The detective nodded. "It's one, all right," he said, holding it out with a steady hand. "Looks harmless, don't it? Two binding-posts on one end. A rubber cap on the other. Notice that diaphragm." Nichols took the receiver and squinted at the rubber cap. "By George!" he said. "This is odd. There's a tiny hole drilled or punched in the center. It's about the same size as the bore of a twenty-two caliber revolver." "Look at your hands!" said Drew. "What the devil," he added with dawning conviction. "Say, Delaney, do you remember that spot of black under my left ear. The one you noticed after we left yesterday morning? The----" "Sure, Chief. That's where you got the smut--from that receiver!" "I got it when I picked up the telephone in the library downstairs and tried to get Central. Do you remember how long she took? This is the same receiver in all probability. The trouble-hunter removed it from the library connections, loaded it, and brought it up here. It looks like any ordinary receiver. The telephone company have some with binding posts and some without. This is an earlier model." "The spot of black was from the first discharge when Stockbridge was killed!" exclaimed Delaney. Drew ran his fingers around the inner rim of the rubber cap. He held them up. "See!" he exclaimed. "No wonder my neck was marked. That settles that mystery, Delaney. If we had any brains at all we would have connected the soot and the telephone. If we had done that we'd have solved the case early this morning, or yesterday morning. It's after one, now!" "This hole," said Nichols, "was the only thing in the whole dastardly scheme that could have been seen. It's the size of the end of a lead pencil. Funny you didn't notice it?" "I looked everywhere but there," admitted Drew. "The receiver hangs with the diaphragm end down. That's the reason I didn't see it. Well--there's always a reason," he added. "Now, Delaney, fetch me that trouble-hunter's satchel. We'll see what this pistol is made of and how it is made. I venture to say that it is simple." Delaney awoke from his stupor and lifted a rug which he tossed over the body of Cuthbert Morphy. He wiped his hands with a finite motion. He wheeled and slouched lankily across the polished floor. He returned with the lineman's kit. "Pliers," said Drew, as the big operative removed the straps and reached his hand inside. "I saw a pair there when we had it open before," the detective added, unscrewing the rubber cap of the receiver and lifting the thin metal diaphragm from the face of two tiny magnets which were wound with fine silk wire. "Regulation magnets," whispered Nichols, leaning over the detective's shoulder. "They're regulation except there's a hole drilled down between them. There must be a barrel all the way through the receiver." "We'll see. Got those pliers, Delaney?"