On the second morning he was stiff and lame, and his hands were so sore that he could scarcely close his fingers on the pick handle, but he worked on, and at night had the tunnel completed under the track. At the close of the third day he went into the shed, dropped to the mouth of the tunnel, crawled through, and came out in the base of the water tank that was boarded up from the ground to the tank proper. Before retiring he carried a goodly supply of cartridges and stored them in the framework of the tank near the top, and then sat down to watch the sunset. The same glory flooded the west, and when the sun was down the same gaunt shadows came and stood in the gloaming, only more of them. They had begun to scent the food supply at the station and so grew less timid. The agent had by this time determined that it was only a waste of ammunition to shoot the hungry brutes, and when he showed no fight the wolves came so near that he could have reached them with a stone. Far away he thought he heard the roar of an approaching train. The muffled sound grew louder, but looking where the two shining threads of steel drew close together, and dipped down into the desert, he could see no break on the horizon. Sweeping the plain with his eager eyes he saw a black something coming out of the north-west. It looked like a low black cloud just rising from the earth. The strange sound grew louder, and the agent thought of the sudden storms of which he had read, but the quiet sky gave no sign of storm. Already he could see a big star burning in the west. The growling cloud came nearer with each passing moment, but still lay close to the sage-brush. It grew broader but no higher, and in its wake a gray fog arose, like the mist that hangs over a swamp on a summer’s morning. Higher and higher the gray cloud rose, trailing behind the black one, like the smoke from a locomotive. In a little while it covered the whole west and shut out the light from the far pink sky. The wolves, lifting their heads, listened to the roar of the advancing cloud. The darkness deepened as the roar of the cloud increased. The agent, with his rifle resting on his arm, stood and stared down the plain. A moment later the head of the cloud swept across the track just below the water tank. It looked like a regiment of cavalry riding the desert. It must be so, for he could hear hoofs rattling over the rails and cross-ties. Now the agent observed that they were riderless horses,--horses with horns,--and realized that this was no cloud, but a band of buffalo. He could see neither the beginning nor the end of the herd, and raising his rifle he began pumping lead into the flying band. With a great crash one of the animals drove its head against the base of the water tank and then lay still while the drove galloped past. The roar of ten thousand feet beating the desert, the wild snorts of the wounded brutes, and the mad rush of the flying mass, so excited the agent that he ran forward