ne drove into the vapor--terrific
explosion--plane down in flames--others wrecked. The machine ascended
with meteor speed, trailing blue flame. Come on, boy, where's that old
bus? Thought I never wanted to fly a plane again. Now I don't want to do
anything but."

"Where to?" Slim inquired.

"Headquarters," Thurston told him. "Washington--let's go!"

* * * * *

From Los Angeles to Washington is not far, as the plane flies. There was
a stop or two for gasoline, but it was only a day later that they were
seated in the War Office. Thurston's card had gained immediate
admittance. "Got the low-down," he had written on the back of his card,
"on the mystery airship."

"What you have told me is incredible," the Secretary was saying,
"or would be if General Lozier here had not reported personally on
the occurrence at New York. But the monster, the thing you have
described.... Cy, if I didn't know you as I do I would have you locked
up."

"It's true," said Thurston, simply. "It's damnable, but it's true. Now
what does it mean?"

"Heaven knows," was the response. "That's where it came from--out of the
heavens."

"Not what we saw," Slim Riley broke in. "That thing came straight out of
Hell." And in his voice was no suggestion of levity.

"You left Los Angeles early yesterday; have you seen the papers?"

Thurston shook his head.

"They are back," said the Secretary. "Reported over London--Paris--the
West Coast. Even China has seen them. Shanghai cabled an hour ago."

"Them? How many are there?"

"Nobody knows. There were five seen at one time. There are more--unless
the same ones go around the world in a matter of minutes."

* * * * *

Thurston remembered that whirlwind of vapor and a vanishing speck in the
Arizona sky. "They could," he asserted. "They're faster than anything on
earth. Though what drives them ... that gas--steam--whatever it is...."

"Hydrogen," stated General Lozier. "I saw the New York show when poor
Davis got his. He flew into the exhaust; it went off like a million
bombs. Characteristic hydrogen flame trailed the damn thing up out of
sight--a tail of blue fire."

"And cold," stated Thurston.

"Hot as a Bunsen burner," the General contradicted. "Davis' plane almost
melted."

"Before it ignited," said the other. He told of the cold in their plane.

"Ha!" The General spoke explosively. "That's expansion. That's a tip on
their mo