John Locke was born on February 19, 1792, in Fryeburg, Massachusetts (now Maine). In 1819, Locke graduated from Yale Medical School and briefly served as an assistant surgeon in the United States Navy. He proceeded to embark upon a career as a geologist. Locke participated in government-backed surveys of the Old Northwest and participated in the survey of Ohio completed in the mid-1830s. In 1823, Locke opened a School for Young Ladies in Cincinnati, Ohio. Five years later, he also helped establish the Ohio Mechanics Institute. In 1836, he accepted a position as a professor of chemistry at the Medical College of Ohio. Locke's area of expertise was magnetism, and he invented and improved numerous scientific instruments. Among these instruments were gravity escapements for regulator clocks, the spirit-level, and the electro-chronograph. The electro-chronograph was a magnetic clock. In 1849, the United States government paid Locke ten thousand dollars for several of his instruments. Locke also published textbooks on English grammar for children and on botany. He died on July 10, 1856, in Cincinnati.