Church over, he dashed off to examine the ditch. Yes, there was his grotto—he could see it from afar. On reaching the place, the first thing that caught his eye was a long, snake-like something lying half hidden in the rank grass. He picked it up. It was a piece of rubber tubing about three yards long.
“That must be what the man dropped when I sneezed,” said Danny. “I expect he was so worried with my biting his hand that he forgot to pick it up!”
The detective next turned his attention to the ditch. Yes, there were footmarks in the soft mud. And they were the very same that he had drawn a sketch of in his book that day he saw the stranger with the bicycle! There was a kind of dented, flattened place, as if someone had been lying in the ditch. Sticking out of the bank, half hidden by the rank grass, was an old moss-grown drain pipe. Putting his lips to it, Danny spoke a few words. His voice sounded hollow. He slipped the tubing down into it, and put the end to his ear.
“Some telephone!” he said, and fairly wriggled with delight. “So that’s what the chap was doing last night! The question is, who was he talking to, and what kind of a place does this pipe lead to?”
Search as he might he could find no sign of a cave or any hiding-place in the bank.
“It must be fairly deep,” he said, “or they wouldn’t want three yards of tubing.”
He poked a stone through the pipe, and heard it rattle down on to what sounded like a stone floor some way below. Then he sat up and considered. They weren’t just common tramps or poachers, these people he was after, for they owned a car. They were evidently afraid the police were on the lookout for them, or they would not have changed the number board and worn false beards!
“There is some connection between this drain-pipe telephone affair and the mill pond, and I mean to discover what it is!” said Danny the Detective.
After making his puzzling discovery of “the drain-pipe telephone” as he called it, Danny ran off to make his inspection of the mysterious pond. Running his eyes quickly over the bank he soon saw a clue that to the ordinary person would have meant nothing, but which revealed something very important to the “Detective.” On the dusty bank of the pond there was a wet patch, as if something or someone had come up out of the water and stood and dripped for a moment!
The morning shadows had not yet moved away from the spot and allowed the hot July sun to dry the ground. Examining the wet patch more closely, Danny saw that there was duck-weed on it—the same stuff that dotted the surface of the pond. There was also some black mud—just the kind of slime one would expect to coat the bottom of the pool.