Thanks to my friend Duane, who passed this gem on to me.
According to The Poker Bride, a new book by Christopher Corbett that traces the journey of many of the first Chinese immigrants in the American West, and reviewed by Melanie Kirkpatrick on Wall Street Journal,
Before the transcontinental railroad, a ship could cross the Pacific Ocean faster than the Pony Express could travel from the West to the East Coast. So in 1848 the news of gold in California reached Hong Kong before it reached Boston. Thousands of Chinese risk takers set sail for what they called the Golden Mountain. In the U.S., they were dubbed “Celestials” or “Sojourners” or “Chinamen,” a designation that did not become a slur until later, Mr. Corbett says.