Troy weight A grain is 20 mites, a mite is 24 droits, a droit is 20 perits, a perit is 24 blanks. In Scotland, the Incorporation of Goldsmiths of the City of Edinburgh used a system in multiples of sixteen. ("See Assay-Master's Accounts, 1681–1702, on loan from the Incorporation to the National Archives of Scotland".) Thus, there were 16 drops to the troy ounce, 16 ounces to the troy pound, and 16 pounds to the troy stone. The Scots had several other ways of measuring precious metals and gems, but this was the common usage for gold and silver. The Pound was
Heavy metals metals in form or appearance"). This suggestion was ignored; the new elements came to be recognised as metals, and the term metalloid was then used to refer to nonmetallic elements and, later, elements that were hard to describe as either metals or nonmetals. An early use of the term "heavy metal" dates from 1817, when the German chemist Leopold Gmelin divided the elements into nonmetals, light metals, and heavy metals. Light metals had densities of 0.860–5.0 g/cm; heavy metals 5.308–22.000. The term later became associated with elements of high atomic weight or high atomic number. It is sometimes used interchangeably