He knew it was somewhere and he was going to find it.
Suddenly he paused by a certain willow tree, looking at it curiously.
"What is it ?" Hervey asked excitedly.
"Looks as if a jack-knife had been at work around here, huh?
Somebody's been making a willow whistle.

Look at this." Tom held up a little tube of moist willow bark, at the same time kicking some shavings at his feet.

"Looks as if they passed this point, anyway," he said.

"Ever make one of those willow whistles?
I've made dozens of them for tenderfeet.

If you make them the right way, they make a dickens of a loud noise.".