the house, then
driven around, and out at the further gate of the drive. It returned by
the way it had come, racing down the hill at something considerably
exceeding the legal speed. The _thud-thud-thud_ of the motor died away,
and became inaudible.

"I'm glad the police aren't with us, and yet sorry," said Oppner. "This
is a whole-hog conspiracy properly. No wonder he was so hard to catch;
look at the class of people he's got in with him! Think of Elschild!
Gee! There's goin' to be a scene in a minute."

"For the present," said Alden, "we'll make no move; we'll just sit
tight. There's maybe a lot to arrive yet."

Just before the breeze came creeping up from the river again,
_thud-thud-thud_ was borne to their ears. Another car was approaching.

CHAPTER XVI

THE LAMP AND THE MASK

"10761," said Alden. "I wonder whose car that is."

None of the watchful trio had any idea. But whomever was within it, the
second car performed exactly the same man[oe]uvres as the first, and, a
few moments after its appearance, was lost to sight and hearing once
more.

But a matter of seconds later, came the familiar _thud-thud-thud_; and a
third car plunged up the hill and went swinging around the drive. Again,
no one of the three was able to recognise the number. Out by the further
gate of the drive it passed, turned, and flashed by them in the
darkness, to go leaping down the slope.

"Three," said Alden. "I wonder if there's any more."

His tone was thoughtful.

"Say," began Mr. Oppner, "we'd better get on with it now, because----"

"I know," Alden interrupted, "there may be only one more to come? You're
thinking that, after all those expected have arrived, there'll be
trouble in getting the door to open?"

"I was thinking that, too," said Martin. "Maybe they're all arrived as
it is; but we stand a still worse chance if we wait."

"Come on," said Mr. Oppner, with a rising excitement evident in his
voice. "We know there's one big fish in the net, anyway!"

_Thud-thud-thud!_

"There's another car coming," cried Alden. "Hurry up, Mr. Oppner! This
way. Mind your head through this broken part. We'll be on the steps as
the car comes around the drive!"

They crept through the gap below and ran across the road, Oppner as
actively as either of his companions. Already, the white beam of the
headlight was cutting-the gloom, below, where the road was heavily
bordered with trees.

"Just in time!"

Past the gate they