The circular saw was introduced in 1820 by the Shakers, a religious group that formed in 18th century England and immigrated to America in 1774, who allegedly took the idea from the ratchet wheel of a clock. Because it did its cutting continuously instead of by the slow up-and-down method, the process of sawing was speeded up tremendously. However, importing a circular saw into Mexican California in the 1840s was an expensive, months-long endeavor. The sawmill James Marshall designed and built for his employer Captain John Sutter at Coloma was simple and common. A waterwheel, powered by a flow of water through a channel, pushed an old-fashioned sash saw, 7 feet in length, up and down while a cog system pushed logs into the saw. The mill’s estimated capacity was about 1,000 board feet a day. The water channel, or ditch, was also called the tailrace. During an inspection of his mill’s tailrace, James Marshall discovered gold at the bottom of it on January 24, 1848. Today a replica of the sawmill stands at Marshall Gold Discovery State Historic Park in Coloma.