The two big boys grew daily in the science of gaining food and grew more and more of importance in their respective households. Sometimes either one of them might hunt alone, but this was not the rule. It was safer for two than one, when the forest was invaded deeply. But not all their time was spent in evading or seeking the life of such living things as they might discover. They had a home life sometimes as entertaining as the life found anywhere outside. CHAPTER XI. DOINGS AT HOME. Those were happy times in the cave, where Ab, developing now into an exceedingly stalwart youth, found the long evenings about the fire far from monotonous. There was Mok, the mentor, who had grown so fond of him, and there was most interesting work to do in making from the dark flint nodules or obsidian fragments--always eagerly seized upon when discovered by the cave people in their wanderings--the spearheads and rude knives and skin scrapers so essential to their needs. The flint nodule was but a small mass of the stone, often somewhat pear-shaped. Though apparently a solid mass, composed of the hardest substance then known, it lay in what might be called a series of flakes about a center, and, in wise hands, these flakes could be chipped or pried away unbroken. The flake, once won, was often slightly concave on the outside and convex on the other, but the core of the stone was something more equally balanced in formation and, when properly finished, made a mighty spearhead. For the heavy axes and mallets, other stones, such as we now call granite, redstone or quartose grit, were often used, but in the making of all the weapons was required the exercise of infinite skill and patience. To make the flakes symmetrical demanded the nicest perception and judgment of power of stroke, for, with each flake gained, there resulted a new form to the surface of the stone. The object was always to secure a flake with a point, a strong middle ridge and sides as nearly edged as possible. And in the striking off of these flakes and their finishing others of the cave men were to old Mok as the child is to the man. Ab hung about the old man at his work and was finally allowed to help him. If, at first, the boy could do nothing else, he could, with his flint scraper, work industriously at the smoothing of the long spear shafts, and when he had learned to do well at this he was at last allowed to venture upon the stone chipping, especially when into old Mok's possession had come a piece of flint the quality of which he did not quite approve and for the ruining of which in the splitting he cared but little.