When he looked he saw that the time for action had come. Standing fairly in the midst of the small clearing, the drill derrick was struck out boldly in the white moonlight, with every outline and detail sharply distinguishable. In the square of cleaned rock surface marked off by the four legs of the derrick frame Tregarvon saw a man crouching. The clinking noise was repeated and the watcher at the door faced about and felt his way in the inner darkness to the bed in the corner of the tool-room. “Wake up, Poictiers!” he called in low tones; “the play has begun!” Carfax sat up promptly and asked but a moment for the finding of himself. “I’m all here,” he said. “What’s doing?” For answer Tregarvon led him to the door and pointed to the square of bared bed-rock under the derrick frame. There was a man there, without doubt, but now he was standing up and was apparently examining something which lay in the palm of his hand. The sudden rush of the two from the tool shanty was quite evidently a surprise for the intruder, but he made no attempt to escape. So far from it, he lifted his soft hat politely and said: “Good evening again, gentlemen. You took me completely by surprise--as perhaps you meant to. I was quite sure that you were both safely in bed in Coalville by this time.” “No,” said Carfax very gently. “We have not been in Coalville at all: we have been here, waiting, quite patiently for--you, Mr. Hartridge.” “That was kind,” said Hartridge affably. “And, now that your patient waiting has been duly rewarded?----” “Now that we have caught you we shall ask you to solve that little problem in psychology for us,” put in Tregarvon. “We’d like to know what it is that you have just been dropping into that drill-hole.” “And if I assure you that I have been putting nothing into your drill-hole, what then, Mr. Tregarvon?” “In that case I shall ask Carfax to see that you don’t run away while I ascertain for myself,” was the firm rejoinder; and a careful dip of the long cleaning spoon into the test-hole brought up a half-dozen small metallic objects; cubes cut from a bar of tool-steel they appeared to be. Tregarvon handled the cubes and passed them on to Carfax. “We owe you something for a day lost and four drill points all but ruined, Mr. Hartridge,” he said rather grimly, adding: “But we’ll credit your account with this present failure to make us do it all over again to-morrow. Would you mind telling us in so many words what your object has been--or still is, perhaps?” The professor’s smile was imperturbably bland. “I am sure you wouldn’t be so harsh as to put me on the witness-stand in my own defense,” he said, still amiable. “Especially since you have no evidence of anything worse than a neighborly call at, perhaps, a somewhat unseasonable hour.” At this Carfax came quite close and he forgot to lisp when he said: “Mr. Hartridge, may I ask you to remove your overcoat for a moment? The night is a bit chilly, I know, but----”