Sorenson's horse suddenly went to its knees. But the man leaping clear took the ground on his feet and instantly set off at a run for the line of brush in the draw some seventy or eighty paces away. A last spurt Weir's pony made, bringing his rider to within thirty yards of the cattleman, who glancing over his shoulder halted, swung about, fired a shot and again started to run. The pony under Weir came to an abrupt stop, shaking. He was done, whether from exhaustion or the bullet the engineer did not wait to see. Flinging himself out the saddle he raced after his man, taking the rough trail leading up the slope in swift strides. On foot Sorenson was no match for him. But the latter had the start; he was now almost within reach of the thick screen of bushes; and he bent every energy to make the ambuscade. Still running, Weir flung up his gun and fired. Close the shot must have gone to Sorenson, so close as to inject into the man's mind recollection of his pursuer's accuracy and a fear of a bullet in his back, for when within twenty feet of the bushes he dropped behind a small bowlder, whence he fired twice at Weir but without striking his mark. Neither man after the furious ride and the concluding run on foot was fit for sure marksmanship. This Weir realized, so stopped where he was some forty feet off from Sorenson's stone in order to regain his breath and calm his nerves. Of the cattleman he could see nothing; the man crouched low out of sight, perhaps reloading his weapon, perhaps steeling himself for a dash across that small moonlit space that separated him from safety, or perhaps preparing for a quick upward spring and a fresh volley directed at his foe. It may be questioned if in his heart Sorenson was not almost disposed to fight the matter out. He was no coward; his original hatred for the engineer had by recent events been swelled to a diabolical desire to kill; and now even if he, Sorenson, succeeded in slipping away, his whereabouts would be known unless he destroyed the man. Safety demanded that he not only escape but escape without this witness. Weir had not sought cover. He stood upright, his revolver ready, trusting to have an advantage in his speed when it came to an exchange of shots. Then he began an advance, a slow noiseless circling advance that at the same time of taking him closer to his enemy brought him round on his flank. Sorenson's hand and pistol appeared and half his face while three shots rattled from his gun, two at the spot where Weir had been and one at him in his new position, which the hiding man had immediately located. The last shot ticked the engineer's sleeve. In return Weir fired twice, the first bullet striking the rock and ricocheting off with a loud whine, while the second struck the pistol from Sorenson's hand. Instantly Weir sprang forward.