One of the bulletins explained in somewhat guarded language, that new A-bomb experiments were being made--not in mid-Pacific, in Bikini, but in the heart of the Kalahari Desert! So careful were the brass hats in this important series of tests, that no words in any civilized tongue were allowed to be spoken even on intercom sets! The report didn't mention Mangbetu, but it did say "little known African dialects." This wasn't an unusual procedure, by the way--Comanche Indians had been so employed in World War II. And what were those people testing, besides the newest thing in A-bombs? "Part of the test," said the voice of the announcer, "involves an amazing above-ground bomb-shelter! This shelter, of secret manufacture, is believed to be proof against anything except the explosion of the planet itself. Not only is each such shelter capable of great extension, thus to handle large groups of people, but built into it is something new in provisioning. People who are forced into these shelters by sudden attack, are automatically provided with food, water and equable temperature, by a process which provides these necessities as separate exudations from the inner walls of the bombproofs! "Some fear was expressed, in the midst of the tests," said the announcer, "that there were traitors even among the carefully screened technicians--for despite orders, for a period of three days not only English but many other languages, including the secret dialect used by the technicians, were heard in their intercoms!" I shivered at that, remembering how, for three days, we had tried every tongue of which we could think. Gradually a picture was beginning to emerge. "It was feared for some time that some potential aggressor nation had managed somehow to get past the Kalahari guards and ferret out secret information--or else that there was already a fifth column among the technicians!" No mention anywhere, of the Shadow Men! I was scared stiff when I realized this. For those Shadow Men, it now seemed, had accomplished something the A-bomb had not been able to do; they had got inside the bombproof, killed Yount--and could easily have killed us all--and got out again. "The experiments," said the announcer, "were of course carried out by the United Nations Security Council. The results have not been announced in every detail, but the world _has_ been informed that complete security against the A-Bomb has been produced and will be available if ever there is another world war!" _But what about the Shadow Men?_ What good was the best bombproof if it could be entered so easily, and everybody inside it destroyed? On the next day after our return I picked up a brief broadcast which I could easily have missed.