Rucker watched the arm-waving for a full minute before it dawned upon him that the short man who seemed to be sighting something was making signals. The small square window of espial commanded nothing but the glade. The watcher crept cautiously to the end of the room facing toward the near-by brow of the mountain. The moonlight helped him to find the knot-hole he was looking for, but for a time the contracted field of vision revealed nothing but a forest tangle of moon-spattered shadows. Rucker had the patience of his craft, and the practical reasoning power that goes with it. The man under the oak was evidently signalling to some one to the eastward of his position at the edge of the glade: Rucker’s knot-hole in the planking at the end of the tool-house covered the same field: hence the eye at the knot-hole should be able to descry what was apparently visible to the eyes under the spreading oak. The mechanician stuck to his hypothesis until finally the fact proved it to be the true one. Far down among the trees, almost at the cliff’s edge, Rucker thought, a dancing light, such as might be made by a flaring pine torch, flashed up, flickered, and disappeared. The general aspect of the mystery remained as impenetrable as before, but one point became clear. The man under the tree was waving to the man with the torch, and some purpose, quite well understood by both, was getting itself forwarded. Rucker stayed at his peep-hole until the torch reappeared, flared steadily in one place for a few seconds, and then went out as suddenly as if a gust of wind had extinguished it. After which he tiptoed back to his window, and was there, looking on curiously, when the torch-bearer came tramping up from the eastward. There was a little delay when the upcomer joined the man under the oak. The watcher saw them taking the sighting mechanism, whatever it might be, apart and depositing some portion of it carefully in the square box; saw the two men resume their respective burdens and thread their way rapidly among the trees to the waiting vehicle. Then came the grinding protest of buggy wheels cramped short to turn in the narrow by-road, the _shough_ of a horse, minishing hoof-beats, and silence. By this time Rucker was beginning to stand somewhat less in awe of a forest wilderness which seemed, after all, to be anything but an uninhabited solitude. A fresh filling of the short black pipe was the preliminary to a careful scrutiny of the ground under the spreading oak-tree. There was but a thin layer of sandy top-soil overlying the rock through which the drill was to be churned on the morrow, but it sufficed to reveal what Rucker was looking for--three conical indentations made by the sharply pointed ends of a tripod, the stand of the sighting mechanism, level, transit, or telescope, used by the shorter of the two men.