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 President Morey. At the end of it, he left the office, ascended to the roof, and climbed into his small helicopter. He rose to the local traffic level, and waiting his chance, broke into the stream of planes bound for the great airfields over in the Jersey district. A few minutes later he landed on the roof of the Transcontinental Airways shops, entered them, and went to the office of the Designing Engineer, John Fuller, an old schoolmate. They had been able to help each other before, for Fuller had not paid as much attention to theoretical physics as he might have, and though he was probably one of the outstanding aeronautical designers, he often consulted Arcot on the few theoretical details that he needed. Probably it was Arcot who derived the greatest benefit from this association, for the ability of the designer had many times brought his theoretical successes to practical commercial production. Now, however, he was consulting Fuller, because the plane he was to take that afternoon for San Francisco was to be slightly changed for him.