Whoom!"_

The sound of the bursting bomb was nearer.

"'Tis safer in the air," said Tam as he swung into his fuselage.
"Contact!"

A few seconds later, with a roar, the machine disappeared into the black
wall of darkness.

It came back in less than a minute well overhead and Blackie, straining
his eyes upward, followed its progress against the stars until it melted
into the sky.

_"Whoom!"_

"He is looking for us," said Blackie; "stand by your hangars."

To the northwest two swift beams of light were sweeping the sky
urgently. From a point farther south sprang another beam.

"If Fritz doesn't locate us now he ought to be shot," growled Blackie.

But apparently Fritz had overshot the aerodrome, for the next explosion
came a mile to the west.

"Tam will see the burst," said young Austin and Blackie nodded.

There were no other explosions and they waited for ten minutes, then--

"_Ticka-ticka-ticka-ticka!_"

The sound came from right overhead.

"Tam's got him," whooped Blackie; "the devil must have been flying low."

"_Tocka-tocka-tocka-tocka!_"

"That's Fritz," said Blackie, "and that's Tam again."

Then one of the waving searchlights strayed in their direction, and down
its white beam for the space of a hundred yards slid a ghostly white
moth. It dipped suddenly and fell out of the light and in its wake, but
above, burst three little green balls of fire--Tam's totem and
sign-manual.

"Landing lights!" roared Blackie, and they had hardly been switched on
when Tam swooped to the ground.

In the meantime a motor-car had gone swiftly in the direction of the
fallen Hun machine.

"He crashed," said Tam breathlessly, as he jumped to the ground; "A'm
afeered the puir body is hurt."

But the poor body was neither hurt nor frightened, nor indeed had he
crashed.

In point of fact he had made a very good landing, considering the
disadvantages under which he labored. They brought him into the
mess-room, a tall stripling with shaven head and blue laughing eyes, and
he took the coffee they offered him with a courteous little bow and a
click of his heels.

"Baron von Treutzer," the prisoner introduced himself.

"I was afraid that a thousand meters was too low to fly, even at night,"
he said; "I suppose I didn't by any lucky chance get you. By the way,
who brought me down? Tam?"

"Tam it was," said Blackie cheerfully, "and you didn't get us."

"I am sorry," said the baron. "May I ask you whether it was