g's more mysterious than ever, Mr. Elliott,' cried the
manager, 'Here's Inspector Bird of the police; he's been all over the
place, and he can't find any sign that a single fastening has been
tampered with; and a constable was on patrol all night.'

'Ah,' said the senior partner, 'have you looked at the trap which gives
on the old water-gate, White?'

'Old water-gate, sir!' cried White. 'What's that? I never heard of
such a thing.'

'No, possibly not; it's been out of service for so many years,' replied
Mr. Elliott; 'but it exists nevertheless, and we'll have a look at it.'

At this moment they were joined by Inspector Bird, and after a few
words between the police-officer and Mr. Elliott, the party of four men
and the scout went in search of the trap, the senior partner leading
the way with a lantern, for which he had asked, in his hand.

At the farther end of the great storeroom a flight of winding stone
steps led down into a huge cellar. Mr. Elliott went first, and threw
the light of his lantern back to guide the others; for there was no
hand-rail, and an ugly fall awaited anyone who might miss his footing.

'Why, sir,' said White, 'we never use this place; it's too damp. I've
only been down here once before in the five years I've been with you,
and there's neither door nor window to it.'

'Yes, White, there's a door,' replied Mr. Elliott; 'but it's in the
floor, and that's what we're going to look at.'

Guided by the shine of the lantern, the party marched across the floor
of the huge damp vault, and the senior partner paused beside a broad
trap-door, and threw the light upon it. He gave a long, low whistle,
and his brother said, 'Ah, first point to Slynn, Richard.'

'It is, it is,' said the latter, after a pause--'it certainly is.'

The trap-door was in two halves, meeting on a broad central bar slotted
into the stones at either end. Each half was secured by a couple of
big iron bolts running into sockets fixed on the bar. The right half
was firmly fastened; the left half was unfastened at this instant; the
great bolts were drawn back, and the sockets were empty.

The senior partner put his foot on the left flap. 'Here you are,
inspector,' he said. 'The thieves came in here.' And in a few words
he explained about the old water-gate.

'Then they had an accomplice inside, sir,' cried the inspector.

'Yes, that's very certain,' replied Mr. Elliott. 'He drew the bolts
before he left the warehou