Bird tore it open
and glanced sleepily at it.

"Get up, Carnes," he cried sharply. "Read this!"

The yawning detective glanced at the telegram. It contained only two
words and a signature. It was signed "Ivan," and read simply, "Watch
Wilmington."

"What the dickens?" he exclaimed as he studied the yellow slip. Dr.
Bird was hurriedly pulling on his clothes.

"Saranoff has slipped a cog this time," said the doctor. "He sent that
as a night message, but it was delivered as a straight message through
error. He has got further north than I expected. We will turn out our
pilot and take off. We should make Wilmington by daybreak. I'll
telephone Washington and have a couple of destroyers started up
Delaware Bay at once. We ought to give him a first class surprise
party. I suppose that Philadelphia was meant to be his next stop."

In an hour the army plane took off into the night. At seven o'clock
they were circling over Wilmington. The city had not been disturbed.
For an hour they flew back and forth before they landed. Startling
news awaited them. At six that morning an earthquake had struck
Wilmington, North Carolina. Half the town had sunk into the earth. Dr.
Bird struck his brow with his clenched fist.

"Score one for the enemy," he said grimly. "We were too sure of
ourselves, Carnes. We should have realized that he would hardly be so
far north yet. Well, I've got to use the telephone while we're
refueling."

* * * * *

Within an hour after landing they were again in the air One o'clock
found them over the stricken city. Dr. Bird wasted no time on
Wilmington but headed north along the coast. For a hundred miles he
skirted the shore, two miles out. With an exclamation of
disappointment he ordered the pilot to turn the plane and retrace his
route southward, keeping ten miles from the shore. Fifty miles south
he ordered the plane further out and again turned north. From time to
time they passed a ship of the air patrol which was steadily skirting
the coast, but none of them had seen a submarine. Off Cape Hatteras
the pilot asked for orders.

"The gas is running low. Doctor," he said. "I think we had better put
in somewhere and refuel. If we are going to keep the air much longer,
you had better get a relief pilot. I have been flying for thirty hours
out of the last thirty-six and I'm about done."

"Head back for Washington," said the doctor with a sigh. "I seem to
have gone off on a