"I assume you will go by air. That means very little baggage. One tropical suit and the rest rough clothing would be my suggestion." Scotty changed the subject. "Sir, have you any idea what might have happened to our friends?" The officer shrugged. "No more than you have. Scientists generally are not rich enough to rob, but they are not so poor that they can be harmed with impunity. Robbery is always possible, although unlikely, with one exception. Did they have any weapons with them?" "Shannon had a hunting bow and arrows," Mr. Brant replied. "He planned to collect some specimens. Briotti had no weapon at all." "Then that eliminates the only robbery possibility I can think of. Had they been well armed, Moros might have attacked to get their weapons. The Moro loves weapons of all kinds, and may even kill to get them--a point you might remember." Rick shook his head. "It's hard to imagine why anyone would want to harm them--if anyone did. I think we'd better get to Mindanao as soon as possible. When do we leave, Dad?" "Tomorrow night, son. I made reservations for you while I was in New York this morning." "Are we going to take special equipment?" Scotty asked. Rick had been thinking about that very point. "I'm planning to take the Megabuck network. It will be useful if we have to separate." The little network of three miniature radio units, transmitters, and receivers combined, had been of invaluable help in rounding up a group of foreign agents bent on stealing the plans for a United States intercontinental ballistic missile. The unusual name, Megabuck, had grown out of a joke Rick had conceived about a "million bucks" television quiz program. Two of the sets were pocket size, and used hearing-aid-type earphones. The third had been made in the form of an ornamental hair band for Rick's sister Barby to wear. The tiny microphone worked by sound induction through the bones of the head. The earphone was incorporated into one end of the band. Zircon and Scotty agreed that the radio units might come in handy, and the physicist added, "I have a pocket-size, battery-operated wire recorder I use for making notes. I think I'll take that. It may be helpful for recording conversations for later translation." "A good idea," the colonel approved. "The local dialect is called Chebucano. Of course many people speak some English. Have you an atlas? I think it might be useful if we went over a map of Mindanao and the Sulu Sea area." The map study was very helpful. The three absorbed Colonel Rojas' fund of information about the area. It was a part of the world none of them had ever seen, located only a few degrees above the Equator in the deep tropics. To the west of Mindanao was the Sulu Sea, with the Celebes Sea to the south. The widely scattered centers of civilization had famous, imagination-stirring names, like Jolo, Tawi Tawi, Cotabato, and Zamboanga.