Discovering Gold in the American River (February/March 1998 | Volume: 49, Issue: 1)

Discovering Gold in the American River

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Authors: John Steele Gordon

Historic Era: Era 4: Expansion and Reform (1801-1861)

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February/March 1998 | Volume 49, Issue 1

On January 24, 1848, one hundred and fifty years ago this month, a man named James Marshall was inspecting a millrace that he had just constructed on the American River, not far from Sacramento, California. He had turned the water into it the night before to clear the debris, and now something “about half the size and the shape of a pea” glinting in the water caught his eye. “It made my heart thump,” he remembered later, “for I was certain it was gold.” To his workmen, he said, “Boys, by God, I believe I have found a gold mine.”

He had, indeed.

It is an oddity of the American past that one of the most significant events in the nation’s history, the California gold strike, should have taken place in a foreign country. But it was not until February 2, 1848, that negotiations to end the Mexican War resulted in the Treaty of Guadalupe Hidalgo. And it was March 10 before the treaty was ratified and the Stars and Stripes rose over the Southwest in exchange for fifteen million dollars. Had Marshall made his discovery only a few weeks earlier, the histories of both countries might have been very different.

Needless to say, the attempt by James Marshall and his employer, John Sutter, to keep the gold find secret was doomed to nearly instant failure. Indeed, Sutler, the owner of fifty thousand acres in the Coloma Valley, was ruined by the onrush of gold miners, and both men would die broke.

The irresistible allure of gold is not hard to grasp. It not only was worth $20.66 an ounce at that time (a very good week’s wage) but could be mined by people without major capital.

Unlike most metals, gold is chemically inert, only very rarely combining with other elements to form molecules. Therefore it is usually found in nature in its pure form, although often as “dust” or small flakes. But another characteristic of gold, its very high density, makes it relatively easy to separate the small particles from other minerals. Density is measured in grams per cubic centimeter. By definition, one cubic centimeter of water weighs one gram. Quartz has a density of about 2.6 grams per cc; iron’s density is a littie less than 8. Gold’s is more than 19. In other words, a gold nugget equal in volume to a mere cubic inch weighs well over half a pound.

This very high density meant that as gold eroded out of the hills and was carried downstream, it settled out of the moving water before anything else. Thus it was concentrated wherever the water slowed down, in an eddy or on the inner side of a bend in the stream. Swirling the gravel found in such places in a broad, shallow pan was enough to find significant gold in rich deposits.

In the early days of the gold rush, it was not uncommon for a man to pan ten or more ounces a