say, shan't we have to pay a lot for the
boat?"

"Yes," George assented mournfully; "but perhaps the man will let us
off cheap when he sees we couldn't help it. He looked a good-tempered
sort of chap. Come, let us set to work. Every minute it is taking us
further away."

They set steadily to work. The boat was a large and heavy one, and
their progress was by no means rapid.

"How thick it's getting!" George exclaimed suddenly.

"Aint it just!" Bill assented. "My eye, George, I can't see the
barges!"

Unobserved by them a fog had been steadily creeping up the river. They
were just at its edge when they made the discovery. Another two
minutes and it rolled thickly over them, and they could not see ten
yards away. They looked at each other in silent bewilderment.

"What's to be done, George?" Bill said at length in awe-struck tones.

"I don't know, Bill; I haven't an idea. It's no use rowing, that I
see, for we don't know which way the boat's head is pointing."

"Well, it can't be helped," Bill said philosophically. "I am going to
have a pipe. Oh, I say, aint my hands blistered!"

"All right, you can have your pipe, Bill, but keep your oar in your
hand to be ready to row."

"What for?" Bill demanded. "I thought you said it warn't no use
rowing!"

"No more it is, Bill; but we must look out for those big buoys. If the
tide were to sweep us against one of them we should capsize to a
certainty. That must have been a big steamer," he went on, as the boat
rolled suddenly. "It's lucky we were pretty well over towards the side
of the river, before the fog came on. Listen--there's another. I can
hear the beat of her engines. I have an idea, Bill!" he exclaimed
suddenly. "We know the steamers were passing to the left of us when
the fog came on. If we listen to their whistles and the sound of their
paddles, and then row to the right, we shall get to the bank at last."

"Yes, that's a good idea," Bill agreed, laying down the pipe he had
just lighted. "There's a whistle over there."

"Yes, and another the other way," George said, puzzled. "Why, how can
that be! Oh, I suppose one is coming up the river and one down, but
it's awfully confusing."

It was so, but by dint of listening intently the boys gained some idea
of the proper direction; but they could only row a few strokes at a
time, being obliged to stop continually to listen for fresh guidance.

Fortunately for them the fog lay low on the water, and the upper s