H FOR A CLEW.

Following the lead of Elmer, the tall lanky scout and the wiry Southern
boy quickly found themselves at the other end of the mill dam.

Lil Artha had cast his eyes about him as he cautiously made his way
along. He seemed to be figuring on what chance there might be for an
active chap like Nat Scott slipping on one of the wet and moss-covered
stones, to go tumbling down toward that suspicious black pool.

Not so Chatz Maxfield.

Apparently he had made up his mind from the start that this strange
vanishing of their comrade must have some connection with the mystery of
the old mill.

Did they not admit that three separate times people had tried to live
there in the dwelling that was part and parcel of the mill; and on every
occasion they had given it up as a bad job?

Why?

Well, it seemed to be understood that none of them could stand the
sights and sounds which had come to them while under that roof.

People might scoff at such things all they had a mind to, but surely it
seemed as if there must be _something_ in it.

At any rate, everyone of those three families believed the mill house
haunted. And for many years now, no one had had the nerve to occupy the
place.

And yet it had once been a paying venture, for the main road was only a
few hundred yards away from this lonely, forbidding-looking pond, where
the frogs grew so large and the red-marked "turkles," as Ty Collins
called them, were so saucy.

"Careful here!" warned Elmer, as they arrived at the runway, where in
times past the water was turned on when the mill was to be operated.

The boards were rotting and slimy, and if one made a slip he might get a
wet jacket in the sluice, where there was more or less running water.

Elmer held up a hand to hold his comrades back. He seemed to be down on
his hands and knees, as though examining something that had just caught
his attention.

"What is it?" asked Lil Artha.

"He came this way, all right, boys."

"Do you mean Nat?" questioned Chatz.

"Why, of course," replied the leader.

"How do you know?" continued Chatz.

"I've been following Nat's trail for miles," answered Elmer, "and sure I
ought to know what his footprint looks like. Here it is on this clay
just beside the sluice. Wait till I cross and see if he made the other
side all right."

"He must, because he ain't in the sluiceway," remarked the tall boy.

A minute later and Elmer, who had carefully crossed over, testing