He passed by four children playing a game in front of the caves that day; some kind of a checker-like game in which differently colored rocks represented the different children. One boy was using red stones; some of the rubies that had been brought back as curios from the chasm. Rubies were of no use or value on Ragnarok; only pretty rocks for children to play with.... Only pretty rocks?--_rubies and sapphires were corundum, were pure aluminum oxide!_ He went to tell George and to arrange for a party of men to go into the chasm after all the rubies and sapphires they could find. The last obstacle had been surmounted. The summer sun was hot the day the generator hummed into life. The carbon-lined smelting box was ready and the current flowed between the heavy carbon rods suspended in the cryolite and the lining, transforming the cryolite into a liquid. The crushed rubies and sapphires were fed into the box, glowing and glittering in blood-red and sky-blue scintillations of light, to be deprived by the current of their life and fire and be changed into something entirely different. When the time came to draw off some of the metal they opened the orifice in the lower corner of the box. Molten aluminum flowed out into the ingot mold in a little stream; more beautiful to them than any gems could ever be, bright and gleaming in its promise that more than six generations of imprisonment would soon be ended. * * * * * The aluminum smelting continued until the supply of rubies and sapphires in the chasm had been exhausted but for small and scattered fragments. It was enough, with some aluminum above the amount needed for the wire. It was the year one hundred and fifty-two when they smelted the aluminum. In eight more years they would reach the middle of Big Summer; the suns would start their long drift southward, not to return for one hundred and fifty years. Time was passing swiftly by for them and there was none of it to waste.... The making of ceramics was developed to an art, as was the making of different types of glass. Looms were built to spin thread and cloth from woods goat wool, and vegetable dyes were discovered. Exploration parties crossed the continent to the eastern and western seas: salty and lifeless seas that were bordered by immense deserts. No trees of any kind grew along their shores and ships could not be built to cross them. Efforts were continued to develop an inorganic field of chemistry, with discouraging results, but in one hundred and fifty-nine the orange corn was successfully adapted to the elevation and climate of the caves. There was enough that year to feed the mockers all winter, supply next year's seeds, and leave enough that it could be ground and baked into bread for all to taste.