tor pumps. It had been washed out by the incoming good air later,
for the emergency pilot had not been affected.

Now the investigation led them to the mail-room. Despite the refractory
nature of the metal, the door had been opened by melting or burning out
the lock. And an opening had been burned into the safe itself! Opened by
melting it through!

A bond shipment was due the next day, and the airline officials planned
to be on the watch for it. It would get through safely, they were sure,
for men were put on board in steel chambers hermetically welded behind
them, with oxygen tanks and automatic apparatus sealed within to supply
them with clean air. The front of the tanks were equipped with
bullet-proof glass windows, and by means of electrically operated
controls the men inside could fire machine guns. Thus they were
protected from the Pirate's gas and able to use their weapons.

The ship was accompanied by a patrol of Air Guardsmen. Yet, despite,
this, cancer cases were aboard with the hope of being gassed.

When the plane reached the neighborhood of San Francisco, there had been
no sign of an attack. The Pirate might well retire permanently on a
million, if he were alone, as the singular signature indicated; but it
seemed much more probable that he would attempt another attack in any
case. Well, that just meant watching all the planes from now on, a
tremendous job for the Air Guard to handle.

The leader of the patrol turned in an easy bank to descend the ten miles
to Earth, and his planes followed him. Then suddenly through the
communicator came an unmistakable sound. _The plane automatically
signaling for an emergency pilot!_ That could only mean that the plane
had been gassed under the very eyes of his men!

The bonds were gone and the passengers gassed, and incredibly, the men
in the steel tanks were as thoroughly gassed as the rest.

The note was brief, and as much to the point as was the absence of the
bonds.

To the Officials of the Airport:

Restore as usual. The men in the tanks are asleep
also--I said the gas would penetrate _any_ material. It
does. A mask obviously won't do any good. Don't try that
C-32L mask. I warn you it will be fatal. My gas reacts
to produce a virulent poison when in contact with the
chemicals in the C-32L.

The Pirate

I.

On the thirty-ninth floor of a large New York apartment tw