ent to explain how they managed to build
the place without exciting suspicion. They probably had all the material
landed there labeled as preserved ginger, and they would take it down
below at night, long after the office and warehouse staff of Concessions
had gone home. The workmen probably came and went by way of the river,
also, commencing work after nightfall and going away before business
commenced in the morning."

"It beats me," said Dunbar, reflectively, "how masons, plumbers,
decorators, and all the other artisans necessary for a job of that
description, could have been kept quiet."

"Foreigners!" said Sowerby triumphantly. "I'll undertake to say there
wasn't an Englishman on the job. The whole of the gang was probably
imported from abroad somewhere, boarded and lodged during the day-time
in the neighborhood of Limehouse, and watched by Mr. Ho-Pin or somebody
else until the job was finished; then shipped back home again. It's
easily done if money is no object."

"That's right enough," agreed Dunbar; "I have no doubt you've hit upon
the truth. But now that the place has been dismantled, what does it
look like? I haven't had time to come down myself, but I intend to do so
before it's closed up."

"Well," said Sowerby, turning over a page of his notebook, "it looks
like a series of vaults, and the Rev. Mr. Firmingham, a local vicar whom
I got to inspect it this morning, assures me, positively, that it's a
crypt."

"A crypt!" exclaimed Dunbar, fixing his eyes upon his subordinate.

"A crypt--exactly. A firm dealing in grease occupied the warehouse
before Kan-Suh Concessions rented it, and they never seem to have
suspected that the place possessed any cellars. The actual owner of
the property, Sir James Crozel, an ex-Lord Mayor, who is also ground
landlord of the big works on the other side of the lane, had no more
idea than the man in the moon that there were any cellars beneath the
place. You see the vaults are below the present level of the Thames at
high tide; that's why nobody ever suspected their existence. Also, an
examination of the bare walls--now stripped--shows that they were pretty
well filled up to the top with ancient debris, to within a few years
ago, at any rate."

"You mean that our Chinese friends excavated them?"

"No doubt about it. They were every bit of twenty feet below the present
street level, and, being right on the bank of the Thames, nobody would
have thought of looking for them