The streets, as Rollo called them, of open water, were full of boats, 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."