The sun was just going down, a hissing globe of fire and torment. Already the lower limb was in contact with the jagged backbone of the mountain chain that rimmed the desert with purple and gold. Out on the barren, hard-baked flat in front of the corral, just where it had been unhitched when the paymaster and his safe were dumped soon after dawn, a weather-beaten ambulance was throwing unbroken a mile-long shadow towards the distant Christobal. The gateway to the east through the Santa Maria, sharply notched in the gleaming range, stood a day's march away, -a day's march now only made by night, for this was Arizona, and from the rising of the sun to the going down of the same anywhere south of that curdling mud-bath, the Gila, the only human beings impervious to the fierceness of its rays were the Apaches. "And they," growled the paymaster, as he petulantly snapped the lock of his little safe, "they're no more human than so many hyenas."