r them at the station, and in a
few minutes they had reached the mineowner's house.

Charles Leatham was a man of about five-and-thirty, tall, broad, and
of muscular build. He had a strong, clean-shaven face, a kindly though
direct manner, and there was about him a SUGGESTION of decision and
efficiency which inspired the confidence of those with whom he came in
contact.

"This is very jolly," he greeted them. "How are you, old man? Glad
to meet you, Hilliard. This is better than the lonely evening I was
expecting."

They went into dinner presently, but it was not until the meal was over
and they were stretched in basket chairs on the terrace in the cool
evening air that Merriman reverted to the subject which had brought them
together.

"I'm afraid," he began, "it's only now when I am right up against it
that I realize what appalling cheek we show in coming to you like this,
and when you hear what we have in our minds, I'm afraid you will think
so too. As a matter of fact, we've accidentally got hold of information
that a criminal organization of some kind is in operation. For various
reasons our hands are tied about going to the police, so we're trying to
play the detectives ourselves, and now we're up against a difficulty
we don't see our way through. We thought if we could interest you
sufficiently to induce you to join us, we might devise a scheme."

Amazement had been growing on Leatham's face while Merriman was
speaking.

"Sounds like the New Arabian Nights!" he exclaimed. "You're not by any
chance pulling my leg?"

Merriman reassured him.

"The thing's really a bit serious," he continued. "If what we suspect is
going on, the parties concerned won't be squeamish about the means
they adopt to keep their secret. I imagine they'd have a short way with
meddlers."

Leatham's expression of astonishment did not decrease, but "By Jove!"
was all he said.

"For that reason we can only tell you about it in confidence."

Merriman paused and glanced questioningly at the other, who nodded
without replying.

"It began when I was cycling from Bayonne to Bordeaux," Merriman went
on, and he told his host about his visit to the clearing, his voyage of
discovery with Hilliard and what they had learned in France, their trip
to Hull, the Ferriby depot and their adventures thereat, ending up by
explaining their hollow pit-prop idea, and the difficulty with which
they found themselves faced.

Leatham heard the story wit