tion. Only one hundred dollars! A low price for cancer cure!

"Another thing: Dad asked me to tell you that he'd appreciate your help
in stopping this ultra-modern pirate. If you go down to see him in the
morning, you'll doubtless be able to make the necessary arrangements."

"I'll do so gladly. I wonder, though, if you know more about this than I
do. Did they try that C-32L mask on an animal?"

"The Pirate was telling the truth. They tried it on a dog and he went to
sleep forever. But do you have any idea how that gas does all it does?"

Now Arcot shook his head. "I don't know what the gas is, but have a lead
on how it works. You may know that carbon monoxide will seep through a
solid plate of red-hot steel. That has been known for some three hundred
years now, and I have to hand it to this Pirate for making use of it.
Even in the war of 2075 they didn't find any practical application for
the principle. He has just found some gas that induces sleep in very low
concentrations, and at the same time is able to penetrate to an even
greater extent than carbon monoxide."

"I was wondering how he stores that stuff," Morey commented. "But I
suppose he makes it as fast as he uses it, by allowing two or more
constituents to react. It might well be simple enough to store them
separately, and the air-stream blowing past him would carry the gas
behind him, permitting him to lay a stream of it in front of the big
plane. Is that about it?"

"That was about what I had figured. One of the things I want to do when
I go with that Invalid Special tomorrow is to get some samples for
analysis."

"That's a pretty big order, isn't it, Dick? How are you going to handle
it, or even get it into your apparatus?"

"Easily enough as far as getting the sample goes. I have already had
some sample bottles made. I have one of them in the lab--excuse me a
moment." Arcot left the room, to return a few minutes later with a large
aluminum bottle, tightly closed. "This bottle has been pumped out to a
very good vacuum. I then swept it out with helium gas. Then it was
pumped out again. I hope to take this into some gas-filled region, where
the gas will be able to leak in, but the air won't. When it comes to
going out again, the gas will have to fight air pressure, and will
probably stay in."

"Hope it works. It would help if we knew what we were bucking."

* * * * *

The next morning Arcot had a long conference with