They had expected the capture and hobbling of the unicorns to be a difficult and dangerous job and it was. But when they were finished the unicorns were helpless. They could move awkwardly about to graze but they could not charge. They could only stand with lowered heads and fume and rumble. The ore sacks were tied on one frosty morning and the men mounted. The horn-leg ropes were loosened so the unicorns could travel, and the unicorns went into a frenzy of bucking and rearing, squealing with rage as they tried to impale their riders. The short spears, stabbing at the sensitive spot behind the jawbones of the unicorns, thwarted the backward flung heads and the unicorns were slowly forced into submission. The last one conceded temporary defeat and the long journey to the south started, the unicorns going in the run that they could maintain hour after hour. Each day they pushed the unicorns until they were too weary to fight at night. Each morning, rested, the unicorns resumed the battle. It became an expected routine for both unicorns and men. The unicorns were released when the ore was unloaded at the foot of the hill before the caves and Schroeder went to the new waterwheel, where the new generator was already in place. There George Craig told him of the unexpected obstacle that had appeared. "We're stuck," George said. "The aluminum ore isn't what we thought it would be. It's scarce and very low grade, of such a complex nature that we can't refine it to the oxide with what we have to work with on Ragnarok." "Have you produced any aluminum oxide at all?" Schroeder asked. "A little. We might have enough for the wire in a hundred years if we kept at it hard enough." "What else do you need--was there enough cryolite?" he asked. "Not much of it, but enough. We have the generator set up, the smelting box built and the carbon lining and rods ready. We have everything we need to smelt aluminum ore--except the aluminum ore." "Go ahead and finish up the details, such as installing the lining," he said. "We didn't get this far to be stopped now." But the prospecting parties, making full use of the time left them before winter closed down, returned late that fall to report no sign of the ore they needed. Spring came and he was determined they would be smelting aluminum before the summer was over even though he had no idea where the ore would be found. They needed aluminum ore of a grade high enough that they could extract the pure aluminum oxide. Specifically, they needed aluminum oxide.... Then he saw the answer to their problem, so obvious that all of them had overlooked it.