Scale of values, from 0 to 12, for describing wind strength, as defined by Commander (later Rear-Admiral) Francis Beaufort (1774–1857) in 1806; it was adopted throughout the Royal Navy in 1838 and by the International Meteorological Committee in 1874. Originally, the scale determined the wind force from the amount of sail a warship needed to carry to attain a specified speed, with no listing of wind speeds. The modern version, finalized in 1939 by the International Meteorological Committee, included wind speeds. Wind force is now recognized by its common effects on objects in the landscape (dust, flags, trees, etc.) and on people in the open, or on the state of the sea surface. See also saffir–simpson scale; fujita tornado intensity scale; and appendix C.