Origins of Scottish measures
In Scotland, as in much of western Europe, weights and measures were based mainly on the Imperial system of measurement, used in the Roman Empire. After the fall of the Empire, standard measures diverged in different parts of Europe, so that, by the early Middle Ages Scottish measures differed from the measures in England and in other parts of Europe. Imperial weights were divided into troy and avoirdupois. Troy weight (the origin of the word troy is obscure but may come from the French town of Troyes) is used by silversmiths to measure gold, silver and gemstones, and was used by apothecaries to measure small amounts of chemicals. Each Troy pound was divided into 12 ounces. Avoirdupois weight (from the French meaning 'to have weight') was used to measure bulkier goods. The avoirdupois pound had 16 ounces, which allowed for easier calculations into quarters. Locally weights and measures were regulated mainly by burghs, where the public weighing machine, the tron (from the old French tronel or troneau, meaning 'balance'), was one of the key places of the burgh. The street where it was situated was often known as the Trongate (gate meaning 'street', from the middle English gate or Old Norse gata), and the Tron was often the site of public meetings and punishments, such as the pillory. In Scotland tron weight meant weight according to a local standard.

Standardization
From the twelfth century onwards the Scottish parliament attempted to standardize local measures, but national standards were not imposed until 1661, when a parliamentary commission in Scotland decided that certain burghs in Scotland would be responsible for keeping standards: Edinburgh kept the 'ell' for linear measure, Linlithgow the 'firlot' for dry measure, Lanark the 'troy stone' for weight, and Stirling the 'pint' (or 'joug') for liquid capacity. The Act of Union introduced English measures into Scotland in 1707, but this meant that English and Scottish measures were now used, and historians must be very careful when dealing with quantities described in documents in the eighteenth and early-nineteenth centuries. Scottish weights and measures gradually disappeared only after the Imperial Weights and Measures Act 1824 (local variations were still in use in some areas in the 1840s).

Metric (SI) system
The efficacy of decimalization in measurement and money had been apparent in European intellectual circles since the late sixteenth century. In 1790 the French National Assembly enforced a system devised by the French Academy of Science, which based measuring units on invariable quantities in nature, and made multiples and divisions of the units decimal. This metric system took its name from the unit for linear measure (the metre) and began to be adopted by many countries throughout the world. In 1960 the system was officially named the Système International d'Unités, or SI for short. The Metric Weights and Measures Act 1864 introduced metric units to the UK, but these were not compulsory. From 1868 onwards attempts were made in parliament to abolish Imperial measure, but it was not until 1969 that a gradual process of phasing out Imperial measures was begun in the UK. Since 1995 most pre-packaged goods have been sold in metric units, and from 1 January 2000 it has been illegal to sell loose products (such as vegetables, fruit, cheese, etc) by pounds, ounces, pints or gallons (with the exception of draught beer, which is still sold in pints).

Bibliography
R D Connor and A D C Simpson, Weights and Measures in Scotland: a European Perspective (Edinburgh, 2004); Mairi Robinson (ed), Concise Scots Dictionary (Aberdeen, 1987); John Ogilvie and Charles Annandale (eds), Imperial Dictionary of the English Language (London, 1882); R E Zupco, 'The weights and measures of Scotland before the Union', Scottish Historical Review, 56 (1977), pp.119-145; I Levitt and C Smout, 'Some weights and measures in Scotland, 1843', Scottish Historical Review, 56 (1977), pp.146-152.

For more information about specific weights and measures and the development of Scottish weights and measures click on one of the following:

Distance and Area
Dry and Liquid Capacity
Weight
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