"Placing tiltometers on the mountain," his father told him. "The instruments were ordered by phone from Caracas right after you left and got in on the first morning plane." Rick glanced at Scotty. He asked, "Exactly where are the others?" "Balgos and Connel are at the north end of the mountain, above Redondo. Williams and Zircon are up above us somewhere. They started the climb behind the hot springs." "I think we'll get a bite to eat," Rick said. "Unless you need us." "No. There's nothing for you to do right at the moment, but Balgos wants you to take some photos from the air later this afternoon." "Okay, Dad." Rick gestured, and Scotty followed him out. "All's quiet," Rick told his pal. "And a quiet time is a good time to do a little investigating. Let's go to the kitchen, get a couple of sandwiches, and eat them on the way." "To where?" Scotty asked. He grinned. "Don't tell me. To see what Connel is hiding over at his stations." "On the button. Let's get going." There was nothing whatever of interest at Connel's first two stations. The ground was torn up somewhat from the series of shots, but the boys could find no trace of anything unusual. They got back into the jeep, and Rick drove up the trail to the last station. He followed the path of broken vegetation Connel's jeep had made, noticing that the trail was dipping downward to a spot lower on the mountain than the other stations. They reached a patch of crushed and yellowed growth where Connel obviously had parked his jeep. There were oil stains on some of the broken leaves. Scotty pointed to a brown-paper cigarette stub. "Ever see Connel smoke one of those?" Rick hadn't. "He smokes cigars. Where do you suppose that came from?" Scotty got out of the jeep and bent over the butt. "The tip is still damp," he said. "Someone's been here very recently. We'd better keep an eye open." Trampled vegetation showed them the path to the firing place. Moving cautiously, the boys walked down the path, eyes constantly searching for signs of movement in the heavy growth. The clearing where Connel had placed his shots was only a short distance down the path. Rick examined it carefully, but it looked like all the others, except for one thing. The broken earth was yellow, and of a different texture than the deep jungle loam at the other stations. Rick walked into the shattered area and picked up a piece of the yellow ground. It broke in his hands. "Funny-looking stuff," he said. "Yes," Scotty agreed. "Take a look around while I keep a watch. I have a funny feeling we're not alone here." There was a fairly deep crater in the middle of the area. Rick stepped into it and kicked yellow earth out of his way. He was puzzled. There was nothing visible in the area except the yellow ground, and there was nothing about that to give him a clue to Connel's determination to keep them away.