"We found it, sir, in about two feet of water, partly covered with sand. Its weight was gradually sinking it into the bottom." Joe laughed hysterically and lapsed into negro dialect: "See, Mars Oakes! see, boss! I dun tole you the truth." Oakes seized the handkerchief, and we all looked inside. It contained a few large cartridges. "They match the one I found in the cellar, and those of the old revolver," said Oakes. "The man of the Mansion mysteries and assaults _is_ the murderer of Mr. Mark." We were intensely excited as we stood there viewing the evidence that was so conclusive. Not one of us made a remark, but the deep breathing of some and the pale faces of others showed the interest that was felt by one and all. Oakes discovered on one end of the handkerchief the initial "S," and we all studied its appearance closely. Then Oakes asked Hallen if such handkerchiefs were unusual in Mona. "No, not at all; there are hundreds of them sold here, especially to the laborers on the water-works--the Italians and Poles," answered the Chief. "It is a very peculiar 'S,'" said Oakes, as he folded the handkerchief and put it in his pocket, giving the cartridges to Martin. He said nothing more, but seemed serious and thoughtful, as usual. And then we set out all together on a wild drive to police headquarters. Despite the lateness of the hour, the crowds were increasing. The square, with the hotel on one side and headquarters on the other, was the centre of a vicious body of men, pushing, struggling and forcing its way along, and pausing now and again to surge around headquarters. We could all see that Hallen was to have his hands full. "I should like to see Skinner very much," remarked Oakes in a sarcastic vein. "I should like to see his arms," said Moore; "they might be interesting." Oakes looked at the speaker with one of his undefinable expressions. We could not tell whether the shot had been a true one or not. _CHAPTER XVIII_ _Misadventures_ Toward morning the crowd thinned. The street grew more quiet, although the very air still throbbed with action, even as the heart-strokes within us. Quickly as events had come, we were yet only in the midst of our experiences. The clock in the Chief's room was striking three, and drowsiness was stealing over me, as over the outside world, when a knock came at the front door and Hallen admitted a man, weary-eyed and panting. I recognized him as one of the men who had been masquerading about the Mansion as a carpenter. He was dressed in a heavy jersey without a coat, and was evidently suffering from fatigue. He walked over to Oakes and spoke to him in a low voice. The detective asked a question or two, and turning looked at Dr. Moore, asleep in a chair, fagged out, then at me. I was wide awake, anticipating more trouble. "Stone," said he, "are you good for a ride with me on horseback? We have found something important." "Yes," I answered, "I am ready."