t was
not only smaller and more compact, but it was deserted at intervals.
If he could not succeed at the syndicate's enclosure he would have no
chance at the larger building.

It was true he had already searched it without result, but he was not
then specially looking for a cellar, and with a more definite objective
he might have better luck. He decided that if Benson went up to Hull
that night he would have another try.

He took an afternoon train to Ferriby, and walking back towards the
depot, took cover in the same place that he had previously used. There,
sheltered by a hedge, he watched for the manager's appearance.

The weather had, from the inspector's point of view, changed for the
worse. The sunny days had gone, and the sky was overladen with clouds. A
cold wind blew in gustily from the south-east, bringing a damp fog which
threatened every minute to turn to rain, and flecking the lead-colored
waters of the estuary with spots of white. Willis shivered and drew up
his collar higher round his ears as he crouched behind the wet bushes.

"Confound it," he thought, "when I get into that shed I shall be
dripping water all over the floor."

But he remained at his post, and in due course he was rewarded by seeing
Benson appear at the door in the fence, and after locking it behind him,
start off down the railway towards Ferriby.

As before, Willis waited until the manager had got clear away, then
slipping across the line, he produced his bent wire, opened the door,
and five minutes later stood once more in the office.

From the nature of the case it seemed clear that the entrance to the
cellar, if one existed, would be hidden. It was therefore for secret
doors or moving panels that he must look.

He began by ascertaining the thickness of all the walls, noting the size
of the rooms so as to calculate those he could not measure directly. He
soon found that no wall was more than six inches thick, and none could
therefore contain a concealed opening.

This narrowed his search. The exit from the building could only be
through a trap-door in the floor.

Accordingly he set to work in the office, crawling torch in hand along
the boards, scrutinizing the joints between them for any that were not
closed with dust, feeling for any that might be loose. But all to
no purpose. The boards ran in one length across the floor and were
obviously firmly nailed down on fixed joists.

He went to the bedroom, rolling aside the m