William Stanley Jevons, an English author, born in Liverpool in 1835. He was educated at University college, London, and in 1854 received an appointment in the mint at Sydney, Australia, where he remained five years. He then visited the United States, returned to England, and took the master's degree at the university of London in 1862. In 1866 he became professor of logic and mental and moral philosophy, and lecturer on political economy, in Owens college, Manchester. In 1872 he was elected a member of the royal society of London. He has published a pamphlet demonstrating the depreciation of the precious metals in consequence of the discoveries in California and Australia (1863); "The Coal Question " (1865), pointing out the probable exhaustion of the British coal mines, and the necessity of reducing the national debt; "Elementary Lessons in Logic " (1870); " Theory of Political Economy" (1871), containing an attempt to reduce the science to a mathematical form, and to explain the laws of supply and demand by the aid of the differential calculus; " The Principles of Science " (1874), in which some new views of the value of the reasoning processes are put forth, and syllogistic operations are shown to be practicable by mechanism.