The distance called mile varies greatly from country to country. Its length is in yards. This intro was supposed to talk about the cultural origin of these traditional units, but I haven`t decided what to write yet. Let`s say they evolved in a more organic and less logical way than SI units. The rest of the discussion follows this sequence: traditional units (length, mass, area, volume), non-metric scientific units (foot-pound-second systems), and then we try to finish it. The corresponding unit of mass is the terribly named snail. The snail is the unit of mass if the pound is a unit of force. A mass of a snail accelerates to one foot per second in the square when pressed by a force of one pound. Start with the avoirdupois pound, the usual unit of mass and weight in the English system.
Si now dominates the world and the mass of English pounds is now defined in relation to the kilogram. The international shipyard and the international pound were taken over by the U.S. National Bureau of Standards with effect from July 1, 1959.   In Australia, the international shipyard and the pound sterling were introduced by Statutory Rule No. 142 of 1961 with effect from 1 January 1964.  The United Kingdom took over the international shipyard and the pound for all purposes through the Weights and Measures Act 1963, which came into force on 1 January 1964.  In October 1958, the International Committee on Measurements and Weights recommended that the measuring instrument be defined in atomic terms (particularly with regard to the orange line of Krypton-86).