Bob critically examined the cartridges, making many unfavorable comparisons between them and the ones he had been in the habit of making, and then began the work of fastening the reel to the derrick, as well as setting the upright in position, which served as a guide to the rope that was to lower the cartridges in position. When that was done--and the moonlighters did not hurry in their work, anxious as they had been before, for they were determined that this last shot of theirs should be a perfect success--the more delicate task of filling the cartridges was begun. There were four of these, each capable of holding twenty quarts, and the spectators were not wholly at their ease, as can after can of the explosive fluid was poured into these frail-looking vessels, even though the moonlighters handled it much more carefully than Ralph had seen them handle that which had been used at the Hoxie well, on the famous night when Mr. Newcombe guarded their hut for them. As each tube was filled, the boys lowered it into position in the well, and the nervous anxiety which had assailed them the night before again took possession of Ralph and George. At last everything was ready for the launching of the iron bolt, which was to call into activity the explosive mass, that was to shatter the rock under which it was hoped the oil was concealed. The moment had come when the value or worthlessness of "The Harnett" was to be decided. CHAPTER XXXI. THE SHOT. It is barely possible that when Bob stood over the aperture with the iron poised in his hands which was to be the means of opening to them the mystery of the well, there was just a shade of fear at his heart that he had been mistaken in the signs, and that an upward rush of water, would be all that would follow the explosion. His partners noted a look of almost painful hesitation on his face for an instant, and, then, as it vanished, he dropped the go-devil, retreating to where the group of anxious watchers were gathered around George's chair. The seconds that followed the dropping of the iron were wonderfully long ones, and it seemed as if each one present ceased to breathe, as the time had come when the value or worthlessness of the well was to be decided. Then was heard three distinct reports, somewhat louder than had been heard at the Hoxie well, because of the charge being nearer the surface of the earth, and this was followed by the black, noisome vapor that wreathed slowly around the aperture as if sent by the demons of the earth to keep back those venturesome mortals who would seek to penetrate their secrets.