Sutter's Mill.

On 24 January 1848 the American James Marshall discovered gold at John Sutter's mill in northern California. This strike set off one of the most dramatic economic events of the nineteenth century. When word got out concerning the gold's location, people soon began scurrying into the hills seeking even more of the precious yellow metal—and many found it, at least at first. Word of the placer (or surface) gold spread throughout the world. In 1849 alone, about eighty thousand people came to California; by 1854 three hundred thousand had arrived. Vast amounts of gold came out of California. Historians have estimated that miners extracted $10 million of gold in 1849, $41 million more of gold the following year, and another $81 million of gold in 1852. The amount declined thereafter, but miners still mined $45 million of gold from California in 1857.

Forty-Niners.

The miners were mostly young males. Forty-Niners (as these...