going and coming, and of lighters and wherries, with a steamer now and then shooting along among them, or a large vessel slowly coming up or going down by means of its sails.

"This is the way down the river," repeated Mr. George. "The ships have come up as far as here; but they cannot go any farther, on account of the bridge. Look above the bridge, and you will see that there are no ships." So Rollo and Mr. George turned round to look up the river. They could only catch an occasional glimpse of the river through casual openings in the stream of carts, carriages, vans, cabs, wagons, and omnibuses that were incessantly rolling on in opposite streams along the roadway of the bridge. Although the view was thus obstructed, they could easily see there were no

ships above the bridge that they were standing on. There were, however, several other bridges farther up, with a great many boats passing to and fro among them; and, here and there, there appeared a long and sharp-built little steamer, gliding swiftly through the water. These steamers were painted black, and they poured forth volumes of smoke so dark and dense from their funnels as quite to fill the air, and make the whole prospect in that direction exceedingly murky and obscure.

"Let us go over to the other side of the bridge," said Rollo.

"Not yet," said Mr. George; "but you see that there is no shipping above the bridge. Vessels could not go up above the bridge, in fact. They could not go up, for the masts are too long to pass under the arches."

"They might have a draw in the middle of the bridge," said Rollo.

"No," said Mr. George. "A draw will not answer, except in cases where there is only a moderate degree of passing over a bridge, so as to allow of an interruption for a little time without 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 direction which Mr. George indicated; and there he saw upon the bank of the river, a little below the Custom House,

rising above the other buildings in that quarter of the town, a large, square edifice, with turrets at the corners. This building was surrounded with other edifices of a castellated form, which gave the whole the appearance of an extended fortress.

"That," said Mr. George, "is the famous Tower of London."

"What is it famous for?" said Rollo.

"I can't stop to tell you about it now," said Mr. George. "It was built originally as a sort of fort to defend the city. You see, the place where the Tower stands was formerly the lower corner of the city; and there was a wall, beginning at the Tower, and running back all around the city, and so down to the water again at the upper end of it. Do you see St. Paul's?" added Mr. George, turning half round and pointing.

"Yes," said Rollo; "but it is pretty smoky."

"You can see," said Mr. George, "from the position of St. Paul's, where the old wall went. It passed some distance back from St. Paul's, and came down to the water some distance above it. All within this wall was the old city of London; and the Tower was built at the lower corner of it to defend it.

"Do you see any reason," continued Mr. George, "why they should place the Tower at

the lower end, rather than at the upper end, of the city?"

"No," said Rollo, "I do not see any reason in particular."

"The reason was," said Mr. George, "that what they had reason to guard the city against was the danger of an attack from enemies coming up the river in ships from the sea; and so they placed the Tower below the city, in order to intercept them. But now the city has spread and extended down the river far below the Tower, and back far beyond the old wall; so that the Tower is, at the present time, in the midst of an immense region of streets and warehouses, and it is no longer of any use as a fortification. It is too high up."

"What do they use it for, then?" said Rollo.

"It is used by the government," said Mr. George, "as a sort of strong box, to keep curiosities, treasures, and valuables of all sorts in, and any thing else, in fact, which they wish to have in safe and secure custody. They keep what are called state prisoners there."

"Can we go in the Tower," said Rollo, "and see all these things?"

"Yes," said Mr. George, "we can see the treasures and curiosities; but I believe there are no prisoners there now."

Just then Rollo heard a rapping sound upon the stone of the sidewalk near him. He looked round to see what it was. There was a blind man coming along. He had a stick in his hand, which seemed to be armed at the lower end with a little ferule of iron. With this iron the blind man kept up a continual rapping on the flagstones as he slowly advanced. The iron produced a sharp and ringing sound, which easily made itself heard above the thundering din of the carriages and vans that were rolling incessantly over the bridge, and served as a warning to the foot passengers on the sidewalk that a blind man was coming. Every one hearing this rapping looked up to see what it meant; and, perceiving that it was a blind man, they moved to one side and the other to make way for him. Thus, though the sidewalk