sked Mark,
greatly excited.

"Who he is, and how he got there, are more than I know," answered
"Captain Li." "What he is doing, is waiting to be taken off. The men on
the tug sighted him just before you came on deck, and sung out to me to
send a boat for him. It's a mercy we didn't come along an hour sooner,
or we never would have seen him through the mist."

"You mean we would have missed him," said Mark, who, even upon so
serious an occasion, could not resist the temptation to make a pun.

By this time the boat had rescued the man from his unpleasant position,
and was returning with him on board. Before it reached the schooner
Mark rushed down into the cabin and called to his parents and Ruth to
hurry on deck. As they were already up and nearly dressed, they did so,
and reached it in time to see the stranger helped from the boat and up
the side of the vessel.

He was so exhausted that he was taken into the cabin, rolled in warm
blankets, and given restoratives and hot drinks before he was
questioned in regard to his adventure.

Meantime the schooner was again slipping rapidly down the broad river,
and Mark, who remained on deck with his father, questioned him about
the "river's breath," as he called the clouds of steam that arose from
it.

"That's exactly what it is, the 'river's breath,'" said Mr. Elmer.
"Warm air is lighter than cold, and consequently always rises; and the
warm, damp air rising from the surface of the river into the cold air
above is condensed into vapor, just as your warm, damp breath is at
this very moment."

"But I should think the water would be cold with all that ice floating
in it," said Mark.

"It would seem cold if we were surrounded by the air of a hot summer
day," answered his father; "but being of a much higher temperature than
the air above it, it would seem quite warm to you now if you should put
your bare hand into it. We can only say that a thing is warm by
comparing it with something that is colder, or cold by comparison with
that which is warmer."

When Mark and his father went down to breakfast they found the rescued
man still wrapped in blankets, but talking in a faint voice to the
captain; and at the table the latter told the Elmers what he had
learned from him.

His name was Jan Jansen, and he was a Swede, but had served for several
years in the United States navy. On being discharged from it he had
made his way to New Sweden, in the northern part of Maine; but, a