of it down into the mud, and
that made more bubbles come up.

"They are bubbles of air," said Jonas.

"But how comes the air down there," said Rollo, "under the water?"

"I don't know," said Jonas; "and besides I must not stay and talk here;
I must go back to my work. I will talk to you about it when you come
back." So Jonas returned to his work, and Rollo went to the house again
after the lantern.

When he came back to the brook, he found that he could not make any more
bubbles come up; but instead of that, his attention was attracted by
some curiously colored pebbles near the shore. He put his hand down into
the water, and took up two or three of them. He thought they were
beautiful. Then he took his dipper, which had, all this time, been lying
forgotten by the side of a log, on the shore, and walked along--the
dipper full of raspberries in one hand, the lantern in the other, and
his bright and beautiful pebbles in his pocket.

Rollo followed the path along the banks of the brook under the trees,
until at length he came out to the open ground where Jonas was at work.
There was a broad meadow, or rather marsh, which extended back to some
distance from the brook, and beyond it the land rose to a hill. Just at
the foot of this high land, at the side of the marsh farthest from the
brook, was a pool of water, which had been standing there all summer,
and was half full of green slime. Jonas had been at work, cutting a
canal, or drain, from the bank of the brook back to this pool, in order
to let the water off. The last time that Rollo had seen the marsh, it
had been very wet, so wet that it was impossible for him to walk over
it; it was then full of green moss, and sedgy grass, and black mire,
with tufts of flags, brakes, and cranberry-bushes, here and there all
over it. If any person stepped upon it, he would immediately sink in,
except in some places, where the surface was firm enough to bear one up,
and there the ground quivered and fluctuated under the tread, for some
distance around, showing that it was all soft below.

When Rollo came out in view of the marsh, he saw Jonas at work away off
in the middle of it, not very far from the pool. So he called out to him
in a very loud voice,

"Jo--nas!----hal--lo!"[A]

[Footnote A: See Frontispiece.]

Jonas, who had been stooping down at his work, rose up at hearing this
call, and replied to Rollo.

Rollo asked him how he should get across to him.

"O, walk righ