officer turned from the window and looked straight at him.

"You can, and I'll tell you," he said. "Each envelope contained the
route the President's plane is to fly, the exact time schedule, and the
codes to be used in case the aircraft runs into trouble, or danger, and
all that sort of thing. In short, as I told you in Washington, the Nazis
would give almost anything to get hold of one of those sealed envelopes.
With that information in their possession, they could have delivered a
terrible blow to the United Nations. Think of it! The death of the
President and members of the American High Command! It would be like
setting our war effort back to the day of Pearl Harbor!"

The horrible thought made Dawson shiver in spite of himself, and he
thanked God that Freddy and he had destroyed their letters before von
Steuben had smashed them both to the ground. The President's death would
have been loss enough, but to have added the loss of the great leaders
of our military, naval, and air forces would have been world shaking
indeed.

"And now, sir?" Dawson asked after several moments of silence. "Now
another plan is to be carried out?"

Colonel Welsh didn't answer for a moment. He stared down at his two
hands folded on the edge of the little table, and the expression on his
thin face seemed to show a reluctance to answer that question.
Presently, though, he lifted his head and looked straight at the two
youthful air aces.

"We are now headed for Casablanca," he began quietly. "With the extra
tanks of fuel we have aboard, we can make it easily. If we reach
Casablanca without any trouble, I will be as sure as a man can be that
the enemy has not learned anything of the President's plan to fly there
himself. If we don't--"

The Chief of all U. S. Intelligence let the rest trail off into thin air
and made a little gesture with one hand. Dawson frowned and looked at
him earnestly.

"I don't think I get what you mean, sir," he said slowly.

"And neither do I, sir," Freddy Farmer spoke up.

For a moment the colonel held his lips pressed together in a thin, grim
line, and a hard light glittered in his eyes.

"In a thing like this," he said presently, "you can't afford to take
_any_ chances. You've got to be dead sure; as dead sure of everything as
it is humanly possible to be, from start to finish. I had utmost
confidence in your making the complete flight to Natal. And the way you
two did handle yourselves, when the odds w