"Gold does not come in quarries like building stone," he said with a laugh. "Did you think it came in great masses of rock?" "No," answered Roger, "but I thought it came in veins through the rocks." "So it does, but you can find it in sand. What is sand?" The boy thought a moment. "Why," he said, at length, "sand is rocks ground small by the action of wind and water." "Very well," said his chief. "Now if some of the rocks ground small contained a vein of gold, what would happen to it?" "The gold would be turned into sand, too," answered the boy. "Only in part," said the older man. "The gold is hard and heavy, and when it is eroded from the rocks it comes in flakes rather than small particles. Then, you see, when sand is washed this way," illustrating by a cradling motion, "the gold sinks to the bottom as the sand is washed away from it, and you can take out the pieces of gold with comparative ease." "Then it ought to be very easy to get gold!" exclaimed the boy with visions of Arabian Nights wealth floating before his eyes. "Don't you believe it. There is gold on this river bar, as I have shown you, and, indeed, gold has been reported by the Survey on nearly all the bars of the Tanana River and its tributaries; but the geological history of the region is far from perfectly known yet, and the tracing to their original sources the débris of the Cantwell and Tanana Rivers is an excessively complicated subject. Of course, if you found the original vein of gold from which these flakes came, it would pay big, but near its source it may be in sufficient quantity to pay well, even in placer form." "But if you can wash it right out of the sand," objected Roger, his imagination fired by the sight of the particles of metal, "why not get it that way?" "Nothing easier," replied the geologist. "Thousands of people might come up here and wash the sands of this and other rivers, the White River in particular, but it doesn't follow that they would get enough to pay them for their trouble. Just think what it would cost to get up here! I suppose from the 'colors' in this sand, each one of us could wash from six to ten dollars' worth of gold a day through the summer, but what use would that be? It wouldn't pay the expenses of the trip; still hundreds have made small fortunes by such methods." "Then prospecting for gold's not so easy after all?" "It's one of the hardest lives I know," was the reply, "and the most dissatisfying. If you happen to strike a 'pay-streak,' as it is called, it may be very profitable." "But if you strike the original vein?" asked Roger. "Isn't it pretty good then?"