Captain Carter's huge bulk--he was about as tall as I am--towered over us as we sat before Halsey's desk. "If you lads have told anyone--said anything--let _slip_ the slightest hint about it...." Snap smiled with relief; but he turned solemn at once. "I haven't. Not a word!" "Nor have I!" I declared. The Grantline Moon Expedition! We had not thought of that as a reason for this summons. Johnny Grantline was a close friend of ours. He had organized an exploring expedition to the Moon. Uninhabited, with its bleak, forbidding, airless, waterless surface, the Moon--even though so close to the Earth--was seldom visited. No regular ship ever stopped there. A few exploring parties of recent years had come to grief. But there was a persistent rumor that upon the Moon, mineral riches of fabulous wealth were awaiting discovery. The thing had already caused some interplanetary complications. The aggressive Martians would be only too glad to explore the Moon. But the United States of the World, which came into being in 2067, definitely warned them away. The Moon was Earth territory, we announced, and we would protect it as such. There was, nevertheless, a realization by our government, that whatever riches might be upon the Moon should be seized at once and held by some reputable Earth Company. And when John Grantline applied, with his father's wealth and his own scientific record of attainment, the government was glad to grant him its writ. The Grantline Expedition had started six months ago. The Martian government had acquiesced to our ultimatum, yet brigands have been known to be financed under cover of a government disavowal. And so our expedition was kept secret. My words need give no offence to any Martian who comes upon them. I refer to the history of our Earth only. The Grantline Expedition was on the Moon now. No word had come from it. One could not flash helios even in code without letting all the universe know that explorers were on the Moon. And why they were there, anyone could easily guess. And now Colonel Halsey was telling us that the news was abroad! Captain Carter eyed us closely; his flashing eyes under the white bushy brows would pry a secret from anyone. "You're sure? A girl of Venus, perhaps, with her cursed, seductive lure! A chance word, with you lads befuddled by alcolite?" We assured him that we had been careful. By the heavens, I know that I had been. Not a whisper, even to Snap, of the name Grantline in six months or more. Captain Carter added abruptly, "We're insulated here, Halsey?" "Yes. Talk as freely as you like. An eavesdropping ray will never get through to us."