By dawn, he had landed gliders, with their small mataform transceivers, in isolated spots outside three moderate-sized cities within range of the boat. Dan then took another of the mataform units and buried it. Standing nearby, he mentally pronounced a key word. As he did this, the electro-chemical change in a nervous tract triggered a tiny implanted device that sent its imperceptible signal to the mataform transceiver. The transceiver interpreted the signal, and for an instant Dan sensed a shift in the pattern of things around him. Abruptly he was standing in the clearing where he had brought down the first glider. Around him were several tall wind-thrown trees. In the gray light of early dawn, he could barely make out the glider and little mataform unit clipped to it. A few minutes later, the unit was temporarily hidden, he had returned the glider to the boat, and he was picking up the second glider in a badly burned tract of forest near the second city. * * * * * When the three mataform units were all hidden, Dan paused for a moment to think through the next step. The three gliders, invisible to the naked eye as they passed high above the tree tops, might possibly have shown up on any of a number of detection devices, to give away both the starting point and the places where they had landed. It was now Dan's problem to outwit these detection devices. Dan clipped another mataform transceiver to a glider, put on the control helmet, and sent the glider dodging low and carefully through the trees. He found a spot about two miles away that suited him and landed the glider. He swiftly unloaded the boat and carried its contents to the buried mataform unit, where he mentally pronounced a new key word, which triggered the unit and took him to the glider and transceiver he had just landed. In a short time, he had the contents of the boat stacked beside the glider. Dan then disassembled the boat and engine, and stacked the parts beside the boat's piled-up contents. By now, the sun was well up, and Dan was becoming aware of a thrumming drone that grew steadily louder. He quickly dug up the buried mataform unit, clipped it to a glider, and hung the glider to an overhead limb by a green string, knotted so as to come undone at the first sharp pull.