The sack (abbreviation: sck.) was an English unit of weight or mass used for coal[1] and wool.[2] It has also been used for other commodities by weight, commodities by volume, and for both weight and volume in the United States.
Wool
editThe wool sack or woolsack (Latin: saccus lanae or lane) was standardized as 2 wey of 14 stone each, with each stone 12+1⁄2 merchants' pounds each (i.e. 350 merchants' pounds or about 153 kilograms), by the time of the Assize of Weights and Measures c. 1300. 12 such sacks formed the wool last.[3]
Coal
editThe coal sack was standardized as an imperial hundredweight of 112 avoirdupois pounds, approximately 51 kilograms.
Large sack
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The large sack was a UK unit of weight for coal. It was introduced by the London, Westminster and Home Counties Coal Trade Act of 1831 (2 Will 4 c lxxvi), which required coal to be sold by weight rather than volume.[4]
The Royal Navy used large sacks holding two hundredweight for coaling its ships. These sacks were made of jute bound with Manila rope. They were filled in the hold of a collier using a scoop and then a wire cable was run through two iron rings at the mouth of the sack to close and hoist it over to the warship, twelve sacks at a time. A sack truck would then be used to take each sack to the chute of the warship's coal bunker where they would be emptied. These sacks were large and heavy, weighing at least sixteen pounds when empty, and costing 11 shillings and sixpence before the First World War.[5]
Definition
editThe large sack was defined as 224 pounds.[1][6]
Conversion
edit1 large sack ≡ 2 sacks, equivalent to 2 cwt, 224 lb, or about 102 kg[1][7]
Other uses
editThe sack has also been used as a unit of volume. In the American oil industry, a sack represents the amount of portland cement that occupies 1.15 cubic feet (8.6 US gal; 33 L), and in most cases weighs 94 pounds (43 kg).[8] Other uses in the US include the measurement by volume of salt, where one sack is 215 pounds (98 kg), cotton where one sack is 140 pounds (63.5 kg) and flour, where one sack is just 100 pounds (45.4 kg).[9] It has also been used as a measure of volume for dry goods in Britain, with one sack being equivalent to 15 imperial gallons (68 L).[10]
In British usage, a sack of flour was equivalent to 20 stone, 280 pounds (127 kg) or one-eighth of a long ton. A sack of coal was 16 stone, or 224 pounds (102 kg), while the weight of a sack of wool depended on who was selling it. A sack of grower's wool was 3+1⁄4 hundredweight or 364 pounds (165 kg), whereas a sack of dealer's wool was considerably lighter, at 240 pounds (109 kg).[11]
References
edit- ^ a b c Cardarelli, F. (2003). Encyclopaedia of Scientific Units, Weights and Measures. Their SI Equivalences and Origins. London: Springer. pp. 48. ISBN 978-1-4471-1122-1.
- ^ Cardarelli, F. (2003). Encyclopaedia of Scientific Units, Weights and Measures. Their SI Equivalences and Origins. London: Springer. pp. 49. ISBN 978-1-4471-1122-1.
- ^ Ruffhead, Owen, ed. (1763a), The Statutes at Large, vol. I: From Magna Charta to the End of the Reign of King Henry the Sixth. To which is prefixed, A Table of the Titles of all the Publick and Private Statutes during that Time, London: Mark Basket for the Crown, pp. 148–149. (in English) & (in Latin) & (in Norman)
- ^ John Holland (1835), "The London Coal Trade", The History and Description of Fossil Fuel, the Collieries, and Coal Trade of Great Britain, London: Whittaker, pp. 374–386
- ^ Lt. Lewis Freeman (1919), "Coaling the Grand Fleet", Stories of the Ships, London: John Murray, pp. 216–231
- ^ Holland. The History and Description of Fossil Fuel, the Collieries, and Coal Trade of Great Britain. Second Edition. Whittaker. 1841. Page 386.
- ^ Gilbert Jenkins. "Coal Weights, UK". Oil Economists' Handbook. Elsevier Applied Science Publishers. 1986. Page 325. Google Books.
- ^ "Oilfield Glossary - Sack". Schlumberger. Retrieved 9 June 2018.
- ^ "A Dictionary of Units of Measurement". University of North Carolina. Retrieved 9 June 2018.
- ^ "Manuscripts and Special Collections - Glossary". University of Nottingham. Retrieved 9 June 2018.
- ^ "Forgotten British and Irish units". Metric Views. 14 June 2013. Retrieved 9 June 2018.
External links
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