He had expected to detect signs of life in this quarter, and this
additional proof of Wellgood's absence from home made it look as if they
had come out on a fool's errand and might much better have stuck to the
road.

"No promise there," came in a mutter from his lips. "Shall I row in,
sir, and try to make a landing?"

"You may row nearer. I should like a closer view. I don't think we shall
attract any attention. There are more boats than ours on the water."

Sweetwater was startled. Looking round, he saw a launch, or some such
small steamer, riding at anchor not far from the mouth of the bay. But
that was not all. Between it and them was a rowboat like their own,
resting quietly in the wake of the moon.

"I don't like so much company," he muttered. "Something's brewing;
something in which we may not want to take a part."

"Very likely," answered Mr. Grey grimly. "But we must not be
deterred--not till I have seen--" the rest Sweetwater did not hear. Mr.
Grey seemed to remember himself. "Row nearer," he now bade. "Get under
the shadow of the rocks if you can. If the boat is for him, he will show
himself. Yet I hardly see how he can board from that bank."

It did not look feasible. Nevertheless, they waited and watched with
much patience for several long minutes. The boat behind them did not
advance, nor was any movement discernible in the direction of the
manufactory. Another short period, then suddenly a light flashed from
a window high up in the central gable, sparkled for an instant and was
gone. Sweetwater took it for a signal and, with a slight motion of the
wrist, began to work his way in toward shore till they lay almost at the
edge of the piles.

"Hark!"

It was Sweetwater who spoke.

Both listened, Mr. Grey with his head turned toward the launch and
Sweetwater with his eye on the cavernous space, sharply outlined by
the piles, which the falling tide now disclosed under each contiguous
building. Goods had been directly shipped from these stores in the old
days. This he had learned in the village. How shipped he had not been
able to understand from his previous survey of the building. But he
thought he could see now. At low tide, or better, at half-tide, access
could be got to the floor of the extension and, if this floor held
a trap, the mystery would be explainable. So would be the hovering
boat--the signal-light and--yes! this sound overheard of steps on a
rattling planking.

"I hear nothing," whi