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
Exchequer Standards inches. According to Secretary Adams, Adams goes on to say (paraphrased and simplified): Thus, the key to the whole measurement system of 1266 was the weight of the silver penny sterling. This penny was 1/240th of the Tower pound, which had been used at the London mint for centuries before the Norman conquest, and which continued as legal tender until 1527, when Henry VIII replaced it with the Troy pound. The Tower pound weighed 3/4 Troy ounce less than the Troy pound (15/16th of the Troy pound). Its penny, therefore weighed 22.5 Troy grains. There was also another pound used