SILVER KINGS (286 pp.)Oscar Lewis Knopf ($4).
Panning out the thin gold in Nevada's Carson Valley in the 1850s, miners cursed a heavy blue sand that clogged their rockers. In 1859, "Old Pancake" Comstock and three others, playing a hunch, staked out a 1,500-ft. claim around the mouth of a small spring where the blue sand was thick. They sent a sample of crumbly stuff across the mountains to an assayer in Grass Valley, Calif. He tested it twice, to be sure. There was no doubt: the stuff that gold miners had cursed and kicked aside was rich in silver.
That was the...