They turned north in order to get in line with the sun; and out of the tail of their eyes they saw the lake march with them. When they finally turned to the west again it faced them once more. They linked arms suddenly and trudged on, hungry, parched, beset by superstitious fears, but not forgetting to turn every half hour and glance at the sun until he passed the meridian and pointed for the west. And suddenly the lake seemed to slip behind a wall. "There is really something there this time," said Roldan, closing one eye and curving his hand about the other. "It is ugly enough to be real. It is no use to say how far anything is in this place, but I should think we would reach it before long." And long before they did reach it they knew what it was--a thicket of cacti some two miles long and of unknown depth. The plants were eight or ten feet high, and the broad thick leaves, spiked, as only the leaves of the cactus are, looked to be welded together. But that was from a distance. When the boys reached the thicket they saw that the plants in reality were some feet apart, although there appeared to be no end to them. The boys sat down suddenly, their strength deserting them. They threw their arms forward on their knees and dropped their heads. For a half hour or more they sat motionless, then Roldan looked up and fixed his glassy eyes on the forbidding wall, which at close proximity seemed to girt the horizon. "If we tried to go round it," he said, "there is no knowing where we should find ourselves. We had better go straight ahead, if possible. If it is too thick we can turn back." "At least we could not see this horrible desert for a while," said Adan. "I am willing." "And, who knows? Los Angeles may be just on the other side." Their utterance was thick. Their veins felt as if packed with lead, not so much from need of food as need of drink. But they stumbled to their feet and entered the cactus forest. They were obliged to pursue their way in single file; the spikes were long, and many of the larger leaves abutted so obstructively that they were obliged to go down on their hands and knees and crawl. Nor could they maintain a straight course, but zig-zagged among the great plants as nature permitted. More than once they heard the rip of silk, more than once blood sprang through their skin. Their progress was slow and fraught with peril, their only consolation that the end must come sooner or later. Night came suddenly. They were near an open a few feet in circumference. They lay down side by side, knowing that a step at night might mean instant blindness. The cactus never moves, not even in a storm. There was not a breath of wind to-night. The thick dull green plant-trees looked as solid as stone, a petrified forest. The sky had never seemed so high above, the stars so hard and bright. Adan moistened his lips with his tongue. "Do you feel that you can last another day?" he asked. "I expect to die of old age."