When his heavy burden pulled him out of sure-footedness, and he plunged into a choya, or when the strange, deceitful, uncanny, almost invisible frosty thorns caught and pierced him, then there was call for all of fortitude and endurance. For this cactus had a malignant power of torture. Its pain was a stinging, blinding, burning, sickening poison in the blood. If thorns pierced his legs he felt the pain all over his body; if his hands rose from a fall full of the barbed joints, he was helpless and quivering till Yaqui tore them out. But this one peril, dreaded more than dizzy height of precipice or sunblindness on the glistening peak, did not daunt Gale. His teacher was the Yaqui, and always before him was an example that made him despair of a white man's equality. Color, race, blood, breeding--what were these in the wilderness? Verily, Dick Gale had come to learn the use of his hands. So in a descent of hours he toiled down the lava slope, to stalk into the arroyo like a burdened giant, wringing wet, panting, clear-eyed and dark-faced, his ragged clothes and boots white with choya thorns. The gaunt Ladd rose from his shaded seat, and removed his pipe from smiling lips, and turned to nod at Jim, and then looked back again. The torrid summer heat came imperceptibly, or it could never have been borne by white men. It changed the lives of the fugitives, making them partly nocturnal in habit. The nights had the balmy coolness of spring, and would have been delightful for sleep, but that would have made the blazing days unendurable. The sun rose in a vast white flame. With it came the blasting, withering wind from the gulf. A red haze, like that of earlier sunsets, seemed to come sweeping on the wind, and it roared up the arroyo, and went bellowing into the crater, and rushed on in fury to lash the peaks. During these hot, windy hours the desert-bound party slept in deep recesses in the lava; and if necessity brought them forth they could not remain out long. The sand burned through boots, and a touch of bare hand on lava raised a blister. A short while before sundown the Yaqui went forth to build a campfire, and soon the others came out, heat-dazed, half blinded, with parching throats to allay and hunger that was never satisfied. A little action and a cooling of the air revived them, and when night set in they were comfortable round the campfire. As Ladd had said, one of their greatest problems was the passing of time. The nights were interminably long, but they had to be passed in work or play or dream--anything except sleep. That was Ladd's most inflexible command. He gave no reason. But not improbably the ranger thought that the terrific heat of the day spend in slumber lessened a wear and strain, if not a real danger of madness.