"Search the tents," Zircon ordered. "Chahda, keep an eye on our two friends." The three Americans walked to the felt tents and began searching through them. Zircon used the infrared camera. Rick and Scotty took torches. Rick was feeling through a pile of furs when Zircon called, "Here are the flashlights!" Zircon's had run down, but Scotty's, and Chahda's big lights were still useful. They made the search much easier. Rick went back to the pile of skins and found that they were plastic-lined water bags, similar to the ones they had found on the way to Korse Lenken. Then, stacked in a corner of the tent, he found some Nansen bottles! At the same moment, Scotty called from the next tent. "Look what I found!" He had located the ammunition supply. There was powder and ball for the old muskets the Tibetans used, two boxes of machine pistol cartridges, and a small case of grenades! "Now we know where Ko got the one he tried to use on us," Rick said. "But where did they come from in the first place?" "The war," Scotty guessed. "There must be tons of ammo and ordnance of all kinds floating around China. What makes me wonder is why the Tibetans don't have modern rifles." "I suspect the answer is their natural conservatism," Zircon suggested. "They are slow to change. And such guns as they use are handed down from father to son. I don't doubt that modern rifles were offered them and that they refused." Rick knew something of the Oriental mind, although not much, and he realized that Zircon was probably right. In a land of ancestor worship, change was resisted. Scotty stuffed grenades in each pocket. "Just in case we get into a fight on the way out," he explained. Rick was glad to leave the deadly things to his friend. Scotty knew about grenades from his tour of duty in the Marines; he had thrown more than a few himself. "Nansen bottles in the next tent, professor," Rick said. "There must be something to this business of getting stuff out of the lake. But golly, you don't get heavy water out of natural water, do you?" "I don't know," Zircon said. "There is only one precedent I can think of. Have you ever heard of Lake Baikal?" Neither boy had. "It's a very large lake in Siberia, just above Mongolia," the scientist told them. "It is also very deep. A few years ago, before the Iron Curtain closed down, word came out of Russia that some scientists had succeeded in getting heavy water samples out of Baikal. That is the only precedent that I know. "It is true," he continued, "that heavy water has a tendency to sink. Naturally enough, since it is heavier. But for enough to form on the bottom of a body of water, there would have to be great depth and complete calm. Any current would stir the water up and the heavy water would merge with the normal once more." "In other words, you need a lake like this one," Rick concluded.