hing Brook would be full of water again, and we
could go back to the Smiling Pool as soon as we felt like it, and here
it is as bad as ever."

"Perhaps the trouble is just that some sticks and grass drifted down in
the water and filled up the hole I made; that must be the trouble," said
Jerry hopefully, as he hurried towards the dam.

First he carefully examined it from the Laughing Brook side. Then he
dived down under water on the other side. He was gone a long time, and
Billy Mink was just getting ready to dive to see what had become of him
when he came up again.

"What is the trouble?" cried Spotty the Turtle and Grandfather Frog and
Billy Mink and Little Joe Otter together. "Is the hole filled up with
stuff that has drifted in?"

Jerry shook his head, as he slowly climbed out of the water. "No," said
he. "No, it isn't filled with drift stuff brought down by the water. It
is filled with sticks and mud that somebody has put there. Somebody has
filled up the hole that I worked so hard to make yesterday, and it will
take me all day to open it up again."

Then Grandfather Frog and Spotty the Turtle and Billy Mink and Little
Joe Otter and Jerry Muskrat stared at one mother, and for a long time no
one said a word.

CHAPTER XXI: Jerry Muskrat Keeps Watch

"The way in which to find things out,
And what goes on all round about,
Is just to keep my two eyes peeled
And two ears all the time unsealed."

So said Jerry Muskrat, as he settled himself comfortably on one end
of the new dam across the Laughing Brook deep in the Green Forest and
watched the dark shadows creep farther and farther out into the strange
pond made by the new dam.

"I'm going to find out who it is that built this dam, and who it is that
filled the hole I made in it! I'm going to find out if I have to move up
here and live all summer!" The way in which Jerry said this and snapped
his teeth together showed that he meant just what he said.

You see Jerry had spent another long, weary day opening the hole in the
dam once more, only to have it closed again while he slept. That had
been enough for Jerry. He hadn't tried again. Instead he had made up
his mind that he would find out who was playing such a trick on him. He
would just watch until they came, and then if they were not bigger than
he, or there were not too many of them, he would--well, the way Jerry
gritted and clashed those sharp teeth of his sounded as if he meant to
do somethin