The sack (abbreviation: sck.) was an
English unit
English units were the units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxon and Roman systems of units. Various standards have applied to English units at ...
of
weight
In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition.
Some sta ...
or
mass
Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...
used for
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal i ...
and
wool
Wool is the textile fiber obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have some properties similar to animal w ...
.
It has also been used for other commodities by weight, commodities by volume, and for both weight and volume in the United States.
Wool
The wool sack or woolsack ( or ') was standardized as 2
wey of 14
stone
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition, and the way in which it is formed. Rocks ...
each, with each stone
merchants' pound
The pound or pound-mass is a unit of mass used in both the British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legal ...
s each (''i.e.'' 350 merchants' pounds or about 153 kilograms), by the time of the
Assize of Weights and Measures
Weights and Measures Acts are acts of the British Parliament determining the regulation of weights and measures. It also refers to similar royal and parliamentary acts of the Kingdoms of England and Scotland and the medieval Welsh states. ...
. 12 such sacks formed the wool
last
A last is a mechanical form shaped like a human foot. It is used by shoemakers and cordwainers in the manufacture and repair of shoes. Lasts come in many styles and sizes, depending on the exact job they are designed for. Common variations ...
.
[. & & ]
Coal
The coal sack was standardized as an
imperial hundredweight of 112
avoirdupois pounds, approximately 51 kilograms.
Large sack
The large sack was a UK unit of weight for coal. It was introduced by the
London, Westminster and Home Counties Coal Trade Act 1831 (
1 & 2 Will. 4. c. lxxvi), which required coal to be sold by weight rather than volume.
The
Royal Navy
The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
used large sacks holding two hundredweight for
coaling its ships. These sacks were made of
jute
Jute ( ) is a long, rough, shiny bast fibre that can be Spinning (textiles), spun into coarse, strong threads. It is produced from flowering plants in the genus ''Corchorus'', of the mallow family Malvaceae. The primary source of the fiber is ...
bound with
Manila rope
Manila, officially the City of Manila, is the capital and second-most populous city of the Philippines after Quezon City, with a population of 1,846,513 people in 2020. Located on the eastern shore of Manila Bay on the island of Luzon, it is ...
. 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.
Definition
The large sack was defined as 224 pounds.
Conversion
1 large sack ≡ 2 sacks, equivalent to 2 cwt, 224 lb, or about 102 kg
Other uses
The 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 , and in most cases weighs . Other uses in the US include the measurement by volume of salt, where one sack is , cotton where one sack is and flour, where one sack is just . It has also been used as a measure of volume for dry goods in Britain, with one sack being equivalent to .
In British usage, a sack of flour was equivalent to 20 stone, or one-eighth of a long ton. A sack of coal was 16 stone, or , while the weight of a sack of wool depended on who was selling it. A sack of grower's wool was hundredweight or , whereas a sack of dealer's wool was considerably lighter, at .
References
External links
{{Wiktionary, sackful
Tetbury woolsack race
Units of mass
Customary units of measurement