When these few things have been brought together, the prospector and the donkey set out. They wander over the hills and down into the canyons. If a rock is stained red, the prospector examines it to see whether it contains iron; if it is green, he looks for copper. In the canyons and along the creeks he often tests the gravel for traces of some valuable metal. If he finds any of these traces along the stream, he follows them on the bank until they stop; then he carefully examines the bank of the stream or the nearest hillside. If he continues to find bits of metal, they will lead him to a vein of ore, from which they have been broken by the wind, rain, and frost. Generally a prospector is looking for some one special metal, and in his search he often overlooks some other metal; for instance, thousands of the gold-seekers who rushed to California in 1849 hurried through Nevada on their way. If they had only known what was under their feet, they would have taken their picks and shovels and begun to dig, instead of trying to get out of the region as soon as might be. Ten years later, the California placers were becoming exhausted, and miners began to go elsewhere in their search for gold. Among those who were working in what is now the State of Nevada were two Irishmen who had been unlucky in California and had fared no better in Nevada. They wanted to go somewhere else, but they had not money enough for the journey; so they kept on with their work at the foot of Mount Davidson, washing the gravel and saving the little gold that they found. They were annoyed by some heavy black stuff that united with the quicksilver in their cradles, interfered with the saving of the gold, and put them in a very bad temper. At length a man named Henry Comstock came along, who told them that this black stuff was silver ore. They examined the mountain-side, and discovered the outcrop or edge of a great vein containing gold and also silver. It is no wonder that people rushed from the east and west to the wonderful new mines, for it was plain that these new "diggings" were not mere placers, but rich veins that many years of working might not exhaust. Every newcomer hoped to discover a vein; and within a year or two the district around the Comstock lode was full of deep shafts, many of them abandoned and half-hidden by low brush, but some of them yielding quantities of gold and silver. Before this, there had been only about a thousand people in what is now Nevada, but in two years after the discovery of silver, there were 16,000, and a new Territory was formed.