Carefully marking the spot, he diligently searched for the letters mentioned in the communication. Not a trace of a letter was visible; the virgin rock lay bare, and undefiled by human hands. Above, below, and on either side, his search was equally unsuccessful, and as he communicated the result of his examination to Mollie and Marie, consternation seized upon them. Could it be that they had been deceived, and that the contents of the letter were false, and made for some purpose of alluring Junius Cobb to this spot? They looked at each other in bewilderment. Suddenly the doctor exclaimed: "Ah! It may be that!" "What, doctor?" they both cried, excitedly. But the doctor made no reply; he was climbing up the cliff, straight up from the knife-mark in the rock. With the celerity of a man intensely excited, he cut and slashed away the ivy, and threw it into the ravine; then, looking at his watch, he noted that twenty-five minutes had passed since the shadow of the rock had reached the point which he had marked. Noting the variation of the shadow from the vertical for these twenty-five minutes, he drew his knife slowly and carefully up the face of the cliff, from the mark which he had made to where the shadow of the "Finger of God" then rested, the knife describing the path of the shadow. Turning to Mollie, who had been watching his movements in wonder, he said: "If the instructions are correct, then will the characters 'J. C.' be found near the line which my knife has described; for the letter, if true, as I have remarked, was written a long time ago, and the 'Finger of God' was taller then than it is to-day, as the elements must have worn many inches from its top in the course of a great number of years; its shadow was higher up the cliff, at any particular hour of the day, at a remote period, than it is to-day. Now come and examine closely along the line I have described." With diligence and care, all three scanned the face of the rock, scraped away the mold, and sought to find the key to the mysterious cavern. Suddenly Mollie gave a scream--an exultant scream--and cried: "Here it is! Here it is! I have found them!" Crowding about her, the other two saw before them the letters in the rock. Small, discolored, and covered with a green moss, it was a wonder they had been discovered at all. Yes, there they were, "J. C." Leaning over, Dr. Town took his penknife and carefully dug the moss away from the point of the J, and exposed the hole mentioned in the letter. There was no farce, no falsehood in the communication, after all; at least, not as regards the letters "J. C." and the hole in the J. The decisive moment had arrived.