Comparison of the imperial and US customary measurement systems metre, as 1852 metres. Traditionally, both Britain and the US used three different weight systems: troy weight for precious metals, avoirdupois weight for most other purposes and apothecaries' weight for medicines. However, apothecaries' weight has now been superseded by the metric system. One important difference is the widespread use in Britain of the stone of 14 pounds () for body weight. This unit is not used in the United States, although its influence was seen in the practice, until World War II, of selling flour by a barrel of 196 pounds (14 stone). Another difference arose when Britain abolished the
Minor metals Indium (In), Lithium (Li), Magnesium (Mg), Manganese (Mn), Mercury (Hg), Molybdenum (Mo), Neodymium (Nd), Niobium (Nb), Iridium (Ir), Osmium (Os), Praseodymium (Pr), Rhenium (Re), Rhodium (Rh), Ruthenium (Ru), Samarium (Sm), Selenium (Se), Silicon (Si), Tantalum (Ta), Tellurium (Te), Titanium (Ti), Tungsten (W), Vanadium (V), Zirconium (Zr) Minor metals Minor metals is a widely used term in the metal industry that generally refers to metals which are a by-product of smelting a base metal. Minor metals do not have a real exchange, and are not traded on the London Metal Exchange (LME). Two characteristics are regularly associated with minor metals: (1)