“I’ll just see what this fellow has been eating,” said Lew.  “Maybe we can find out what sort of bait to use.”  He opened his knife and slit the fish’s belly.  “Crabs!” he cried, as his knife blade turned up the remains of a crayfish.  “Now we know what they want.”

Soon Charley had a good bed of coals.  Lew, meantime, cleaned the fish.  Quickly it was cooked and eaten and the dishes washed.  By this time it was altogether dark.

“Now we’ll get some crabs for to-morrow,” said Lew.

“Wonder how we can catch them?” queried Charley.

“What we need is a little dip-net.  With that and the flash-light we could get a peck of them.  These little streams are full of them.”

“Let’s try scooping them with a coffee-pot.  The lid comes off.  If we are careful, I believe it will answer.”

They took the lid off of the pot, and stepping to the brook turned the beam from their flash-light on the bottom of the run.  The scene was fascinating.  Feeling secure in the darkness, the living creatures in the brook had ventured abroad freely.  Where the bright light of the sun would have disclosed only stones and sand, the little beam from the search-light revealed a myriad of moving shapes.  Little minnows moved about in schools.  Salamanders, large and small, crawled about among the rocks.  Occasional trout were visible, lurking in the deeper holes, lying as motionless as sticks, or moving their tails slowly.  Eels lay on the sandy spots.  And lying still or crawling slowly among the stones were many crayfish.  The water seemed to be filled with living objects.

“Gee whiz!” whispered Charley.  “It’s like going to an aquarium and looking at the fish in glass cages.  I never dreamed a brook could be so interesting.”

With the utmost caution they moved along the bank of the run, looking for crayfish of suitable size.  Whenever they found one, Charley focused the flash-light on it, moving the beam so as to dazzle the creature and keep the space behind it in darkness.  And Lew would slip the coffee-pot into the water and move it cautiously up to the crayfish, ready for a final, quick scoop.  Sometimes he was successful and sometimes the intended victim escaped.  Always the click of the metal pot against the stony bottom sent the little creatures in the water scurrying for cover.  A second after Lew tried for the crayfish not a living thing was visible.  So it was necessary to move on along the stream.  From spot to spot the two boys proceeded, now getting a good bait, now missing one, but ever keenly enjoying the wonderful glimpses of the life in the brook.  So they continued until they had a goodly number of crayfish.

“I believe that’s enough,” said Lew.  “Let’s get back to camp.  The fellows will be at their instruments at nine, ready to talk to us.”  He glanced at his watch.  “I had no idea,” he cried, “that it was so late.  It’s almost nine now.  We’ll have to hurry.”