his visit to the sawmill
and his discovery of the alteration in the number of the lorry. He gave
the facts exactly as they had occurred, with the single exception that
he made no mention of his meeting with Madeleine Coburn.

"And what happened?" asked Drake, another of the men, when he had
finished.

"Nothing more happened," Merriman returned. "The manager came and gave
me some petrol, and I cleared out. The point is, why should that number
plate have been changed?"

Jelfs fixed his eyes on the speaker, and gave the little sidelong
nod which indicated to the others that another joke was about to be
perpetrated.

"You say," he asked impressively, "that the lorry was at first 4 and
then 3. Are you sure you haven't made a mistake of 41?"

"How do you mean?"

"I mean that it's a common enough phenomenon for a No. 4 lorry to
change, after lunch, let us say, into No. 44. Are you sure it wasn't
44?"

Merriman joined in the laughter against him.

"It wasn't forty-anything, you old blighter," he said good-humoredly.
"It was 4 on the road, and 3 at the mill, and I'm as sure of it as that
you're an amiable imbecile."

"Inconclusive," murmured Jelfs, "entirely inconclusive. But," he
persisted, "you must not hold back material evidence. You haven't told
us yet what you had at lunch."

"Oh, stow it, Jelfs," said Hilliard, a thin-faced, eager-looking young
man who had not yet spoken. "Have you no theory yourself, Merriman?"

"None. I was completely puzzled. I would have mentioned it before, only
it seemed to be making a mountain out of nothing."

"I think Jelfs' question should be answered, you know," Drake said
critically, and after some more good-natured chaff the subject dropped.

Shortly after one of the men had to leave to catch his train, and the
party broke up. As they left the building Merriman found Hilliard at his
elbow.

"Are you walking?" the latter queried. "If so I'll come along."

Claud Hilliard was the son of a clergyman in the Midlands, a keen, not
to say brilliant student who had passed through both school and college
with distinction, and was already at the age of eight-and-twenty making
a name for himself on the headquarters staff of the Customs Department.
His thin, eager face, with its hooked nose, pale blue eyes and light,
rather untidy-looking hair, formed a true index of his nimble, somewhat
speculative mind. What he did, he did with his might. He was keenly
interested in whatever he took