ton always wore in the air, and drew
the hood over his face. Then, after a searching look at the lean form of
the unconscious man in the other seat, he was off, the plane climbing
swiftly under his expert hand. He took a wide circle to the west and
north.

Soon Shiro and the two guards, hearing the roar of an approaching
airplane, looked out and saw what they supposed to be Crane's biplane
coming down with terrific speed in an almost vertical nose-dive, as
though the driver were in an extremity of haste. Flattening out just in
time to avert destruction it taxied up the field almost to the house.
The watchers saw a man recognizable as Seaton by his suit and his
unmistakable physique stand up and wave both arms frantically, heard him
shout hoarsely "... all of you ... out here," saw him point to Crane's
apparently lifeless form and slump down in his seat. All three ran out
to help the unconscious aviators, but just as they reached the machine
there were three silenced reports and the three men fell to the ground.
DuQuesne leaped lightly out of the machine and looked narrowly at the
bodies at his feet. He saw that the two detectives were dead, but found
with some chagrin that the Japanese still showed faint signs of life. He
half drew his pistol to finish the job, but observing that the victim
was probably fatally wounded he thrust it back into its holster and
went on into the house. Drawing on rubber gloves he rapidly blew the
door off the safe with nitro-glycerin and took out everything it
contained. He set aside a roll of blueprints, numerous notebooks, some
money and other valuables, and a small vial of solution--but of the
larger bottle there was no trace. He then ransacked the entire house,
from cellar to attic, with no better success. So cleverly was the
entrance to the vault concealed in the basement wall that he failed to
discover it.

"I might have expected this of Crane," he thought, half aloud, "after
all the warning that fool Brookings persisted in giving him. This is the
natural result of his nonsense. The rest of the solution is probably in
the safest safe-deposit vault in the United States. But I've got their
plans and notes, and enough solution for the present. I'll get the rest
of it when I want it--there's more than one way to kill any cat that
ever lived!"

Returning to the machine, DuQuesne calmly stepped over the bodies of the
detectives and the unconscious form of the dying Japanese, who was
utte