and see the Tower."

Rollo looked in the directio