thing you will ever do. You will
receive no other warning. Tomorrow night you will accompany us. Till
then, you remain my--guest."

The aviator nodded.

"Very well, sir," he accepted. "But, my machine?"

"I will attend to your machine."

"I should hate to leave it there on the roof."

"It will not be left on the roof."

"I don't understand, exactly--"

"There will be very many things you do not understand before this
expedition is over and done with. I need say no more."

Sharply he clapped his hands, thrice. In a moment, Rrisa appeared at
the door. The Master spoke a few guttural, aspirated words of Arabic.
Rrisa beckoned the stranger, who obeyed.

At the exit he faced about and sharply saluted. The Master returned
it. Then he vanished, and the door noiselessly closed behind them.

The Master turned to Bohannan.

"Now," said he, "these few last details. Time is growing very short.
Only a few hours remain. To work, Major--to work!"

At this same moment Auchincloss had already arrived at his rooms in
the McAlpine; and there, having carefully locked his door, had settled
himself at his desk with his sealed box before him.

For a moment he studied it under the electric light. Then, breaking
the wax with fingers tensed by eagerness, he tore it open. He spread
the contents on his blotting-pad. There was a small pocket-compass of
the best quality, a plain-cased watch wound up and going, a map and
a folded sheet of paper covered with typewriting. Auchincloss fell to
reading:

GENERAL ORDERS

You are to learn your specific orders by heart, and then destroy this
paper. You are to act on these orders, irrespective of every other
man. You are not to communicate the contents of this paper to any
other. This might upset the pre-arranged plan. You might try to join
forces, assist each other, or exercise some mistaken judgment that
might result in ruin. Each man is to keep his orders an absolute
secret. This is vital.

Each man, like yourself, is provided with a map, a watch, and a
compass. These watches are all self-luminous, all accurately adjusted
to synchronize to the second, and all will run forty-eight hours.

SPECIFIC ORDERS

Tomorrow, proceed inconspicuously to Tenafly, New Jersey, and hire a
room at the Cutter Inn. Carry your kit in a suit-case. At 7:30 p.m.,
go to Englewood. Go up Englewood Avenue toward the Palisades, turn
left (north) along the road near edge of cliff; proceed half a mile
and ente